The Flora of the Parkland Walk

 

Introduction

The Parkland Walk

The Parkland Walk follows the course of a former railway line that used to run from Finsbury Park, via Highgate, to Alexandra Palace through the London boroughs of Haringey and Islington. The last passenger train ran in 1954, and the railway closed soon after, with the rails being taken up in 1971. The land was purchased by the two boroughs, initially with a view to building houses. However, local residents were opposed to this and a Public Inquiry was held in 1978. The Inspector found in favour of the residents and work on developing a linear green Walk commenced in 1980. The Parkland Walk was officially opened in 1983 and declared a statutory Local Nature Reserve (LNR) in 1990. At nearly two and a half miles in length, it is London’s longest LNR. An account of the history of the railway line and the creation of the Parkland Walk was published in 2006 (Davies and Bevan, 2006). 

The Survey

The author was asked to carry out a botanical survey of the Parkland Walk early in 2015 and to advise on suitable management to benefit the flora. The survey, covering flowering plants, ferns and horsetails, was carried out between March and October 2015. The Walk was divided into 26 compartments as mapped (with a few minor modifications) in the Parkland Walk Conservation Management Plan (Riley, 2010). These seven maps, showing the compartment boundaries, are attached.

map 1
map 2
map 3
map 4
map 5
map 6
map 7

To achieve an even coverage of recording, each compartment was visited three times during the course of the year, and an appropriate amount of recording time and effort was devoted to each. A total of 41 hours fieldwork was spent on the survey. I was very grateful for the assistance provided by David Solomon and Maria Precedo, from the Friends Of the Parkland Walk, but all identifications were confirmed by myself. Voucher material was collected from plants where identification could not be confirmed in situ. In a few cases (e.g. hybrid Roses), material was sent to an expert referee for determination. The resulting plant list was compared with an earlier one compiled between 1981 and 1983 (Bevan. 1984).

Results

A total of 291 taxa (species, subspecies and named varieties) was recorded. Table 1 lists these taxa by both English and Latin names. The status of each taxon is shown. Native plants (N) are those that are native in Middlesex; introduced natives (I) are those that are native elsewhere in England, but introduced in Middlesex; archaeophytes (Arc) are ancient alien plants known to have been introduced before 1500 AD; and neophytes (Neo) are more recent aliens, introduced after 1500 AD. The terms “non-native” and “exotic” are also sometimes used in the text to indicate alien plants in general. Trees known to have been planted are marked with a P, but there are many cases where such trees have given rise to naturalised offspring. Trees (T), shrubs (S), grasses (G) and ferns (F) are all indicated. Table 1 also shows the comparative frequency of each taxon, enabling us to establish that Common Ivy is the most frequent plant on the Walk, found in 25 of the 26 sub-compartment.  Finally, Table 1 lists the taxa found in each sub-compartment. Although each of the sub-compartments supported an average of 53 taxa, these were not evenly distributed. As might be expected, the larger sub-compartments generally supported the greatest number of taxa. For example, the most diverse sub-compartment, and one of the largest (8c), supported 93 taxa; whereas the least diverse was also the smallest (3d), supporting only 16. The five Muswell Hill sub-compartments had a slightly higher average diversity (62 taxa). The richest of these was 12b (St James’s Lane Viaduct) which, although one of the smallest, supported 73 taxa. In this case, the wide range of habitats found within the sub-compartment  open grassland, scrub, brickwork, path sides and a fringe of woodland, all contributed to the diversity of plants present.

Discussion

Native species

Native plants exceeded aliens by a small majority (54%). They are shown in Table 1 with an N (native to Middlesex) or an I (native elsewhere in the UK, but introduced in Middlesex). There were 36 species of native trees and shrubs, ranging from the almost ubiquitous Ash (22 compts.), Hawthorn (21), and Bramble (18), to the much scarcer Hornbeam (4), Beech (2), Alder (2) and Spindle (1). Native species are particularly highly valued by ecologists for the wide range of associated wildlife that they support. They are especially important for dependent invertebrates. The White-letter Hairstreak butterfly, for example, is scarce on the Walk, and entirely dependent on Elm or Wych Elm – the larval food plants. The native Box is a rare and declining tree on the chalk of SE England (classically at Box Hill in Surrey), but it is also widely established in gardens as a valuable hedging plant. It occurs at a single location in compartment 6, which may once have been part of a garden extension, and has been known from there for over fifteen years. The Large-leaved Lime is another native tree, which is found in a few parts of SW and S. England, but it is also sometimes planted in parks and gardens. It was found in just two compartments. This is sometimes joined by the Common Lime (a hybrid), which has been abundantly planted as a street tree in London and was found in 8 compartments on the Walk. The Yew tree is not native to Middlesex, but has spread widely from planted specimens in parks, gardens and churchyards. It was found in 8 compartments. Both native Oaks were recorded, together with two examples of the hybrid between them. Oaks are particularly rich in invertebrate life, with more than 400 associated insects in the UK (Kennedy and Southwood, 1984). It should be remembered that there were few if any trees or shrubs along the original railway line, and nearly all have arrived, or been planted since its closure in 1954. A few herbaceous native plants are also grown in gardens and sometimes escape. These include a number of ornamentals such as the Stinking Iris, a local plant of calcareous soils, which is often grown as its yellow-flowered cultivar (var. citrina). This was the only form found on the Walk. A small colony of Coralroot was discovered close to the old Crouch End station platform (7a). This is a scarce native plant, found in a few places in the Chilterns and in the Weald, but the Parkland Walk colony is likely to have originated in a garden, where it is occasionally grown as an attractive ornamental. Our plants match a European variety (forma ptarmicifolia) and this may be the first Middlesex record (Mark Spencer, pers. comm.).  Sadly, many native plants appear to have been lost from the Walk since the 1980s. Table 2 lists the 54 species that were recorded between 1981 and 1986 but not refound during the current survey. The various reasons for their decline are discussed below (see “The Changing Flora”) and proposals for selected re-introductions are given under “Management Recommendations”.

 Alien species

46 % of the plants recorded were non-native. They have been split into two groups according to the date of their supposed introduction to the UK. Much the largest of these (86%) are comparatively recent arrivals (after 1500 AD) known as neophytes (Stace and Crawley, 2015). Their high number is largely explained by the urban nature of the Walk, with houses and gardens forming most of the boundaries. Many such species have “escaped” from gardens and some now exert a considerable ecological influence on the Walk. The Sycamore, for example, has long dominated parts of the Walk and was found in 22 sub-compartments. Being able to germinate in quite dense shade, this vigorous tree has successfully out-competed most other trees. Few insect species are associated with Sycamore (though the few that are can be present in large numbers). Recommendations about its control are given below (see “Management Recommendations”). The Holm Oak was recorded from 17 compartments. This is a comparatively recent arrival on the Walk, which was first found as a single sapling in 1983 (Bevan, 1984). It has been spreading fast, partly as a result of climate change. Native to the Mediterranean and SW Europe, this is now particularly well adapted to the sunny, south-facing embankments of the Walk. It may need to be controlled in some places. The Turkey Oak, another warmth-loving S. European tree, widely naturalised in England, has been less successful and was found in only two sub-compartments. The familiar Bay tree, also from the Mediterranean, is spreading fast. It is now well established in five compartments, but was not present in the 1981-1983 survey. One of the most successful exotic shrubs is the Butterfly-bush, familiar in very many parts of London. Found in 12 sub-compartments, it is particularly at home growing on the brickwork of the bridges, a similar habitat to the cliffs on which it is found as a native in parts of China. Japanese Privet has advanced onto the Walk in many places from boundary hedges, but it is only rarely self-sown. Fig trees grow at both ends of the southern section of the Walk (compt. 2 and sub-compartment 10c). They have been known from both sites for more than thirty years. Although one of them regularly produces figs, they will not spread, as their seeds fail to ripen in the UK. A solitary Stag’s-horn Sumach grows in compartment 2 (known there since before 1980), and may have been originally planted, though it can spread extensively by suckering. Many ornamental Cotoneasters are grown in gardens and birds frequently consume their berries. Stace (2010) lists 83 different kinds that have been found in the wild. We have found just six different species, but have only managed to name two. Other exotic shrubs include Cherry Laurel and Cherry Plum, together with frequent garden forms of Mock Orange, Highclere Holly and Evergreen Spindle. However, the most significant alien shrub, in terms of its ecological impact, is arguably the “Himalayan Giant” Bramble, which was found in 19 compartments. This wickedly spiny, but large-fruited, vigorous introduction has invaded many parts of the Walk – to the delight of blackberry pickers, but to the disadvantage of many native plants which cannot compete with it. 

Many non-native herbaceous plants were also recorded. They include the colourful Oxford Ragwort with its bright yellow flowers, which is often found on railway land. This was once more widespread (and its hybrid with Sticky Groundsel used to occur), but it is now reduced to just two compartments (see “The Changing Flora”). Canadian Goldenrod is also much less widespread than formerly, and now reduced to only a single compartment. By contrast, Guernsey Fleabane, first recorded in 1985, is now widespread.

 The only Bluebells recorded were escaped Spanish hybrids, which are much better adapted to the dry, well-drained soils than the natives, which prefer the humus-rich soils of old woods.

Spanish Bluebell hybrid

The notorious Japanese Knotweed has resisted prolonged efforts at eradication in 8 compartments, and it has been joined by extensive growths of its vigorous climbing relative, the Russian Vine in five others. The latter is a familiar sight in parts of the northern (Muswell Hill) section, where it scrambles high into the tree canopy in several places.

 Planted trees and shrubs

 The first Parkland Walk warden, David Hope, and his small conservation team, planted many of the existing trees on the Walk in the early 1980s (Table 1). These included Pedunculate Oak, Silver Birch, Field Maple, Large-leaved Lime, Common Lime, Wych Elm, Rusty Sallow, Goat Willow, Hornbeam and Beech. They also planted a large number of native shrubs, including several different Roses (Dog Rose, Burnet Rose, Many-flowered Rose and various hybrids), and much Hawthorn.

Hawthorn

Many of these have now spread far from their original planting sites. A few non-native trees have also been deliberately planted. They include a fine Pillar Apple, about 50 feet tall, which grows very close to the entrance from Muswell Hill (12c). It bears brightly coloured crab apples in the late summer and its leaves turn a striking gold and scarlet in the autumn. Also in the Muswell Hill section (12a), a tall, variegated form of the Balm-of-Gilead Poplar, escaped detection until the end of the survey, although its far-creeping suckering leaves could easily be seen before the tree itself was found. Jacquemont’s Birch, with its remarkable white bark, has been planted in the southern section of the Walk (9b). An enormous Pear tree was found near Crouch End Hill Bridge, hidden among other trees at the top of the south embankment of 8a. There are a few large planted Hybrid Black-poplars, which must be some of the oldest trees on the Walk. A group with around a dozen large trunks grows near the boundary between Haringey and Islington (compartment 6) and appears to be the male clone ‘Serotina’. A similar mature, though much pruned, tree was planted in compartment 12c close to the entrance path from Muswell Hill.

 The Changing Flora

 The flora of the Parkland Walk has seen many changes since the days when it was a working railway more than sixty years ago. There are no records of the plants growing on the embankments and cuttings of the earlier railway, but we do know from contemporary photographs that these would have been dominated by grassland. It is unlikely that trees of any size would have been permitted to grow close to the track, and the grassland would have been regularly cut or burnt. Therefore, none of the trees that now dominate many parts of the Walk will be more around 60 years old and most are a lot younger. Following the closure of the passenger railway in 1954, the regular maintenance of the rail-side land ceased and shrubs and trees began to colonise. When I first visited the Walk in the early 1980s, it was a lot more open and less wooded than it is today. I compiled a list of the plants I saw between 1981 and 1983 (Bevan, 1984). There were 238 taxa, with a further 34 that I added between 1984 and 1986. This gives a total of 272 species seen between 1981 and 1986, which is very close to the number seen during the current survey. Although care should be taken in comparing the two surveys (as the first covered a much longer time period), they do nevertheless show some interesting contrasts. In the first survey, (62%) of the plants seen were natives. This has fallen to 54% in the current survey and 54 native species were not refound (Table 2). It is, of course, possible that some of these could have been overlooked or may survive as buried seeds, and I would be delighted to hear of the re-discovery of any of these “lost natives”. They are largely grassland species or plants of other open habitats. Their decline is due to a range of factors. Firstly, and most obviously, succession has taken its toll. The earlier grasslands and other open habitats have slowly succeeded to scrub and woodland. The consequent loss of light, has led to the decline of many light-demanding species. Secondly, the spread of certain alien plants has led to competitive exclusion. A good example here is the steady decline of the native Hedge Bindweed, which was widespread in the 1980s, but is now rare and confined to just two sub-compartments. The more vigorous non-native Large Bindweed has now taken its place. Thirdly, there has been a large increase in the number of dogs using the Walk. This has enriched the soils by adding phosphates and nitrates (already increased through atmospheric pollution) and has favoured more competitive species. For example, four species of clover, once frequent along the old track-way, have been unable to compete with coarse grasses like Cock’s-foot, Perennial Rye-grass and False Oat-grass. These, together with Greater Plantain and a few vigorous alien species such as Green Alkanet and Michaelmas-daisy, have all thrived in the richer soils. They have overwhelmed the less competitive natives, which do better on poorer soils.

In a few cases, climate change may also have played a part, even over such a limited time period. The rapid spread of the Mediterranean Bay tree and the Evergreen Oak has already been mentioned in this context.

A few wetland plants have declined following recent drainage work on parts of the track-bed. There was once a thriving colony of Water Mint in wet ground in compartment 8a, and a few fronds of Lady Fern grew close by. These have not been seen recently as the ground has dried out.

In contrast to these losses, woodland natives are doing better. Well adapted to shady habitats, they are less affected by some of the issues mentioned above. Tutsan is a particularly welcome arrival (11a). This attractive St John’s-wort, sometimes grown in gardens, has always been rare in Middlesex (Kent, 1975), but in recent years has been spreading in local woods (Bevan, 2011).

Tutsan

Stinking Iris was found in six compartments, and is also widely grown in gardens, often as the yellow-flowered cultivar (var. citrina). This was the only variety found on the Walk. A small population of Primroses was found in 8a, probably deliberately introduced, but now well established. The most unexpected woodland native found was Coralroot, which was described earlier (see “Native Plants”). Violets also sometimes escape from gardens and we recorded two species in woodland compartments: Early Dog-violet and Sweet Violet. These were both very scarce on the Walk and their numbers too low to support the larvae of the increasing numbers of Silver-washed Fritillary butterflies now recorded (see “Management Recommendations” for 10d). No Violets were recorded in the 1980s. Only a few ferns grow on the increasingly dry embankments and cuttings, but one new native, the Soft Shield-fern, is spreading in North London (Bevan, 2011; Kent, 2000) and, though absent in the 1980s, is now established in three compartments.

As this survey has indicated, many native plants are in decline on the Walk, and are giving way to better-adapted exotic species, mainly from warmer countries. These changes mimic similar processes happening elsewhere in London’s green spaces, so that the Parkland Walk could well be considered something of a microcosm for the city as a whole.

Management Recommendations

General objectives

As we have seen, much of the Parkland Walk is now wooded, and without suitable management intervention the existing grassland areas will soon become so. Such a process of succession will result in the continuing decline and eventual loss of many light-demanding species. It is therefore essential to identify the best existing grasslands and to make sure that they do not succeed to woodland.

Grassland management

As mentioned earlier, the increasing dog population has had a significant and largely negative impact on the flora. In particular, soils close to the central path have become heavily enriched with nitrogen and phosphorus. This has benefited a limited number of vigorous grasses, nettles, docks, brambles and several alien species (Stace and Crawley, 2015), but has led to the decline of many natives. There is little that can be done to change this situation close to the central path, but it should be possible to identify sites further afield where dog activity is less severe. In such protected areas, the establishment of suitable native species could be attempted, though the successful re-introduction of many of the “lost natives” will be challenging.

In many of the wooded compartments, Sycamore has become the dominant tree. Whenever opportunities arise, and particularly where the tree is shading out native species, it should be removed. The proposals set out below for each sub-compartment (as shown on the attached maps) should be read in conjunction with those outlined in the Parkland Walk Conservation Management Plan (Riley, 2010). The plants found in each sub-compartment are shown in Table 1 (“by compartment”).. My own recommendations focus on botanical issues and rarely conflict with the earlier proposals but where they do so, my alternative is fully explained.

Management Recommendations by Compartment

 Compartment 1

 A valuable open area where several planted Field Maples were recently felled and the adjacent scrubland cleared. It is important that any re-growth of these trees should be controlled. The area should be strimmed annually (preferably in late September). Two rarities were found here: the ornamental Bleeding-heart, and an unusual form of Large Bindweed with a deeply lobed corolla (var. quinquepartita). A group of native Burnet Roses were planted about 20 years ago near the southern entrance and is spreading. A fine Hazel, the largest on the Walk, is of particular note, and should be protected. This is a valuable, sheltered site for butterflies, though the wide grassy central path has suffered from intensive dog activity and supports few species.

Compartment 2

 This is a large wooded area, which includes the bridge over Upper Tollington Park. The densely wooded embankments are surprisingly diverse and support some plants not found elsewhere on the Walk. Several unusual aliens were found, including a sapling Loquat found by David Solomon. This small evergreen tree is now often grown in gardens in Haringey and seedlings are appearing quite widely in the borough. Some of these may result from people discarding purchased fruits, but the tree does flower and fruit in a mild winter. It appears to be spreading in Haringey although it is not mentioned in either Stace (2010), or Stace and Crawley (2015). A mature Stag’s-horn Sumach, and a large Fig tree, grow close to the footpath. These two have been known from here for more than 35 years. A single Tree Mallow was found close to the central path. This is a scarce native biennial of western and central coasts of Britain and a most unexpected and welcome discovery on the Walk. I first

Tree Mallow

recorded it in 2004, when it was found opposite the entrance from Blythwood Road (compt. 6). Apparently it once grew in a garden there, from whence it must have escaped. It is remarkable that it still survives on the Walk eleven years later.

Early Dog-violet

The only Early Dog-violet to be found on the Walk was seen here on March 9th.. I agree with the 2010 management recommendations, but care should be taken to protect the above plants when cutting back the path-side vegetation as recommended.

 Compartment 3

This important grassland area was divided into four sub-compartments in the 2010 Plan. However, succession has blurred the boundaries between two of these, so we have included sub-compartment 3c with 3b. There are now therefore three sub-compartments (3a, 3b and 3d). They lie on the steep embankment slopes between Florence Road and Lancaster Road. This is the largest area of grassland on the Walk and, although it has lost much of its earlier native flora (see “The Changing Flora”), it remains of high value and great potential.

Sub-compartment 3a contains the best grassland, with plentiful Zigzag Clover, Meadow Vetchling, Goat’s-beard, Smooth Tare, Autumn Hawkbit, Black Medick and a range of grasses. However, it has lost much of its earlier native flora such as Bird’s-hoot Trefoil, four species of clover, Perforate St John’s-wort, Burnet-saxifrage and Mouse-ear-hawkweed (see Table 2). Unfortunately, these cannot easily be re-introduced owing to the nutrient-rich soil. Without great care they are likely to be overwhelmed by more vigorous species. The loss of Bird’s-foot Trefoil is particularly regretted, as it is the chief larval food plant of the Common Blue butterfly, once frequent on these slopes.

Bird’s-foot Trefoil

However, those existing species, which are better adapted to the rich soils, including Rosebay Willowherb, Michaelmas-daisy and Zigzag Clover, could all be encouraged to spread.  Towards the bottom of the embankments, in places where succession is less advanced and dog activity minimal, attempts could also be made to re-introduce some of the “lost natives” mentioned above, though this is likely to be a more challenging task. Plugs could be planted out in the autumn, given some protection and regularly watered. Their progress should then be regularly monitored.

Sub-compartment 3b fringes the grassland and contains advancing tall herbs, shrubs and tree saplings from the wooded lower slopes of the embankment. It is important that this advance is halted, for there is a real danger that the grassland could shrink as it succeeds to woodland. Care should be taken here, as the compartment contains some unusual plants that are rare or absent elsewhere on the Walk. There is a single plant of Meadow Crane’s-bill on the northern embankment, and a small population of the rare and beautiful, pale pink, Hairy Bindweed has been known for thirty years on the southern side. Its even scarcer hybrid with the ubiquitous Large Bindweed has also been found here.

Sub-compartment 3d is a small area of marshy vegetation supporting a population of Yellow Iris, a native Alder and much Ground Elder. Wetlands are very scarce on the Walk and this one should be protected. The invasive Ground Elder should be removed and the possibility of establishing native wetland plants should be investigated.

Compartment 4

This is another largely wooded area, divided into three sub-compartments. The largest of these, sub-compartment 4a, consists of the embankment slopes on either side of the central pathway. There are two mature native Oaks at the eastern end, close to the path. One is a Pedunculate Oak, and the other is a hybrid. Both were probably planted in the early 1980s. Close by is a self-sown Evergreen oak, which, as discussed above, has been spreading rapidly along the Walk and needs to be watched. There is a patch of Japanese Knotweed towards the western end (close to Lancaster Road) that needs to be controlled. Traveller’s-joy is abundant here, clambering up into the adjacent trees. This is a native plant of free-draining chalky soils. It is established in 7 compartments on the Walk, where it is well adapted to the underlying soils that contain much calcareous brick rubble.

The western end of sub-compartment 4b, close to Stapleton Hall Road, is dominated by Traveller’s-joy. This is a south-facing steep slope and is relatively free of dogs. It is another potential site for introducing some suitable grassland species, including some of the “lost natives” mentioned under 3a. The Traveller’s-joy would need to be controlled, but otherwise, the site seems well suited. David Hope carried out a similar project back in the 1980s, when he introduced a number of wild flowers into the adjacent sub-compartment 4c. Most of these succumbed to competition, but Bush Vetch did well and is still present today – demonstrating that suitable introductions can succeed. Both Periwinkle species have become well naturalised here, and a planted ornamental Viburnum (V, x bodnantense) is well established near the ramped entrance path.

Compartment 5

Another heavily wooded area dominated by Sycamore and Ivy, but supporting a diverse range of other trees, including the Walk’s only Common Whitebeam (probably originally planted), together with Pedunculate Oak, Silver Birch, Turkey Oak, Evergreen Oak, and Highclere Holly. Shrubs include the Walk’s only Pink Snowberry, occasional Spotted-laurel, Cherry Laurel and Evergreen Spindle. One of only two known colonies of Sweet Violet was growing close to the central track, and native Ramsons and Stinking Iris were found close by.

I agree with the earlier management proposals, but special care should be taken when managing the path-side vegetation to protect the above plants.

 Compartment 6

This is a small compartment lying adjacent to the eastern boundary of Islington. It seems likely that part of its northern section was once a garden extension, for no less than five alien species have their only occurrence here. These are all garden plants that have become naturalised: Chinese Barberry, Dusky Crane’s-bill, Lungwort, Greater Celandine and Walnut. There is also a fine population of mature False Acacia trees which, though originally planted, are now spreading by suckers. A large multi-stemmed group of Hybrid Black-poplar grows on the southern side of the path close to the Islington boundary. Another Tree Mallow, discussed in C.2, was found close to the path, near to where it was first recorded in 2004.

The sheltered, open nature of this compartment was mentioned in the 2010 Plan and its value for invertebrates noted. I agree, and believe that more could be made of its potential for butterflies and other insects by suitable planting.

Compartment 7

This lies in a cutting on either side of the old Crouch End Station platforms. It was divided into four sub-compartments in the 2010 Plan, but the boundaries of one of these (7c) can no longer be made out, so it has been included in an enlarged sub-compartment 7b.

Sub-compartment 7a lies to the north of the old station platform and is heavily wooded away from the platform itself. A wide range of trees and shrubs was found, including several unusual exotics that were planted by the owner of an adjacent garden in the 1990s. False Holly, Chinese Privet and Oregon Grape are three such examples. Other alien trees and shrubs have established on their own, and include, Highclere Holly, Evergreen Spindle, Lilac and Lawson’s Cypress. There are a few native herbs, not found elsewhere on the Walk. They include Great Burdock and Dog’s Mercury. Hop, found in just two other sites, grows close to the steps at the western end.  A small population of the rare Coralroot grows close to the edge of the platform. This has been discussed above (See  The Changing Flora”).

The 2010 Plan suggests removing young Ash and Sycamore from this compartment and coppicing other suitable trees (Hawthorn, Ash, Hazel and Elm, etc.) on a five-year rotation. The Plan also recommends felling Sycamores on the north-facing slope (7b). This would certainly help to bring additional light to 7a, and benefit the ground flora. My main concern here would be to protect the rare Coralroot and some of the other shrubs mentioned above. 7a is traversed by a narrow path running along the top of the slope, parallel with the platforms and leading at the western end to the steps up to Crouch End Hill Bridge. Consideration could be given to creating a couple of glades close to this path, where some of the lost woodland flora (e.g. Foxglove, Bugle, Nettle-leaved Bellflower, Greater Stitchwort, etc.) might be re-established. Such woodland species are more likely to succeed than many of the lost grassland plants discussed earlier, as the soils here are less nutrient rich and the plants could be better protected. This path could also be used as part of a new nature trail.

Sub-compartment 7b (including the merged 7c) forms the wooded southern side of the cutting and its trees and shrubs have grown up through a thick layer of rubble.. A large Bedford Willow grows at the western end, close to Crouch End Hill Bridge. There is also one of the few Sessile Oaks on the Walk, growing close to the southern boundary fence, together with several Large-leaved Lime trees. Chinese Bramble covers a small area of the woodland floor and has been known here for more than twenty years. Sub-compartment 7d occupies the space between the two platforms. It supports a range of shrubs, including Goat Willow and Rusty Willow, and various tall herbs including much Russian Comfrey and Rosebay Willowherb. I agree with the earlier management proposals for this sub-compartment.

Compartment 8

This compartment contains the longest continuously wooded area on the Walk. The usual trio of canopy trees – Sycamore, Ash and Pedunculate Oak, dominates the woodland, but it also supports Silver Birch, Common Lime, Highclere Holly, Wych Elm and Bay. A huge Pear tree, around 50 feet tall, grows at the top of the southern embankment of sub-compartment 8a. The northern embankment of 8a is home to the only population of Primroses on the Walk. These are likely to have been originally planted several years ago, but are now well established. Colonies of Sweet Violet and Red Campion grow close by. These three natives are declining and could be encouraged to spread by further planting and by removing brambles and other competitors.

There are three notable additions in sub-compartment 8b. Two large bushes of the ornamental Many-flowered Rose were planted neat the western end and are a fine sight in mid-summer. Native Honeysuckle has invaded from an adjacent garden and is found nowhere else on the Walk. Soft Shield-fern was found near the southern boundary. This fern, formerly very rare in London, is discussed under “The Changing Flora”.

Sub-compartment 8c now includes the much smaller sub-compartment 9a, lying immediately east of Northwood Road Bridge. The boundaries separating these two have become blurred through rapid succession over the last five years. The enlarged 8c is now one of the largest sub-compartments on the Walk and has the distinction of being the most diverse, with 93 taxa. This high diversity includes a range of light-demanding plants that have colonised the southern embankment following the recent felling of several Common Limes on the east of the steps down to Milton Park. These include, Spear-leaved Orache, Many-seeded Goosefoot, Feverfew, Yellow Corydalis, Russian Comfrey, White Comfrey, and Groundsel. These are mostly very common plants, but they are currently scarce on the Walk through lack of light. Further selective tree felling would allow them to spread.  Clif Osborne recorded Sulphur Cinquefoil just to the east of Northwood Road Bridge. This attractive garden plant was established on Tottenham Marsh for some years and it will be interesting to see if it persists on the Walk. A Beech survives on the northern wooded embankment (in one of only two sites), and the Walk’s only wild Butterfly Stonecrop has escaped from a garden close to the fence line. A population of slowworms used to inhabit the land immediately to the southeast of Northwood Road Bridge. These were last recorded (by Will Atkins) in 2003, and may still be present. A reptile survey should be carried out before any management decisions are made for this area.

Compartment 9

Sub-compartment 9a in the 2010 Plan has been included in sub-compartment 8c, as there is no longer any obvious dividing line between the two. As a result Compartment 9 is now represented only by sub-compartment 9b. A substantial area of garden extensions lies to the north, separated from the Walk by a line of Lawson’s Cypress. Butterfly Bush and Cherry Laurel are frequent along this narrow stretch and need to be cut back where they overhang the path. A fine Jacquemont’s Birch has been planted on the southern side of the path. Vegetation obscuring the striking white trunk of this tree should be cut back when necessary.

Compartment 10

This compartment, which forms the westernmost end of the Walk has been divided into four sub-compartments and each contain some interesting botanical features. Sub-compartment 10a, forming a narrow strip of sycamore-dominated woodland, runs down from the Walk’s entrance on Holmesdale Road. The property known as 3, Francis Place lies along part of its northern boundary. This wooded strip supports a colony of Giant Fescue, scarce elsewhere on the Walk, and a number of damp-loving plants, including Pale Willowherb and Hoary Willowherb, have colonised a poorly drained edge of the path. Sub-compartment 10b, an area of dense Sycamore and Ash woodland, once housed a small playground. The woodland floor is dominated by native ivy, but there is also some escaped Algerian Ivy, which is very scarce elsewhere. A large Sowbread growing close to the path was in full flower at the time of the survey visit in September. A single Soft Shield Fern was also found. In a small marshy area, immediately adjacent to 3, Francis Place, Yellow Iris has recently established and other wetland plants (Water Mint, Brooklime, Mash Marigold, etc,) might also be introduced. There is very little wetland on the Walk, so this area is of potential interest. However, it was unclear at the time of the survey as to the permanence of this wet area – it might simply be a leaking pipe from 3, Francis Place. The hydrology of the area would need to be established before any planting is undertaken. 

Sub-compartments 10c and 10d comprise an area known locally as the Highgate Bowl. This is where the former railway line entered the tunnel leading to Highgate Station. Sub-compartment 10c forms the wooded surround to the Bowl. This woodland is very diverse where, in addition to the usual Sycamore, Ash and Pedunculate Oak, there are also Silver Birch, Common Lime, Hornbeam, Hazel, Goat Willow, Yew, Apple, Alder, Mountain Ash and Beech. There is even a Fig tree, which once produced plentiful figs each year. It has now become over-shaded by other trees and needs to be rescued. With a total of more than twenty tree species, the Bowl would make an ideal site for a “Tree Trail”, which could include the above listed species and several others.

Sub-compartment 10d was once grassland, and although it has now largely scrubbed over, it still retains a range of sun-loving plants including Meadow Buttercup and Red Clover, which are now surprisingly scarce on the Walk. There are also good populations of Creeping Thistle and Spear Thistle and plentiful Bramble. These are particularly favoured by butterflies and other nectar-loving insects. The recent sightings of the scarce Silver-washed Fritillary have all been made here. Indeed, the sheltered nature of the Highgate Bowl and its rich array of nectar sources, make this the best butterfly site on the Walk. Management should therefore be focussed on retaining its open nature and encouraging the nectar-rich flora by judiciously cutting back overhanging trees and shrubs, and strimming the remnant grassland each autumn.

 Compartment 11 (Parkland Walk North)

Compartment 11 is divided into two sub-compartments, 11a and 11b. Sub-compartment 11a is a narrow strip of woodland running eastwards from Muswell Hill Road. It supports a remarkably diverse flora, which is particularly rich close to the entrances from Cranley Gardens and from Muswell Hill Road. At the Cranley Gardens entrance there has been some planting of various ornamental Ivies, which includes a vigorous plant of the variegated cultivar of Algerian Ivy “Gloire de Marengo” and some Persian Ivy, which is also naturalised elsewhere on the Walk. There is a colony of the native Wall Lettuce, which has not been found anywhere else and is a scarce plant in Haringey. Although not strictly within the survey area, the sloping access path leading down from Muswell Hill Road to the Parkland Walk entrance tunnel, has some interesting botanical features. There is an overgrown flowerbed in which a self-sown Tree-of-heaven has become established. The surrounding brickwork supports Pellitory-of-the-wall and a few plants of an attractive exotic grass, Greater Quaking-grass. Back on the Walk itself, there is an area of scrubby vegetation opposite the entrance from Cranley Gardens. Here can be found a large Tutsan plant, rarely seen away from ancient woodland, and thought to have escaped from a local garden. Close-by, and probably from the same source are Himalayan Honeysuckle and Purple Toadflax. Growing out from the narrow embankment on the north side of the path is a large colony of Great Horsetail. This impressive native fern-ally follows the spring line, which runs parallel with the edge of the Walk. On the southern side a woodland strip supports much Traveller’s Joy and Russian Vine, and a single bush of the hybrid between Hawthorn and Midland Hawthorn (the latter parent probably coming from nearby Highgate Wood).

Sub-compartment 11b comprises a south-facing slope, which is dominated by Bramble, much of which is the non-native micro-species “Himalayan Giant” which, having originally escaped from cultivation, produces very large blackberries. A few spikes of Common Valerian were found close to an informal access path to an adjacent garden. This damp-loving native is now a rare plant in London and has not been found elsewhere in Haringey. Like the neighbouring Giant Horsetail, it depends on the underlying spring line for its existence. There is also a small surviving population of native Hedge Bindweed, which has now rarely seen in Haringey, having lost out to its more vigorous alien relative, Large Bindweed. The latter is now abundant in many parts of the Walk, and is here joined by the hybrid between the two. In the earlier Management Plan, there was a recommendation to “brush cut and remove” Bramble from 75% of the sub-compartment over a three year period (25% /year), and to remove the remaining 25% on an annual basis. It was suggested that this would be of benefit to reptiles. I have reservations about these recommendations. Firstly, I am not aware of any recent reptile records for the site, and I don’t think this would be a suitable venue for their possible introduction. Secondly, I am concerned about the effect such management would have on the plants mentioned above. Finally, I think at least some of the “Himalayan Giant” Bramble should be retained, as they are very popular with blackberry pickers on the Walk. However, there are clearly some advantages in the proposals for light demanding plants, as can readily be seen where some initial clearance has already taken place. This has allowed plants like Wood Forget-me-not, Meadow Vetchling, Canadian Fleabane, Spear Thistle and others to thrive. I think a scaled down version of the 2010 Plan, allowing around a third of the bramble to survive, would be more suitable.

Compartment 12 (Parkland Walk North)

The compartment is divided into three sub-compartments of contrasting character. Sub-compartment 12a occupies a broad cutting and is dominated by mixed woodland in which mature Pedunculate Oak, Sycamore, Wild Cherry, Hornbeam and Birch all occur. A large variegated Balm-of-Gilead Poplar has produced widespread suckers in the woodland floor. Other introduced woodland plants include Laurustinus, Japanese Honeysuckle and Stinking Iris. A large Soft Shield-fern grows close to the central path. On the eastern side of the wooded cutting, an informal swing has been hung from an overhanging oak branch and is a popular venue for local children. In the young woodland immediately behind this oak is a small area supporting native Blackthorn, which is uncommon elsewhere on the Walk. This compartment, with around fifteen different tree species, would make another good site for a tree trail, or part of a broader nature trail.

Sub-compartment 12b runs along the top of St James’s Lane Viaduct with its great views over London. For its small area, this is one of the richest botanical sites on the whole Walk. There are few trees, other than a small, planted Laburnum, so the track way is well lit throughout. This has allowed light demanding plants like the non-native Oxford Ragwort, Greek Dock, Siberian Squill and Golden Crocus to thrive, together with native Gorse and a range of grasses. The brickwork of the viaduct supports plentiful Butterfly-bush and Virginia Creeper, together with occasional Ivy-leaved Toadflax and Yellow Corydalis. A rare rose hybrid (the cross between  Dog-rose and Sweet-briar) has been expertly named, and a vigorous colony of the Glabrous-headed Hawkweed grows on top of the western wall. This, the only hawkweed colony now found on the Walk, has been known from here for more than thirty years.

Sub-compartment 12c, themost northerly on the Walk, is densely wooded, with plentiful Sycamore, Ash, and Elder. There is also a large Black Italian Poplar and the tallest Wych Elm on the Walk. Close to the boundary railings that separate the Walk from Muswell Hill, is a fine mature Pillar Apple, which produces copious crab apples in the late summer, and colours well in the autumn. Nearby is a self-sown Hairy Cockspurthorn, found by the TCV is the only example on the Walk and very rare elsewhere in the borough. The Remote Sedge, mentioned in the 2010 Plan, was not refound, and the sub-compartment now seems too dry for it.

The scrubby slope to the north, between the access path and the railings separating the sub-compartment from Muswell Hill, should be strimmed annually in September (avoiding damage to the Cockspurthorn), to encourage the development of a more diverse flora.

Acknowledgements

I am grateful to the Friends of the Parkland Walk for initiating and funding this project. In particular, I would like to thank Simon Olley for advice, encouragement and patience during the course of the project. The survey was based on maps prepared by Jon Riley for the Ecological Consultancy, and I am grateful to him and the Consultancy for permission to use these maps. All users of the Walk owe a large debt to David Hope (my predecessor and London’s first borough conservation officer), for his early work in setting up the Parkland Walk in the early 1980s, and planting so many of the trees that still grace it today. My successor Ian Holt, Haringey’s current “conservation officer”, has provided much helpful support during the project. David Solomon and Maria Precedo provided invaluable assistance during the fieldwork. Their energy and enthusiasm was greatly appreciated. Clif Osborne, (Trust for Conservation Volunteers) drew my attention to a plant of Sulphur Cinquefoil, and Mary Hogan told me about the Broad-leaved Everlasting Pea.in 3a. Roger Maskew, the BSBI rose referee, kindly identified a number of rose hybrids. I am also most grateful to Dr David Corcoran for technical help in assembling this report. Finally, I am grateful to my wife Barbara for much invaluable proof reading and for putting up with my long absences from home during the fieldwork. 

References

BEVAN, D. 1984. A Preliminary Flora of the Parkland Walk 1981-1983. Appendix 1       In The Ecology of Open Space in Haringey. Haringey Wildlife Group.

BEVAN, D. 2011. Coppicing Haringey’s ancient woodlands. Lond. Nat.90: 55-81

DAVIES, R. and BEVAN, D. 2006. Rails to the People’s Palace and The Parkland          Walk. Hornsey Historical Society.

KENNEDY, C. E. I. and SOUTHWOOD, T. R. E. 1984. The number of species of          insect associated with British trees: a re-analysis. Journal of Animal Ecology,          53: 455-478.

KENT, D. H. 1975. The Historical Flora of Middlesex. The Ray Society, London.

KENT, D. H. 2000. Flora of Middlesex. A supplement to The Historical Flora of    Middlesex. The Ray Society, London.

RILEY, J. 2010. Parkland Walk Conservation Management Plan. Ecology             Consultancy

STACE, C. A. 2010. New flora of the British Isles. Ed. 3. Cambridge University    Press.

STACE, C. A. and CRAWLEY, M. J. 2015. Alien Plants. William Collins.