Buckinghamshire: Milton Keynes Urban Flowerscape (Bletchley-Walton Hall)

2 August 2011     OS Landranger 152 (but more helpful to download official Milton Keynes map)

Length: 3-4 hours

This walk covers both native and introduced species to be found within the built-up area of Milton Keynes, including many waterside plants, with a few special species, most notably greater dodder Cuscuta europaea.

We started our walk at Bletchley railway station.  Parking here after 10am is only £2-70 all day, which leaves plenty of time to reach the furthest extent of the walk (and lunch) by midday.  This gave us a chance to look at ruderal species growing near the railway.  (Alternatively the walk can be shortened by starting at Fenny Stratford station, avoiding a rather tedious and traffic-dominated walk between the two stations.)

At the edge of the car-park we could see a number of species on the stony track-sides, lots of common toadflax Linaria vulgaris, sticky groundsel Senecio viscosus, great mullein Verbascum thapsus, wild mignonette Reseda lutea, field horsetail Equisetum arvense, buddleia Buddleja davidii and bristly ox-tongue Picris echioides.  The latter became known locally as “Milton Keynes weed” when it grew abundantly on disturbed ground during the construction of the new town.  We found it is still a major feature of rough land, although not now as abundant, with brownfield areas becoming increasingly grassed over.  

Sticky groundsel

Bristly ox-tongue

Also growing by the railway were small toadflax Chaenorhinum minus, prickly lettuce Lactuca serriola, and tansy Tanacetum vulgare.

Tansy

Walking south past the station we passed a small car-park with a fringe of plants which included, surprisingly, wood small-reed Calamagrostis epigejos, and not so surprisingly Oxford ragwort Senecio squalidus.  The latter, as is well known, is a Mediterranean species that spread from Oxford Botanic Gardens largely along main railway-lines and is now common all over the country, although still with a predilection for the vicinity of railways.  It has a laxer flower cluster, not flat-topped like common ragwort.  Here it was supporting both cinnabar moth caterpillars and a fungus Albugo tragopogonis which forms whitish blisters on various parts of the plant, especially, we found, on the undersides of the leaves.  This “white blister” is common on goat’s-beard and certain other composite species, but among the ragworts is largely peculiar to S. squalidus (which provides an additional feature for separating it from S. jacobaea in the field).

Oxford ragwort

We followed signs to the Brunel Centre and then went north from there through the bus-station, which leads to a walkway (with which Milton Keynes is usefully and famously well-provided) beside the dual carriageway Saxon Street.  We followed this all the way to the former Roman road of Watling Street.  Only a few patches of wasteland flora remained along here, but we saw wall barley Hordeum murinum, blue fleabane Erigeron acer and Canadian fleabane Conyza canadensis and even a hedge sparrow in the planted shrubberies.  Ripe fruit was falling from planted cherry-plums Prunus cerasifera, a common feature along much of the walk – it is a waste that these are not collected for eating or cooking.

We turned east along Watling Street, where the walkway eventually joins the older streets of Fenny Stratford.  When we reached the Grand Union Canal, busy with barges, we descended on the right hand side to the towpath and then went north along here to a lock.  

Barges on the Grand Union Canal

Lock

All of a sudden we were transported to a much more relaxed environment and we could gradually put the incessant traffic behind us.  It was sufficiently peaceful for a heron to choose to fish from the towpath! 

Heron by canal

Along the banks of the canal we saw gipsywort Lycopus europaeus, common skullcap Scutellaria galericulata, and a bur-marigold which appeared to be London bur-marigold Bidens connata, which has spread extensively from London along canals like this one.  (The season was too early for the seeds of this plant which would be ideal for confirmation.)

Gipsywort

Common skullcap

London bur-marigold

Near the lock we took a footpath to the right signed towards Caldecotte Lake.  This crossed through rough grassland with tall plants like mugwort Artemisia vulgaris, wild carrot Daucus carota, teasel Dipsacus fullonum, tansy and hemlock Conium maculatum. 

Wild carrot

Among other butterflies common blues flew over their foodplants, common and narrow-leaved bird’s-foot trefoils Lorus corniculatus and L. tenuis (the latter not a common plant in Bucks) where the vegetation was lower. 

Hedge brown on yarrow

By a stream at the far end of this field were clumps of Indian balsam Impatiens balsamifera.  While this is infamous for swamping out native vegetation, here it was in limited patches and native plants were holding their own (common club-rush Schoenoplectus lacustris, reed sweet-grass Glyceria maxima) – sometimes themselves dominating large areas, so there would seem to be no particular reason to be concerned about the presence of the exotic balsam here, especially as it provides welcome colour and interest. Most of the green spaces in Milton Keynes are in any case dominated by planted shrubs that allow no native vegetation to survive beneath their dense cover.  In the stream was much yellow water-lily Nuphar lutea, already having formed many of the “brandy-bottle” shaped fruits that gave rise to one of its traditional English names.

Stream with balsam and club-rush

Indian balsam

Common club-rush

Passing under a major road the path bent north through a wood with young planted aspens Populus tremula with the associated leaf-gall of the mite Phyllocoptes populi.  There was soon a path off to the right to the edge of Caldecotte Lake at its southern end.  This lake was constructed as a balancing lake for controlling flooding of the River Ouzel.

The waterside vegetation included marsh woundwort Stachys palustris, water mint Mentha aquatica, purple loosestrife Lythrum salicaria, meadowsweet Filipendula ulmaria, water dock Rumex hydrolapathum, wild angelica Angelica sylvestris, great willowherb Epilobium hirsutum, yellow iris Iris pseudacorus (many with straight white linear leaf-mines of the agromyzid fly Cerodontha iraeos), creeping forget-me-not Myosotis secunda, and the sparse umbels of stone parsley Sison amomum, a plant so slight that it seems to disappear as you look at it.  

Marsh woundwort

Purple loosestrife

Stone parsley

More exotic colour was lent by frequent orange balsam Impatiens capensis.  

Orange balsam

There were also planted exotic shrubs at the water’s edge – Japanese rose Rosa rugosa, and very frequent white-berried red osier dogwood Cornus sericea which seemed to have been one of the local authority’s favourites, so frequently has it been planted around here (and seemingly spreading). 

Japanese rose

Red osier dogwood

Common blue damselflies Enallagma cyathigerum were mating here, the bright blue male and mostly dull black female, and the occasional reed bunting showed itself. 

Common blue damselflies mating

A section of the wide grassy bank closest to the lake was left uncut, allowing a diverse plant assemblage which included lady’s bestraw Galium verum, quaking-grass Briza media, red bartsia Odontites vernus, heath groundsel Senecio sylvaticus, field scabious Knautia arvensis, cowslips Primula veris and smaller cat’s-tail Phleum bertolonii in a confusing mixture of lime- and acid-loving plants typical of engineered landscapes that mix soils and stone of miscellaneous origin.  A somewhat slim-headed knapweed rife here was the chalk knapweed Centaurea debeauxii.  

Chalk knapweed

Six-spot burnet moths and immigrant hoverflies Scaeva pyrastri, readily identified by their white crescents on a black abdomen, were flying among the flowers. 

Six-spot burnet on field scabious

On the lake were mute swans with well-grown grey cygnets, cormorants and great crested grebes diving for fish, pochard, coots, moorhen, mallard, black-headed and herring gulls.

Mute swans & cygnets

The waterside path eventually led under a main road, Bletcham Way, to continue alongside the northern section of the lake, busier here with boating and a hotel complex.  Greylag and Canada geese were concentrated here on the lake, and pied wagtails ashore. 

Greylag goose

Having rounded a peninsula the path doubled back northwards again and over a weir, after which it divides, the right-hand path continuing along the northern shore of the lake.  Here we took the left-hand path and left the waterside, crossing Simpson Road
at a small car-park and continuing on the other side along what was signed as the Ouzel Valley Walk.  The path keeps close to the west bank of the River Ouzel.  Here new water-plants were evident, such as arrowhead Sagittaria sagittifolia, unmistakable with its large arrow-shaped leaves, and spikes of white three-petalled flowers which place it in the water-plantain family Alismataceae; water chickweed Myosoton aquaticum, with its unpleasantly sticky stems; water figwort Scrophularia auriculata with strongly-winged stems; great yellow-cress Rorippa amphibia; and flowering rush Butomus umbellatus. 

Arrowhead

Water chickweed

There were more dragonflies here too, including brown hawker and the well-named beautiful demoiselle.  The most exciting discovery for us, however, came just before we were about to cross the river into Walton Hall.  It was the first time we had found the elusive greater dodder Cuscuta europaea.  We were of course familiar with the commoner dodder that mainly parasitises gorse, but here at the river’s edge its rarer relative with larger flower-heads was entwining its slim stems mainly around common nettle Urtica dioica, but also occasionally hedge bindweed Calystegia sepium, which itself was also twisting around other plants.

Greater dodder

We then crossed a small bridge into the Walton Hall district (former landed estate now the campus of the Open University) and approached the church of St Michael’s, in front of which stood a tall, wide-spreading walnut Juglans regia of some local renown, although the girth of its trunk did not indicate any great age.  Nevertheless, it seems to have given its name to the nearby “Walnut Tree Estate” and various businesses like “Walnut Pet Supplies”.  Its leaves were infested by many galls of the mite Aceria erineus. 

Walnut fruit and leaf-galls

The churchyard included several recent graves of Open University academics and staff, but the church, which existed as long ago as 1225, is now deconsecrated. 

St Michael’s Church

Across the road from the church and a little further west is a pond with many colourful garden plants around it, although the native water-plantain Alisma plantago-aquatica was still in evidence.  At the far end of this pond, just after a young red horse-chestnut, stands an example of the Aylesbury prune Prunus domestica cultivar (see our walk on 30 June 2011 which featured this old orchard-tree).  By now the fruits were ripe and purple, but the flesh, and especially the skin, was rather bitter, confirming its traditional use as a cooking plum.

Going directly north from the pond we came to a green in front of the Open University’s refectory.  The first of several trees here was an old mulberry Morus nigra, its five main boughs having to be supported by wooden posts.  The ground was spattered with its fallen black fruits.  Although beautiful to eat, picking tended to involve them spurting blood-like red juice all over our hands and arms! 

Mulberry tree

Mulberries

Other younger trees on this green are a tulip tree, a copper beech, and a cherry.  The refectory is a clean light place to obtain healthy and innovative cafeteria-style meals and good coffee, as we had now reached the ultimate point of the walk.  As we left we noticed a new wood sculpture, made in 2010 by Tom Harvey, carved out of a very large stump of an old cedar tree, with a tree motif (presumably the Tree of Knowledge).  On the back of the trunk is carved a fox chasing three hares carved separately on the back of a nearby bench, presumably carved out of a large fallen bough of the same old tree.

We continued south down the road, Walton Drive, carefully stepping over a wandering devil’s coach-horse beetle Staphylinus olens, and crossed the Groveway by means of an underpass, the path continuing around the edge of a field with black nightshade Solanum nigrum until it brought us back across Simpson Road to the north-east corner of North Caldecott Lake.

Caldecotte Lake

We walked the whole of the east side.  Here we added branched bur-reed Sparganium erectum to our list of waterside plants. 

Branched bur-reed

Rather circuitously this path eventually leads back under Bletcham Way (see earlier).  Here steps on the left led back up to a walkway beside the road and we were able to return to the west side of the lake and repeat our morning’s walk back to Bletchley station.  It is possible to continue along the eastern side of South Caldecotte Lake, but this includes a built-up section and we suspected was probably not worth the extra distance.  There are bird hides on the southern shore but these are more likely to be of use in the winter.