… a guest blog by Dr Chris Gibson, Co-author of British & Irish Wildflowers and Plants: A Pocket Guide, who recently led a Wildflower Walk at Canvey Wick.
As a prelude to my walks in Hockley Woods, I took the opportunity while in south Essex to reacquaint myself with some of the sites and botanical sights of my now quite distant past, going back to the 1980s.
Canvey Wick, a remarkable brownfield wildlife site on a former oil refinery has appeared in these blogs before, as one of the greatest success stories of my conservation career. I have described it as an ‘accidental nature reserve’ that has now transformed into a real nature reserve, owned by the Land Trust, and managed by Buglife (the charity of choice of #WildEssex) and RSPB.
A site of such resonance to me, one I have been associated with for more than 25 years since we discovered its remarkable biodiversity, I was thrilled to be asked to lead a wildflower walk around it for Buglife last week. It has always been seen as a reserve especially for invertebrates. When discovered, it was believed to have almost the greatest concentration of rare and scarce invertebrates of any site in the country, second only to the much larger Dungeness. It helped to put brownfield nature on the conservation map.
The reasons for that diversity are manyfold, mostly relating to its use (and abuse) by humans over the last eighty years. But another factor is the diversity of wild plants it holds. As with all brownfield sites, the plants are a wonderful multicultural mix from across the world, native species including many Essex coastal specialities and non-natives derived from gardens and port activities etc.
So an ideal area to look at wild flowers and in doing so to introduce people to our newly published book, which makes no distinction between natives and aliens. If a plant is found in the wild, irrespective of its status, in more than a third of the 10km squares of the National Grid, it is in the book.
While conservationists may despair about the spread of non-natives, in many cases they are not aggressive, and often they perform useful ecological functions, as any gardener knows. So we looked at Narrow-leaved Ragwort, which has a nearly year-round flowering season, so providing nectar and pollen for insects even at seasons when natives are not up to the job.
Other non-natives included Goat’s-rue, Broad-leaved Everlasting Pea and Hybrid Bladder-senna, all loved by bumblebees, plus Rose Campion and many others.
Then there are the non-native natives! Sea Buckthorn, a natural plant of sand dunes elsewhere but not in Essex, is very useful in autumn for birds that feed on its orange berries. However it is also a very aggressive species that shades out other plants, native and non-native alike, reducing biodiversity. Other less contentious native coastal specialities included Narrow-leaved Bird’s-foot-trefoil, Sea Club-rush, Wild Carrot and Grass Vetchling (a real favourite of mine).
The beauty of brownfields is that they contain plants (and, by extension, insects) from a wide range of natural habitats, including here a mix of drought-tolerant succulents (e.g. Biting Stonecrop) and chalkland specialities, like Dogwood and Yellow-wort, alongside Tufted Vetch and Perforate St. John’s-wort, characteristic of clayland soils.
And on top of all of these there are the orchids, good colonisers of bare and grassy habitats by virtue of their dust-like seeds. Common Spotted, Pyramidal and Bee Orchids were all in flower, although the latter were going over. Since I first knew Canvey Wick nearly 30 years ago (before we even coined its name) the Pyramidal Orchids have certainly increased, while Southern Marsh-orchids have declined hugely … once the commonest species, last week we saw none.
Of course things always change, especially on developing habitats such as here, so this is not surprising. But changes do need to be managed: while this site has rewilded itself over the past half-century, that wilding now needs to be tempered in the absence of agents of disturbance – Wild Boar, Beavers, Bison or boys on bikes. Thus, aggressive Sea Buckthorn needs removing and indeed the developing Birch woodland needs to be broken up to allow light in again. Fortunately the reserve managers are aware and undertaking these essential tasks.
Aside from the plants, there were Cuckoos calling and Cetti’s Warblers singing, while a Fox trotted along one of the relict roadways; too breezy for many invertebrates but they did include a Vapourer Moth caterpillar, a bumblebee-mimicking Furry Drone-fly and my first Scarce Emerald damselfly of the year.
While visiting Canvey I also took the opportunity to search out and photograph some of the scarce plants of southern Essex that are not in the new book, for the forthcoming three-volume set covering all wild plants of Britain & Ireland. Some were easy as they are locally frequent: for example on Belton Hills, Leigh-on-Sea, it was Bithynian Vetch. This is a generally uncommon plant of cliff-slope grassland, as here, and although not fully in flower, there was plenty of scope to capture its key features such as the large stipules with jagged lobes.
Alongside there was growing more Grass Vetchling and Common Agrimony, together with a very interesting Tragopogon that I am still not sure of. With purplish flowers it should be Salsify, but the colour is a little too pink for comfort and there is that sunset-yellow suffusion in the centre of the flowerhead. A hybrid between Salsify and Goat’s-beard is therefore one option. But what about those yellow tips to the ‘petals’? That reminds me of the southern European plant I am so familiar with from Mediterranean travels Tragopogon crocifolius, except that has a more chocolate-brown hue overall…. So my mental jury is still out: any ideas anyone?
A little to the west along the London Clay former cliff-line is Hadleigh Castle Country Park, the South Benfleet section of which is also renowned for unusual plants, as well as regular fly-pasts of squawking Mediterranean Gulls. That site provided me with yet more Grass Vetchling (seems to be having a fantastic year – or have I just caught its magical three-weeks of cerise apparency in full flow?) together with Nipplewort, Tree Mallow, Corky-fruited Water-dropwort (a very rare plant when I used to work these parts, now on every nature reserve, probably spread on shared mowing kit) and Hairy Buttercup, another speciality of coastal grassland and a glorious array of flowering grasses, here Crested Dog’s-tail and Italian Rye-grass.
That just leaves the local star that is Hairy Vetchling. Generally considered not to be native in Britain, it does have some claim to that status at least at this site having been known here for at least three centuries. Again this seems much more frequent than when I worked in the area: the park managers are clearly doing something right!
But you cannot win them all. There is another plant with a similar tenuous claim to native status from these slopes, the umbellifer Hartwort. I knew it well in past times, but could find no trace on this occasion.
Then finally it was back onto Canvey Island to try and hunt down a plant that was first found in Essex as recently as June 2023. I had a precise location (above), and found several other unusual species such as Knotted Hedge-parsley and Water Bent, but it took a long while to find the weakly scrambling, mini-Cleavers that is Galium murale, or Yellow Bedstraw or Small Goose-grass…. It is a native of the Mediterranean, first found here a year ago, then subsequently in Rayleigh and probably Bardfield. Indeed it is almost certainly overlooked elsewhere, with its diminutive stature and, even when you have found it, the tiny, unassuming pale yellow flowers. But under a lens those flowers and the long, hairy sausage-shaped fruits are unmistakeable. Honestly!
Buglife acknowledges that some non-native species of plant can benefit native wildlife by providing services such as food and shelter. However, we advise caution as non-native species can negatively impact native flora and fauna, especially if they become invasive. Invasive non-native species are major contributors to global biodiversity decline, causing extinctions, reducing biodiversity, competing for resources, and altering habitats.
While some non-native species may initially seem harmless, they can become invasive if conditions change. Therefore, attention is essential when dealing with them. Buglife promotes the use of locally grown and native plants to support native fauna and prevent invasive species from entering the UK through horticultural trade.
