Wilding the Garden
July 2024
For July, it is a rare and curious sight amongst the froth of elderflower and yarrow to see swags of white trumpet flowers festooning the hedgerows, like wedding decorations. Bindweed has been the undoubted winner in wild and ornamental settings with this year’s exceptional rainfall. Moss and fern-green is the predominant shade of the verges replacing the bleached wheat and oat hues we’ve become accustomed to at this time of year. The brief warmth in June was short-lived. The jet stream has pressured its way into our latitude again. Although the temperature hovers around 18°C, the sun is secreted behind sullen, bruised clouds like the insides of muscle shells.
The gloom coincides with some alarming days of silence in the garden and, on further enquiry, in the rewilded Southern Block at Knepp too. Very few insects. The last two summers when entering the garden there has been a constant low thrum of beating wings, buzzing, and frenzied foraging among the flower heads. The Bumblebee Conservation Trust cites the weather as a significant factor. Foraging for nectar and pollen amongst wet petals between rain showers is arduous work and queen bees need to incubate broods in their nests for longer periods when the temperatures are low. The Trust’s prognosis however is positive – the colonies have the potential to catch up if the summer improves.
Mathew Oates, a naturalist and nature writer who guides visitors at Knepp sharing his abundant knowledge of his favourite subject, the purple emperor butterfly, has also noted the lack of insects. He mentions, in particular, the hoverflies that migrate from Africa and Europe to southern Britain annually – between 1 and 4 billion of them. He has barely seen any of the usual species which is concerning – the lack of their services as voracious aphid consumers in their larval stage and important pollinators as adults will only become apparent later in the season. He suggests we should spend time surveying ‘the larval niche’ in the winter and spring and include European weather patterns to gain more information about the impacts on migrating and resident hoverflies and other insects.
Penny Green, Knepp’s resident ecologist, set up the large moth trap in the Rewilded Garden, part of the ongoing wildlife surveying, building our own data set. We gathered expectantly first thing in the morning to see what the relatively cool night had brought to the powerful lamp. Carefully removing each egg-carton section, Penny logged the findings. The world’s earliest entomological society was formed by a group of wealthy enthusiasts in the early 1700’s in London, officially named ‘The Society of Aurelians’ in 1745. Many of their members were responsible for the fascinating, endearing and memorable common names of moths still in use today. With over 2,500 UK moths, countless of which are shades of brown and grey, they drew on the moths’ shapes, textures and markings as inspiration and their similarities to what they were surrounded by – the various uniforms of footmen, Persian carpets, wood panelling, the shapes of tussocks, weaves and types of cloth, or the face of a pug dog – a popular lady’s pet of the time. By far the most impressive specimens we spotted in the moth trap were two beautiful, bright pink-and-green small elephant hawk moths. Their Latin name Deilephila porcellus translates as ‘evening-loving piglet’ and we were particularly pleased to see them. Their larval food plants are fuchsias, galiums and willowherbs, and we have deliberately left rosebay willowherbs to proliferate, ordinarily seen as a ‘weed’, for this very reason.
Two elephant hawk moths caught in the moth trap set up in the Rewilded Garden
Other species sitting quietly in the cardboard hollows or flitting onto our T-shirts were the rosy and common (grey uniform with yellow trim) footmen, ruby tiger, yellow underwing, nut tree tussock, dunbar, flame shoulder, mint, small fan-footed wave and the impressive drinker. Sadly, moth numbers are in decline, particularly here in the south of England, down by 39% since 1968, with over fifty species becoming extinct in the 20th century. Many other species such as bats, rely on them as a food source – so bats are declining too. Gardens that link up to wider green spaces for flying insects can provide important refuges. Avoiding the use of chemicals, artificial lights and including night-scented plants like evening primrose, honeysuckle and jasmine in a garden are simple things most people can do to help. The larval stage of moths is just as important, so a change of mindset towards their food plants – the uninvited visitors to a garden such as dandelions, docks and plantain – is an easy step that can make a significant impact.
Clockwise from top; Small fan-footed wave, flame shoulder, the drinker, common footman, dunbar, nut tree tussock, yellow underwing, ruby tiger – some of the moths recorded this month in the Rewilded Garden
We’ve ranked these plants and many others in a document we call our Grazing Index. This began as an idea last spring and has grown into an expansive, working record that we’re continuously refining and discussing. It’s a system devised to guide us in our management of ‘weeds’ – those native and non-native plants that have found their own way into the garden. By scoring these plants according to a range of qualities, such as wildlife and ecological services, sensory and aesthetic properties, ease or difficulty of removal, we can be guided in the level of our interventions – whether high (hitting them hard), medium (a degree of tolerance) or low (much more relaxed). Whilst we can’t claim this is a scientific document – measuring every species accurately is very difficult and will vary in every garden – we see it as a useful tool. We now have a solid understanding between us of what to remove and why; but also, what’s missing – habitats for native plant species that provide services to certain insects that have specialist needs. And it’s become a really valuable tool with which to engage visitors in that change of mindset towards ‘weeds’.
A good example of a plant we have added to the Grazing Index this season is annual fleabane (Erigeron annuus). It is a pioneer species, inhabiting disturbed ground readily, an American native that used to be burnt or dried to ward off fleas and gnats. One pretty clump appeared last summer in the Rewilded Garden. Standing a metre high with a proliferation of small, white daisy flowers it is loved by pollinators, so we graded it ‘low’ in the Grazing Index. However, this year it has raced through the garden, having seeded plentifully in a twenty-metre radius from the parent plant. It looks delightful – a chest-high tingle of white, swaying gently amongst grasses, pink coneflowers, tall, flat-headed wild carrot and intense orange splashes of the North American butterfly weed (Asclepius tuberosa). We spent a morning thinning them out to prevent them dominating too much and impacting plant diversity in the garden overall, and wondered whether it would be good as a cut flower. Huge sprays went up to the house and proved a resounding (if short-lived) success.
Thinning annual fleabane (Erigeron annuus) in the Rewilded Garden and using it as a beautiful spray of cut flowers
So, it’s sensory score was duly recorded and adjusted, as well as a note to indicate the time of year when it begins to self-seed and the grazing regime needs to be adjusted to ‘high’.
We realised that modifying the ratings according to a plant’s behaviour at different times of the year like this is an important aspect of the Grazing Index. Germander speedwell (Veronica chamaedrys) is a valuable native in the garden for many pollinators and as a larval food. Being a creeping plant, it can act as a ground cover in spring when the previous autumn’s seed bank is just emerging. To maintain as much plant diversity as we can, we added notes on the index to clear some denser areas at that time to ensure enough bare ground to enable germination. Right now, it is ribwort plantain (Plantago lanceolata) that we’re clearing. Each flowerhead can produce up to 200 seeds, and we add a ‘high graze’ proviso for this month. A Eurasian native, it has all manner of medicinal uses, the leaves can be eaten when young, the seedheads are important food for songbirds and, again, the burnt-brown flower head ringed by a skirt of small, pale-yellow petals are perfect in cut-flower arrangements. Richard Mabey, in his invaluable book Flora Britannica, lists the plant’s other common names – fighting cocks, short bobs, soldiers and sailors, black Jacks, hard-heads and Carl doddies. They originate from children’s games – where the flowerhead on its long wiry stem is used as a substitute for conkers (it seems some plantain heads are tougher than others and can produce champion soldiers), or as a catapult. The stem is looped in a noose below the head and, when sharply pulled, the head is hurled forward like a catapulted stone. Perhaps we’ll need to add another column entitled ‘fun’ to our index.
Moy Fierheller Deputy Head Gardener July 2024
What we’re reading;
www.bumblebeeconservation.org/are-you-seeing-very-few-bumblebees-this-month/
/www.matthew-oates.co.uk/home/
www.nri.org/latest/news/2024/migrant-hoverflies-the-life-and-importance-of-these-masterful-mimics
UKMoths | Guide to the moths of Great Britain and Ireland
moth-foodplant.pdf (butterfly-conservation.org)
The State Of Britain’s Moths | Butterfly Conservation (butterfly-conservation.org)
Common names can be marvellous but do all species need them? – Douglas Boyes: Blog
Richard Mabey, Flora Britannica, pub. Chatto & Windus, London, 1997
