Other unplanned plants were making their presence known in the garden with similar degrees of success. These are the wildflowers that piggy-backed into the garden amongst the plants brought in from nurseries, flew in over the walls with birds or on the wind, or hid in the crushed concrete and sand we brought in from the demolished estate farm buildings that became the Rewilded Garden. Charlie has compiled a compendium of all these uninvited newcomers, with a view to giving form to our management of them, creating a grazing index. Some of these plants have immense ecological value, such as ragwort (Senecio jacobaea). It is one of the most visited flowers by butterflies and moths, and more than 200 invertebrates have been recorded on it according to the Wildlife Trust. The orange-and-black-striped cinnabar moth caterpillars, like Alice in Wonderland characters, can be seen feasting on them in abundance in early summer.  Some of these wildflowers serve specialists such as the larvae of the orange tip butterfly that lays its eggs on cuckoo flower, garlic and hedge mustard (Cardamine pratensis, Alliaria petiolaris, Sisymbrium officinale). On the grazing index both ragwort and garlic mustard are in mid and low categories, meaning we only weed them out if they are significantly restricting another plant.

Canadian fleabane (Conyza canadensis), on the other hand, is high on the index. We remove it wherever we see it. An annual plant of fields, roadsides and wastelands, originally from Asia, it is reputed to have been sent here in the 1800’s by taxidermists. The fluffy seed heads were used to stuff bird skins. Each flower head might contain as many as 70 seeds and the average number per plant ranges from 25,000 to 60,000. We could use it in the Kitchen Garden, as the young leaves and shoots are edible when cooked. But since it flowers and sets seed rapidly, even in juvenile form, it will quickly outrun us and out-compete slower-growing species. Its basal rosette also covers bare ground, preventing other plants from self-seeding.

This year, scentless mayweed (Tripleurospermum inodorum) is also on high graze. We left them to grow last summer while the new plants and seedlings were establishing themselves, their white daisy flowers and pleasing dome-shaped habit filling spaces and flower droughts. Like many plants in the chamomile family it both hosts insects and is a source of nectar and pollen and, when we take out larger plants, beetles and small insects are to be found hiding in its shade. But it is a pioneer species that produces a large number of seeds from each flower head and remains viable for many years in soil. We can be fairly certain that even with a high level of purging, plenty of seedlings will reappear next spring. Our roles as proxy landscape engineers and our selective herbivory are always trying to stand in the middle of the see-saw, attempting to balance the tipping points between monoculture and ecological value.