In meteorological terms, we are welcoming spring and turning our backs on winter. In reality, the latter seems reluctant to leave the party. Cold nights, more frosts, driving rain and sleet pepper the early days of the month. With the lowest temperature of -16°C recorded in Sutherland, Scotland, rose a stunning orange ‘worm’ moon, named by native Americans for its association with the first appearance of worm casts on the warming spring soil. The worms at Knepp may have to wait a little longer to emerge.
The garden is still in transition. Perennial green leaves tentatively push through their deadened winter crowns, buds form on cinnamon-brown woody stems of shrubs, reticent to open. We continue to balance the brown-to-green ratios, surveying the ecosystem and our ‘limits of acceptable change’, keeping as much upright winter structure for as long as possible, extending the life of dry habitats for insects, and food for passerine and native birds beginning to nest. There is a rush to finish the pruning and tying-in of established climbers and setting the stems of newer plantings on a generously-spaced trajectory. By attaching them to horizontal wires and ‘browsing’ (or cutting back, in the absence of herbivore teeth) lateral stems, the plant is encouraged to be more abundant in flower; providing ample nectar and pollen in summer, winter hips and berries, and level, sheltered nesting spots. Long-tailed tits build complex nests early despite not laying eggs until April; robins and blackbirds start breeding in March. We have sent ducks skyward in startled flurries as we enter the garden, interrupting their perusal of potential sites to start a family.
According to the British Trust for Ornithology, many species are now breeding up to 31 days earlier than they were in the 1960’s. Climate change is the main driver and can often cause imbalance in the ecosystem where chicks are hatching before insects and going hungry. We have endeavoured to fill some of the ‘hungry gaps’ for insects in the garden with 5,000 or so spring and early summer-flowering bulbs, planted back in early winter. Crocus and deep-blue dwarf iris emerged in late January, and we are still enjoying the hoop petticoat daffodil (Narcissus bulbocodium). Various species tulips are springing up one after another in drifts: the cheerful pink, low-growing tulip (Tulipa humilis), the Turkestan tulip (Tulipa turkestanica), and the lemon-scented yellow flowers of wild tulip (Tulipa sylvestris).
Wild tulip, dwarf iris, hoop petticoat daffodil, and low-growing tulip in the rewilded pool garden.
In the same spirit, with the help of the brilliant Knepp volunteer group, we added another 600 late- summer flowering bulbs for the time of year when most plants have bloomed and gone to seed: society garlic (Tulbaghia violacea) amongst the grasses by the pool; white spires of summer hyacinth (Galtonia candicans) scattered around the bowl of the ephemeral pond; two-coloured pineapple lily (Eucomis bicolour); white and pink species of Bowden lily, their blooms held on erect clear stems into October; and the trumpet-shaped swamp lily (Crinum x powellii). All these bulbous perennials are native to South Africa and need plenty of sunlight and free-draining conditions. They can often rot if subjected to extreme wet or frozen conditions in moist soils. So, we plant in spring to give them a chance to establish as the temperatures rise and, if last year is anything to go by, they will thrive in the hotter, drier summers the UK seems increasingly prone to.
On the other end of the weather spectrum, the lengthy periods of frost over the winter have left us with many plants either dead or significantly stunted – the spurges and rock roses particularly hard hit. Our discussions have turned to the horticultural attitude towards death in the garden. In nature a plant may die from reaching old age, being over-browsed or trampled by animals, struck down by weather, insect attack, disease or fungi. Their stems and leaves drop to the ground over time. They slowly decompose, feeding the soil and all its biota, which in turn feed the growth of seeds and plants in a natural cycle. Our instinct as gardeners is to tidy away the dead, to erase what might be considered unsightly – particularly larger woody shrubs. Yet often, gardens can be populated with freestanding sculptures or obelisks as aesthetically pleasing upright structures – not unlike the skeletons of the dead shrubs in the garden with a little creative trimming? In the case of recognisable diseases or fungi that cause widespread destruction such as honey fungus it is, of course, advisable to remove and burn the dead material. But we decided to keep what was architectural, lightly pruning some, cutting back some to the base, maintaining as much complexity as possible. With an enormous Pasteur spurge (Euphorbia x pasteurii), we ‘lifted’ the shrub by taking out some of the lower stems to create a giant umbel shape and encouraged some of the more bedraggled leaves to part with their limbs with some gentle shaking. In the space left underneath, we planted two climbing hops, ‘ Wye Challenger’. Their large lemony-green palmate leaves will scramble all over the structure, growing five metres into adulthood and bearing hanging flowers like large insect pupae. They can be used as bittering and flavouring in beer brewing or dried for teas or treatments for insomnia. Even the bines (new shoots pushed up in spring), can be eaten as asparagus substitutes. The remaining area was perfect clear ground for a dense clump of foxtail lilies (Eremurus stenophyllus). Their strange octopus-like fleshy roots sometimes reach 50cm wide, and need to be planted in shallow, free-draining soil. Since there was little else growing under the canopy of the euphorbia when it was alive, and they begrudge competition or disturbance, this section of the rewilded garden with topsoil under 50mm of coarse sand was ideal.
The dead stems of the Pasteur spurge in the rewilded pool garden, before and after some sculpting.
The close of the month saw us driving up to Kew Gardens where the London Garden Network were holding their seminar ‘Under the Canopy – Future-proofing Green Spaces’. Charlie had been asked to join one of the panel discussions. The day began with Dr John Grimshaw, curator and director of the Yorkshire Arboretum. Having worked in Tanzania and been at the coalface, witnessing the effects of climate change up close, his message was clear: with the projected 3°C temperature rise in London by 2050, the time to start repopulating the canopy trees of the city is now. The wonderful mature plane trees (Platanus x hispanica), tolerant of pollution, that give shade, humidity and grandeur to so many famous squares and streets, are all of an age. Planted widely in the 18th and 19th centuries they are now threatened with a fungus called ‘plane tree wilt’. Global trade has led to the introduction of fatal pests and diseases that are affecting the health of even common trees in woodlands, parks and gardens across the country. He is on a mission to educate the gardeners of today in the sort of planting choices that will survive extremes of heat and rainfall, looking to southern Europe, trees native to the Balkans and some temperate forests in the USA. Sadly, many of our native trees will not reach their full potential in the face of these dual threats. From Errol Fernandes’ micro forest in the grounds of the Horniman Museum, to Charlotte Harris’ design of London’s first 1.4-acre urban forest rooftop, and Navdeep Deol from the Heston Action Group – with their community green space and tree champion projects – the issues, and some of the solutions are clear. The responsibility, as well as the capability of all guardians of nature is to plan and plant with sustainability at the heart of decision making. Re-using on-site materials, using water as a precious resource, engaging communities and making informed plant choices are all within our powers. Sharing stories and good practice is a positive way to begin, and to continue.
While the memory of snow showers is still fresh, and we dream of the slanting sun of warm evenings it is important to remember to treasure what we have now and ensure our grandchildren can enjoy the same pleasures in their old age.
Moy Fierheller Deputy Head Gardener March 2023
What we are reading;
https://youtu.be/fOeNo2SxYcc John Little – Designing in Complexity