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This March marks the 15th anniversary of the death of Robert Adrian de Jauralde Hart, a man who quietly, and without outside recognition for much of his life, created a garden that was at once cutting edge but also rooted in ancient traditions and techniques. Hart was a pioneer in temperate forest gardening, and spent 40 years creating and tending to his eighth of an acre plot in Wenlock Edge, Shropshire.
Hart had initially set out to make a traditional smallholding, with orderly beds of vegetables, a small orchard and assorted livestock. His aim was to provide healthy, health-giving food for him and his brother Lacon, who was born with severe learning difficulties and for whom Hart was the primary carer. Realising that the combined challenges of the smallholding and his responsibilities towards his brother were beyond him, he observed a planting of herbs and perennial vegetables in one corner of the smallholding that seemed to thrive in spite of a lack of intervention. Taking these observations further, Hart gradually converted the entire orchard into a forest garden, establishing one of the first prototypes for temperate climates.
The principles of forest gardening are as ancient as the notion of cultivating plants for food. It is an agroforestry system, comprised of planted layers with large trees at the apex and small, ground-covering herbs at the base. The spiritual descendants of ancient forest gardens can still be found across the world, in the “home gardens” of Kerala, Zambia and Nepal. There are Kandyan forest gardens in Sri Lanka, huertos familiares (family orchards) in Mexico and pekarangan (complete gardens or gardens of complete design) in Java.
The development of the Chagga home gardens on the slopes of Mount Kilimanjaro in Tanzania provide an insight into how ancient humans may have created the first forest gardens. Over thousands of years various tribes migrated to the once forested slopes of Kilimanjaro to take advantage of the cooler climate and good growing conditions, to the extent that now the area is one of the most densely populated in Tanzania. Historians have long postulated that our prehistoric ancestors would have identified the most useful food plants in the forest, protected them and then worked to exclude unwanted competing vegetation from around them. Over time, as the most productive forms of each plant came to light, these would have grown in favour of inferior “varieties”. Eventually, useful plants from neighbouring regions would have been introduced into these proto-gardens. This is the process that the Chagga gardens have grown from, and today they extend to about 120,000 hectares, located mainly between 900 and 1,900 metres above sea level.
It is a system of beautiful simplicity, and the Chagga gardens are filled with plants with purpose, if rather chaotically organised. The cropping system is intensive, with not an inch of growing space wasted, but unlike western monoculture techniques this — and all forest garden systems — promote polyculture; a large number of species represented by multiple varieties.
There are at least 15 different species of banana (Musa) under cultivation, and woody trees in variety to provide foliage fodder for livestock and timber for making stock-proof fencing, shelters and so on (the leaves and pseudostems of the banana are also used for fodder). The Chagga have an intimate knowledge of the characteristics of each plant and how to use it, when to thin the canopy of the trees to allow more light to the understorey and which plants are most useful in battling pest infestations. Papaya (Carica papaya) is valued for its fruit but also as a mosquito repellent, the poisonous Datura arborea is an excellent forage plant for bees and has anti-nematode properties, while Markhamia platycalyx provides building poles that contain termite-repellent tannins. These trees and larger shrubs provide shade for growing coffee (Coffea arabica), the surplus of which is sold as a cash crop along with spare bananas and cardamom (Elettaria cardamomum). At the lowest level is a wide variety of food plants including sweet potato (Ipomoea batatas), eggplant (Solanum melongena) and yam (Dioscorea spp).
Hart’s system for temperate forest gardens is based on the observation that the natural forest functions in distinct layers, in exactly the same way as the Chagga gardens. Hart developed this further and codified it into the “seven-layer” system: a canopy layer of mature trees; a low-tree layer comprised of nut bearing and fruiting trees; and a shrub layer of fruit bushes like raspberry and currant. Beneath these woody layers are the herbaceous layer of perennial herbs and vegetables; a rhizosphere layer of underground, usually tuberous plants; and a ground-cover layer of edible plants that spread horizontally. Lastly, a vertical layer is comprised of climbing plants and vines that use the tree layers as supports or that can be trained on to a system of poles and wires.
An essential aspect of the seven-layer system is that unlike conventional vegetable gardens, where full sun is a requirement for many of the plants to thrive, Hart’s forest garden ideas focused on shade-tolerant plants.
I have been visiting Rachel Benson and Martin Baker’s forest garden at Old Sleningford Farm in North Yorkshire since it was first set out a decade ago. The initial clearance and cultivation of the two-acre site was carried out in the traditional way using pigs, which are capable of rooting out pernicious, deep-set weed species such as dock and bramble, leaving soil that is clear of weeds and turned over to a snout’s depth or more. With no existing mature trees to form the apex layer, Benson and Baker opted to exclude them and go straight for the low-fruiting trees instead, planting these and the fruit-bush layer through the autumn of 2004 through to spring 2005. Mulching with cardboard and well-rotted manure was then followed with fermenting cattle fodder and straw in order to exclude light (preventing weed seed germination) and to feed the soil from above. Planting of the herbaceous perennial layer and ground-covering plants followed before another round of fruit-bush planting.
The planting eventually extended to five phases, each building on the last and all followed by extensive mulching with organic matter. In the early days, while the fruit trees and bushes were still relatively small, the ground-covering plants and perennial vegetables romped away. Dense carpets of such delicacies as alpine strawberry (Fragaria vesca) and buckler-leaved sorrel (Rumex scutatus — a diminutive salad leaf with a sharp tang like cooking apple skin) covered the ground. Today they have been reduced to smaller colonies as the tree and shrub layer have closed in around them. The experience of wandering into a forest garden like the one at Old Sleningford is unique. It has the familiarity of woodland, but one in which everything is edible. Apple and pear trees are loaded with fruit; and these are not dull-flavoured supermarket forms but flavour-packed heritage varieties. Kiwi fruit, hops and culinary vines wind along support wires and up into the tree canopy. In a clearing, a huge Japanese wineberry (Rubus phoenicolasius) almost fills the space with its peculiar, red-furred stems. Hart’s diet was about 95 per cent raw food, harvested from his forest garden, and it is easy to see why; there is a bountifulness, even in winter, that is absent in traditional “allotment-style” gardens.
Hart wasn’t a lone idealist. His ideas have helped to inspire the work of leading figures in sustainable food production, including Martin Crawford, of the Agroforestry Research Trust, and Ken Fern, founder of the charity Plants For A Future. Hart’s seven-layer system has been adopted as one of the key components of permaculture. From an idea as ancient as the Garden of Eden, a new line of research and practice has been born that can be applied to spaces no bigger than a small domestic garden, and which could make a significant contribution to future food security.
Matthew Wilson is managing director of Clifton Nurseries in London
Photographs: Ulrich Doering/Alamy; Jake Lyell/Alamy; Danita Delimont/Alamy; Rachel Benson; Howard Rice/Gap Gardens; Matthew Wakem/Robert Harding