In 2005, David Jacke and Eric Toensmeier burst on to the permaculture scene with the publication of the two-volume bible of temperate forest gardening, Edible Forest Gardens. Not content to rest on his laurels, so to speak, Toensmeier has been keeping himself busy by writing this latest addition to the permaculture canon: the first book ever on the topic of perennial vegetables.
Perennial vegetables enjoy a number of advantages over annuals – for a start, they minimise work by not having to be planted every year, and their longer lifespans allow them to build up bigger root systems, meaning they can mine the subsoil for nutrients and minerals, and require less watering. Aside from rhubarb, asparagus and globe artichoke, however, we are largely unaware of the perennial vegetables potentially available to us. In this well-organised book, more than a hundred perennial vegetables are described, with plant histories, tasting notes, growth habits and preferences, hardiness ratings and potential pests.
Though primarily aimed at North American gardeners, most information is highly relevant to Europeans too. The Andes turn out to be a source of all sorts of interesting crops, such as oca, a relative of our native wood sorrel, whose tubers taste like potatoes with sour cream – essentially a perennial ready-meal; and canna, a plant already familiar to gardeners as an ornamental, but which also produces good crops of roots in damp marginal soils. It is, however, the improbable ‘air potato’ that stands out in this book for its pure vegetable insanity. Capable of growing to more than 50ft, air potato is a variety of yam that produces heavy crops of aerial tubers, which hang from the vine-like fruit. Obviously, this plant counts as incontrovertible proof of the existence of a benevolent creator-being.
Also included are plant lists for different climate types, nursery and seed company addresses, as well as sections on plant care, propagation, fencing, mulching and other techniques useful for the establishment of a perennial garden. If you are an adventurous gardener who wishes to grow more food for less work, this is the book to get you started.
Perennial Vegetables by Eric Toensmeier (Chelsea Green Publishing, £22.50)
This article first appeared in the Ecologist July 2008