• Roots can be forced in winter for fresh out-of-season greens. • Perennials are probably more productive in marginal areas as they start assimilating solar energy from early spring. • Some perennial traditional wild crop relatives may have disease resistance
(e.g. perennial cabbages may be more resistant to clubroot). • If you have limited space, it makes more sense growing perennials as vegetables tend to be more expensive in spring.
There are of course also some disadvantages • The land is permanently occupied and only one harvest a year is usually possible. • Perennials are mostly productive in the springtime. • Perennial weeds may reduce yields, but with knowledge weeds can also be a resource. • Perennials don’t last forever and some will need replanting every few years to maintain yields. • Viruses can be a problem (as is the case with potatoes, garlic, shallots and rhubarb). • Improved varieties are generally not available (here we can all contribute; join the
Facebook group Plant Breeding for Permaculture). Imagine a world without ready access to supermarkets offering more or less any vegetable at any time of the year. Actually, it doesn’t take much imagination. Here in Norway, I can remember that only 25 years ago there were only a handful of vegetables available in supermarkets in winter and the way things are going (climate change, peak oil etc.), in another 20 years seasonal vegetables should once again dominate our consumption. People have in the meantime become more accepting of weird and wonderful vegetables. Therefore, we should be looking at how to diversify locally produced vegetables, so that we can maintain a wide variety of local produce. One group of vegetables that has so far been little exploited are the perennial mainly spring-cropping species. Ken Fern, Plants For A Future and forest gardeners such as Martin Crawford and the late Robert Hart, as well as Eric Toensmeier in the US have done much to show the wide range of plants that could be used. This is my small contribution. Stephen Barstow Malvik, January 2014
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