At its simplest, a polyculture of (mainly perennial) edibles will have plants of different heights or structures that snuggle up against each other comfortably plus some supporting plants to attract insects, accumulate minerals, or fix nitrogen.
Some of my favourite supporting plants are herbs because they are multifunctional e.g. fennel, thyme or lemon balm. Peas and beans are edible and also fix nitrogen, so they feature regularly as well.
By giving examples of some of my favourite polycultures I don't want to give the impression that they are fixed or standardised, or that there are "right" and "wrong" combinations. I would far rather convey that I think one of the chief delights of polycultures is that they are open to improvisation and it is great to try things out to see if they work.
Here are a few suggestions:
• Jerusalem artichoke with mashua climbing up and wild marjoram or lemon balm at the base. (These could be reversed, i.e. yacon with mashua or Jerusalem artichoke and French bean, with either oca or herbs at the base.)
• Yacon with peas or French bean twining round it, oca at the base.
• Kale (e.g. Daubenton's kale, nine star perennial kale, walking stick kale) in the shade of currant bushes or raspberry canes.
• Wild strawberries with buckler leaf sorrel / three cornered leek / shallots as ground cover or along an edge.
Anni Kelsey is the author of Edible Perennial Gardening: How to Grow Successful Polycultures in Small Spaces, which is available from our Green Shopping site for a special price of £11.21. Also available as a pdf).
Anni's Blog http://annisveggies.wordpress.com
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