Sunday, 11 October 2009

attracting caterpillars to Brussels sprouts

Brussels sprouts are overwintering members of the brassica (cabbage) family.

They like good fertile soil and firm ground.

They will grow on through the autumn and then produce their 'sprouts' (compact tiny cabbages with a spicy flavour) around time for Christmas dinner.

Our mistake in the past has been to plant the young plants into insufficiently firm ground. The result has been leggy plants with loose, open 'sprouts' that feed the caterpillars of large white butterflies in the summer and hens in the winter!

So, this year, I decided to make some changes. I gave the earth a good stamping before planting. And
I also broadcast trefoil seed beneath the little transplants.

The trefoil does three things:

  1. as a legume, it will increase the soil's fertility and this will benefit the Brussels plants
  2. it is also claimed that an understory of green foliage reduces the contrast between the normally brown earth and green leaves of the Brussels plants, reducing the ability of pests to find the Brussels with consequent reduced damage by insects.
  3. trefoil is the larval food plant of the common blue butterfly. By using trefoil, we may have persuaded a common blue butterfly passing earlier in the season to lay some eggs.
I know that it may seem perverse to complain about the caterpillars of one butterfly species whilst actively trying to attract the caterpillars of another species to come and feast. But my mission is to make my plot as productive for me as possible whilst making it as attractive to wildlife as I can. Common Blues will not harm my Brussels and I might just play a small part in helping one of our prettiest little insects.

Whatever happens I hope that my Brussels will benefit!

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