GARDEN GURU

Q What has eaten the leaves of my purple sprouting broccoli and perpetual cabbage? They have so many holes in them that they almost look like pieces of lace.

Robert McCracken

A Several creatures like the leaves of cabbages and other brassica plants. Pigeons will strip away the foliage, while slugs will eat holes in leaves. I suspect yours have been eaten by caterpillars – I spotted some droppings in the photos you emailed. To prevent damage in the future, cover the developing crop with insect-proof mesh.

Q My penstemons usually produce an abundance of flowers. This year they put on strong growth, but had just a few flowers. Can you suggest why? Peter Berriman

A Penstemons thrive in sun or partial shade and will flower with abandon when set in fairly poor, stony soil. They tend to produce lots of foliage at the expense of flowers when grown in rich soil. But since yours have done well in the past, it could be due to plants being fed during the growing season. In terms of maintenance, cut shoots back in April down to strong new growth near the crown.

Q I love astilbes but they never do well in my garden. Can you give me some tips? Sally Purnell

Astilbes, admired for their A feathery flowers, like moist soil (but not waterlogged) and go downhill quickly if the ground dries out. They will tolerate a sunnier position if you keep the soil conditions right.