– The hairy oriental poppies have finished. Pull off the tops and fill the space with some annual planting. Try them splurging out of hedge bottoms where they’ll leave no gap.

– Time to clip topiary shapes in box, yew and phillyrea. Bay is better shaped by nipping out the tips, unless it is impractically large. Leave beech and hornbeam until they have made their second growth spurt of the season. Young leylandii are best clipped regularly all season to make them bushy; older specimens slow down and can be clipped just twice a year, now and in autumn.

– To prevent self-seeding, remove the seed heads of aquilegias, alchemilla, alliums, polemonium and chives.

– Keep sweet peas thoroughly picked to ensure further flower production.

READERS' QUERIES

We wish to plant a narrow, fast-growing evergreen hedge to cover our 6ft fence. Would an appropriately pruned Portugal laurel fit the bill? C. Pritchard, Epsom, Surrey

I wouldn’t use Portugal laurel (Prunus lusitanica). Yes, it’s far more stylish and attractive than the common, large-leaved cherry laurel, but it also wants to be big. You might keep it down to 6ft, but it wouldn’t stay elegantly narrow.

Why not think about ivy? It would be up there in 2-3 years, after which you would just need to clip it or tidy it up with secateurs. Grow it on a wooden trellis on stout posts a foot from the fence and it will be there for 15 years. Grow it on concrete posts and steel reinforcing mesh and it will be there longer than you. There are so many kinds of ivy, too: smooth, pointed or curly leaved; leaves splashed with yellow, cream or white; glossy, dull or marbled; leaves the size of your hand or the size of your thumbnail…

Of course, if your idea of heaven is painting fences, then ivy is not for you, but any hedge is going to make a fence inaccessible.

I have just returned from Israel, where the sumptuous purple-blue flowers of the jacaranda trees are overwhelmingly beautiful. I’d like to grow a seedling from the rock-hard seed pods I have brought back. Although I’ve been successful in the past by soaking them in hot water and then germinating them in the airing cupboard, can you suggest when I should do this – now or next spring? Mr P. Balen, Radlett, Herts

Who could resist having a go! If this were a tree that might just live outside, like certain acacias, I would say sow as early as possible in spring. That way, it could be planted out with most of the season still ahead of it in which to settle down and be better equipped to handle our winter. It would also mean the root did not have to spend a winter in a pot. But if the tree is to live all its life in a pot – and jacarandas stand no frost – then everything is different.

I’d sow any time during the growing season and just pot it on regularly; not too much nourishment, mind you, or it will raise the roof. Don’t sow in winter, when the UK light levels are so low, especially indoors. Through the summer, it could live outside in a warm spot. Even without flowers, that ferny foliage is a delight.

stephen.anderton@thetimes.co.uk

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