Where can I get a cutting or seeds of Oxalis regnellii ‘Atropurpurea’? I saw it at my niece’s house in the US and have had no luck finding it here.

Mrs R. Rhys, New Barnet

I suspect that you can’t find it because you’re looking in the wrong place. It’s a perennial, with funny little tuberous roots, but it’s not very hardy and usually it’s to be found in the houseplants section of garden centres. In a sheltered spot it may survive outdoors, but more often it’s a glamorous conservatory plant or an outdoor bedding plant. Good with scrambly pink verbenas. But the botanists have changed its name to Oxalis triangularis subspecies papilionacea ‘Atropurpurea’. Triangularis because of the leaf shape: it’s like a taller clover but each segment is clearly triangular. Atropurpurea because the leaves are black-purple with pink flowers. There are plenty of online stockists.

I have an old Rosa glauca growing up the side of an arbour. It has only two thick main stems and one thinner one, no foliage at all on the lower metre but plenty higher up. How do I get some lower foliage without losing the height?

Mrs C. Abbott, Oxford

Maybe you should settle for losing the height? The beauty of this rose is in those plummy, blue-grey young shoots and pink flowers close-to, and if you let it get big and woody you lose the best of that. I’d chop the whole thing down next winter and prune itregularly after that. It self-seeds in many gardens and the plants you see for sale are always seed-raised, so they can look a bit wimpy when you see them for sale in pots; but don’t be put off, the younger they go in the better.

stephen.anderton@thetimes.co.uk

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