HELEN YEMM THORNY PROBLEMS

This week: a guide to grasses for the confused, how to prune a rose hedge in winter, and the sweet smells of Twitter

I shall be abroad in February and early March (which I understand is the conventional time for rose-pruning). Can I cut back my three-year-old rose hedge now (a label tells me the roses are Rosa rugosa ‘Alba’) and if so, how should I go about it? I have not pruned them before, but merely snipped off shrivelled hips.

MICHAEL RESTON – VIA EMAIL

After three years, your naturally suckering rose hedge should have started thickening up well. These roses are known to be disease-free and as tough as old boots (which is part of their allure as an informal hedge) and I find that my own come to no harm if they are pruned in the dead of winter. I think that, weather permitting, you should go ahead.

Start by cutting out at ground level some or all of the oldest (thickest and darkest brown) stems, as well as any skinny little ones that were produced late in the season and probably have shrivelled tips. The shoots that remain can each be pruned by half, back to points just above leaf scars (from whence will come thicketrenewing, flowering shoots in due course). Clear up the debris and make a note to feed and mulch in March.

While on the subject…. some rugosas that are grafted on to wild rootstock occasionally throw up vigorous suckers from below the graft that are less thorny, with matt green leaves. Wrench these carefully from their root rather than prune.

There has been much, of late, to distract even the most focused gardener away from the tilling of the good earth, not the least being the plopping on to our doormats of all the

TIP OF THE WEEK

combed through to remove old thatchy stems and flower stalks.

With this group, only larger clumps can stand being cut right back, and all tend to resent disturbance (splitting and replanting) when dormant.

Of your “mixed bag”, only the miscanthus is a warm climate grass and as such is slightly more tender than the rest (other common examples in this group are panicum and pennisetum). All stems eventually die back in late winter, the oldies left

seed catalogues. So, sitting in our socks with our feet up is the closest many of us may get to the back door for weeks. In the absence of in-box inspiration, I have gravitated to the Telegraph Gardening Twitter feed (@TeleGardening), to seek snippets of inspiration to pass on to you.

What you will find on Twitter is a friendly and connected Telegraph Gardening community sharing thoughts, information and photos, including some lovely evening shots of Wisley from Matthew Pottage (@ Matthew_Pottage). It also included many reminders of the not-to-bemissed whiffs to be found in winter gardens. Toby Buckland (@ TobyBuckland) reminded us to seek out the golden lily-of-the-valleyscented flowers of mahonia, while standing do provide a little protection for a new crop of bright newbies that starts to nudge upwards in early spring.

This group of grasses should be cleanly cut back so the plants completely renew themselves each year and gradually expand. Take care with the timing of the cutback. If done late, it is hard not to damage the precious new growth. Generally speaking, warm climate grasses only need dividing (in May) if they outgrow their space and become too congested.

Alan Gardner (@autisticgardner) favours the delicate scent of Lonicera fragrantissima. Derry Watkins (@specialplants), and Alan

Gray (@ERustonOldVic) rave about Daphne bholua, and Christopher Howell (@christophhowell) points out that the Birmingham Botanical Gardens have a wealth of scented shrubs for visitors to enjoy.

The flowers of Oriental hybrid hellebores, closely followed by smart new leaves, will look even more splendid if you carefully snip away last year’s foliage. Apply a sprinkling of blood, fish and bone, then mulch with leafmould or compost.

WISLEY LAKE VIEW Certain grasses benefit from a cutback, but timing is key