Helen Yemm's Monthly Tips
Gardener and writer Helen Yemm (weekly columnist for The Daily Telegraph) gives some helpful tips and advice on what to do in your garden each month.
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I always do a tour of the garden looking at it with fresh eyes as soon as I have finished juggling sprouts behind steamy windows and have stowed all the Christmas paraphernalia.
As their new flower buds are starting to emerge through the soil, it is a good time to cut down all the old leaves of Oriental Hybrid hellebores and mulch around their crowns with year-old, half-ready leafmould.
The flowers look much more spectacular powering upwards during the next few weeks if they are divested of all last years messy stuff. On mild days I have a bit of a tidy-up, open up cold frames and greenhouse doors, inspect the plants within and remove yellowing leaves.
As I write this we are having our first frosty spell of the winter in the South East. For those elsewhere who have escaped thus far, may I remind you to fleece up or move to shelter all those tender things in pots that might be harmed. The next few weeks are likely to be the really bleak, icy ones and – remembering last year’s minus 11 degrees – anything can happen with the weather, anywhere, with little warning.
Take comfort in the fact, however, that the days start to lengthen noticeably by the second half of the month. Meanwhile, if it is too horrid to garden, just enjoy doing a little forward planning: sit around in your socks leafing through seed catalogues.
Happy New Year.
It is (almost) not too late to:
Make sure you prune your early-summer flowering shrubs and (once-flowering) old shrub roses, cutting out old flowering shoots to reveal the new growth that will flower next year. Older bushes may need a major stem cut out from ground level to encourage the whole framework to renew itself. You can also give June-clipped box hedges that look a bit shaggy a neatening trim – in fact this is a good time to cut other evergreen hedges too.
Cut back and feed June/July-flowering perennials (even delphiniums) with a soluble fertilizer (wormery fluid, comfrey or sea weed, for example). Some perennials will come back and flower again this summer – but make sure you take the opportunity to renew slug defences. Alchemilla mollis and cat mint will come back from severe shearing, while borders generally benefit from the removal of excess, tired foliage, which can all be composted. Keep on deadheading all plants – except those plants that carry good-looking bird-friendly seed heads.
It is all systems go in the vegetable patch this month. Garden hygiene is important in order to minimize pests and diseases. But when clearing up and composting the debris of old crops, remember to leave the roots of legumes (peas and beans) in the soil for a few more weeks. This insures that they introduce all their nitrogen back into the soil – valuable fertiliser for next season’s leafy crops.
‘Relaxed’ gardening involves, I firmly believe, being one step ahead. It pays to nobble your first lily beetle before he finds a mate, to stake your delphiniums properly before that June thunderstorm, to take your favourite tender plants indoors - before they shiver and rot to death etc. etc..
So September is the month you should build a leaf cage – or even another leaf cage (read on) - in which to store and compost the leaves that are about to hail down on you – gardening manna from heaven.
All you need is four stout posts some chicken wire and something with which to tie them together. Leaves rot slowly by the action of bacteria and fungi and need neither to be covered nor to heat up, unlike ‘green’ garden waste. Make the cage bigger than you think you need, since initially leaves take up loads of space (unless you use a leaf-collector or mow them up, which shreds them, thereby speeding up the rotting process into the bargain). Don’t make the mistake of just piling up new ‘old’ leaves on top of last year’s almost-rotted ones, or you will get in a terrible pickle when you try to use them. And if you don’t have space for a leaf heap, or only have a few leaves anyway? Cram leaves into punctured black bags, shove them under evergreen shrubs and forget them for 18 months.
Gardeners get seriously itchy fingers by October, and want/need to start chucking out old annuals, cutting back really exhausted herbaceous plants and to carry out all sorts of adjustments – but with 40% less rain than normal last month (where I live, at any rate), the soil is still rock hard and we should all try to hold off disturbing plant roots until the soil moist. The great garden clear up is therefore going to be a protracted affair.
Given the right soil conditions, however, the next few weeks are a good time to lift and divide herbaceous perennials that need it (after three or four years). Their best bits – the outside sections – should be replanted in compost-improved soil, and will re-establish themselves quickly before the temperature takes a nose dive next month. It is now common practice not to cut back or disturb those plants that have ‘good winter structure’, or that provide birds with food - or just something to trapeze around on for fun. As long as this year’s debris is cleared away and everything is shipshape by March, all will be well.
This is not a serious shrub-pruning time, however much we may want to ‘tidy’ them up. Leave spring flowering shrubs such as Ceanothus and Hydrangeas well alone or you may find yourself cutting off the best flowering shoots. Late flowerers such as Buddleias and Hypericums can be cut back by half if they are a real eyesore, and pruned properly (down to a low, woody framework) at the correct time, in early spring.
Alarm bells should be ringing this month if you still have not planted your spring-flowering bulbs.
Tulips should definitely go in this month. Plant them a few inches apart in rough, slightly disorganized groups and bury them really deeply – 6 inches down if you can. This will put off all but the most energetic of squirrels, but if you have had a major problem in the past, bury a small piece of chicken wire between the bulbs and the soil surface. They really, really don’t like that.
I absolutely adore tulips. These are some combinations that work for me: ‘Ballerina’ tulips with emerging shoots of Euphorbia griffithii ‘Dixter’. ‘Spring Green’ tulips around the base of a white-barked Himalayan birch (Betula utilis ‘Jacquemontii). Tall, white-and-green-flowered Allium nigrum with ‘White Triumphator’ tulips.
Daffodil, crocus and allium bulbs do better the earlier they are planted – September or October are ideal times, I have to say – but better late than never and they can still go in now. Plant them all with at least twice their height’s worth of soil over their heads.
If bulbs are to be left alone to naturalize, sprinkle a little grit and slow-acting, long-lasting bonemeal under their bottoms at planting time for good measure. And remember to mark where you have planted them. I stick a few slim wooden kebab sticks in the ground around each ‘drift’ – quicker to do than write labels, and just visible enough for long enough to remind me not to plant anything else in what may seem, for the next few months, like a tantalizingly vacant spot. You may think you will remember where everything is, but how many times have we all stuck our spades through our bulbs, I wonder?
With masses of autumn leaves finally stowed away in chicken wire cages where, in around 18 months time they will have become useful humus-rich leafmould, thoughts turn at last to another important December job: Roses.
Although bush roses that need winter attention don’t get a look in until February, I generally aim to prune my climbing roses by Christmas. Mine are fairly young, so pruning is mainly a question of tying in some of the best new long growth (that I steered in the right direction while still sappy and pliable) to add to the permanent framework, and cutting back the shorter side shoots that bore flowers to within two or three ‘eyes’ – leaf scars – of their ‘mother’ branches. Next spring, the dormant eyes will sprout and eventually become shoots that will in turn bear flowers on their tips. Mature climbing roses need slightly more radical surgery: Some of the older, browner parts of the basic framework should be cut out each year, to encourage the rose to make some new framework growth that will flower with more ‘oomph’ than the old.
Ramblers, identifiable by their single, showy flush of flowers in July and massive unruly growth thereafter, are a different kettle of fish. In restricted spaces, some of the excessive growth may now need to be cut away completely. But care must be taken to save some of the long new shoots and tie them down, since they will carry the best of next year’s flowers. If ramblers are cut back and disciplined (by the ‘neat and tidy’ brigade…) as if they are climbers, flowering next summer may be a bit pathetic.