September has such a wonderful
mellow quality about it – all the summer fandango is fading but the weather is often still very pleasant for gardening, so here are some tasks to have a go at, including cutting back spent plants, giving the hedges a final trim, and taking some herb cuttings:
If you want a good show of general loveliness in September, you need to think about what to cut back.
There will probably be a lot of plants in your garden that have done their thing beautifully through the summer but are now ‘past it’ (I recognise the feeling after a hard day among the borders), so what do you do? Leave the stems and seedheads on because you want the birds to have shelter and sustenance during the winter? Or because you’re too busy at the moment to do it? Or because you’re bone idle (‘How very dare you!’)? Well, you certainly can put off the whole cutting-back thing until early spring, but if you don’t cut ANYTHING back, there are some dangers:
- You’ll be leaving all the plants that die back in an ugly way – Aconitum, Leucanthemum, lupins, etc. along with all the pretty or architectural ones – Phlomis russelliana, Ajuga, Helenium, Cardoon etc.
- You’ll be faced with a lot more work in February/March.
- Heavy rain can make tired lank stems look an awful mess.
- You’ll be giving slugs and snails lots and lots of cover among soggy rotting foliage.
- You may well be missing out on some September lovelies that are being leaned on or obscured by the heaps of old stalks belonging to its summer-flowering neighbour.
- Things like Aster, Hesperantha (Schizostylis), Liriope, Ceratostigma or Hyelotelephium (Sedum) etc. will shine out so much more in the softer autumnal light if they are given more of the stage, like the lovely Sedum in the feature picture above.
So be judicious, look critically at your borders right now, and decide which plants to cut back and which to leave until the new year. Maximise your chances of prolonging the colour and interest in your garden.
Early autumn is the perfect time to divide many perennial plants to rejuvenate them or make new plants, and I find it a particularly good time to divide ground-cover plants like Lamium, Alchemilla, Pulmonaria, Lysimachia, Geranium etc. so that they cover more ground.
It’s terribly easy to do, I promise, and the great thing about doing it now is that the soil is still warm, and the roots will have plenty of time to become established before winter frost halts them in their tracks.
Chop through the roots at the edges of the clump and hoik them out. You’ll mostly find that these bits will naturally divide into smaller pieces with some roots and leaves attached to each piece, so pull the bits apart or cut through them. Then plant the pieces into good loosened soil where you want them, and at the same level they were before. Firm the pieces in and water them well.
Super job! And so much better than leaving bare soil that is such a magnet for weed-seeds over the winter.
HONING THE HEDGES
Hedges will all be slowing up now before they stop growing altogether for the year, so a trim in September should keep them looking neat and controlled all the way through to spring.
Our beech hedge will be getting this treatment, and beech has the added advantage of being deciduous but keeping its nut-brown old leaves on all winter (added protection value) before the luscious red shoots herald the new foliage in spring. Quick growers like Lonicera nitida and Ligustrum (privet) should get their final cut of the year round about now, and evergreen hedges like yew can also be trimmed and neatened, though I know that some people prefer to tidy up their evergreen hedges in midsummer, to avoid the danger of creating bare patches.
Canes, string and even a spirit level can all help to keep the top line straight, and if you can manage a slight slope inwards on both sides creating a ‘batter’, so much the better – if the hedge is a little bit thinner at the top than the bottom, more sunlight will reach the lower branches to keep it bushy there, and the hedge is less likely to split if it becomes loaded with heavy snow.
One hedge of ours that won’t be having an autumn cut is a long run of Rosa rugosa because we want to enjoy its huge red hips and lovely yellow autumn colour. We will leave this one until next March when we don’t tinker about just taking off weak shoots but chop the whole lot down by half – a prickly job but very effective!
• Take some cuttings of herbs – marjoram, sage, lavender, rosemary etc. Little non-flowering shoots tucked round the edge of pots of gritty compost, watered, and kept under glass in a warm spot will root pretty easily.
• Chard will be starting to slow up its production of leaves as the weather gets colder, but if you pot up a root or two of this veg. and bring them into an unheated greenhouse, they will go on throwing out leaves for you all through the winter.
• Re-seed bare patches in the lawn – the grass germination will be lovely and quick in the warm soil.