Troy Scott Smith advises what tasks can be achieved in the garden before the first frosts.
Devoid of the exuberance of summer, the bones of Sissinghurst slowly begin to reveal themselves. Vistas open up and the sharp lines of Harold Nicolson’s design are once more etched into the garden.
Autumn is the start of the gardening year and, if the weather allows, many of the enduring tasks of the season can be achieved now, before the first frosts and the worst of the winter weather arrive.
First, we go through the whole of the garden and carry out a quick clearance of the weeds in all the beds and borders, before moving onto cutting down and clearing away the season’s growth. When doing any work on the soil during this period, we try not to trample the earth, as constant foot traffic ruins the soil structure, especially if it’s heavy clay, as at Sissinghurst. Instead, we carefully place wooden planks into the border and stand on them as we work; in this way, our weight is spread more evenly, avoiding compaction.
By cutting down and removing the spent plant growth, we are depriving the soil of what would become, in a natural habitat, organic matter that, in turn, would feed the soil. Instead, applying a mulch is our opportunity to return goodness to the soil and, here, we use well-rotted garden compost placed in a layer on top of the soil, spreading about a barrow-load per two square yards.
The clearing of last season’s growth should be completed before any new shoots begin to emerge. Sometimes, the spent flowers, foliage and stems can simply be snapped off the stems of phlox, for example but for others, secateurs are essential. We always begin with the daylilies (Hemerocallis spp.) as they quickly turn to slimy mush after the first frosts. The last of the perennials to be cut down should be the grasses and this is only done when new growth is starting to push through.
You’ll get another opportunity to make planting changes in March, but, if the conditions are right, I prefer moving and planting in autumn. Many herbaceous plants can be divided and replanted in one operation and we tend to do it while we’re clearing the borders. At the same time, biennials are lifted from their nursery ground and planted in the borders for spring display, where they occupy the place of vacated late-season perennials, such as dahlias, that we remove and store over winter.
During the dormant period, many plants can succumb to frost or excessively wet soil. We give a bit of extra protection to borderline plants, such as Melianthus major, by tucking bracken around the base of the stems. We also ensure that sufficient cuttings have been taken from potentially vulnerable plants before the first frosts; if it turns out that they aren’t needed as replacements in the garden, they can be sold to visitors in the following spring.
Evergreens in pots can be especially vulnerable if their roots freeze, they might not make it through the winter. Those growing in large pots can usually cope during mild winters, but evergreens in small pots should be protected. We grow most of ours in plastic pots that can be lifted simply in and out of the terracotta display pots. Removal of the contents means that we can place a winter ‘jacket’ over the pot to protect it, too.
We aim to carry out all the winter tasks of pruning, tying, replanting, forking and mulching by the time the garden opens again in mid March. However, with unproductive weather and Christmas ‘getting in the way’, our winter work usually continues well into April. Even so, winter frosts don’t cause nearly as many problems as late-spring frosts, when plants are bursting with soft new growth.
This winter, don’t worry when the temperature takes a tumble just make the most of the good days, then go inside and warm up by the fire.