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I am changing my mid-October priorities. They used to be cutting back flower borders, taking half-hardy flowers under cover and having one last blitz on weeds while they were still green and visible. October 13 was the marker in Britain: frost would probably come soon after and it was no use expecting marginally hardy salvias to survive it. Mid-October was the time for a big to and fro: new planting was never in my mind until the turnaround was finished.
Of the two main seasons for planting borders, spring used to seem preferable to autumn. In spring optimism runs high, whereas autumn used to seem the end of the road. There was a further canny advantage. If the winter was harsh it might kill autumn-planted newcomers; better to leave them unbought until spring so that they could die with their suppliers rather than in our gardens.
Recent autumns have changed the ground rules. Frosts have been delayed into November and in mild, wet weather plants continue to increase their roots. New planting, dividing and moving can attach to this pattern, allowing plants to make a month’s progress before the winter begins. They are then better rooted and more able to survive what a dry spring inflicts on them. In the new mid-Octobers, moving and splitting are often best done together with buying and planting new stock. I will give some basic advice on them and then on sowing, a neglected trick with which, ever hopeful, I will conclude.
Moving plants around used to be recommended only when they were dormant in winter. Obviously, plants still in full flower must be left alone: some of them, like the lovely white Japanese anemones, resent being moved anyway. The best ones to move now are those that flowered before August: day lilies, hardy geraniums and non-repeating phloxes to the fore. Cut off most of their top growth and water them for a few days before moving them. By the end of November, if recent autumns are a guide, they will already be settled in.
Day lilies are great splitters © GAP Photos/Bozena Piotrowska
If you want to split your plants, you can usually do so without uprooting them. Position a sharp spade near the outer half of an established plant and then drive it swiftly through the roots, repeating the strike in a circle until you have loosened an entire portion. Then dig it fully out, roots and all, splitting it again if you so wish before taking the bits to new positions. Day lilies are great splitters, improved by the process, as are many heleniums and monardas. It is fun and it gives you plants for free.
Buying in new plants is also timely. Next year they will be even more expensive and in spring there is more of a chance of buying a plant in a litre pot which has hardly yet rooted into it. In autumn smaller plants are well rooted in 9cm pots and are quite sufficient, having a month or so to enlarge before next year.
It may still pay to buy a big individual plant in a pot up to 3 litres if it has a mat of roots you can divide into several more as soon as you tip it out. Division is an extremely easy operation but there are a few tricks which help it to succeed. Soak the entire root ball in a bucket of water and then tip it out of the pot, and tease it into several separate pieces, pulling the roots apart from the bottom upwards, not the neck downwards. If the root ball is too solid to split by hand, stand it upright on a hard surface, a paving stone being just right. Then position the sharp blade of a spade just to one side of the plant’s central root and drive it as rapidly as possible through the root ball with one firm stamp of your foot on the spade. You will then have two pieces for the price of one. You can usually subdivide them into another three or four.
Caryopteris flowers profusely in autumn © GAP Photos/Marcus Harpur
Syringa Princess Sturdza © GAP Photos/Bozena Piotrowska
Two mistakes are to plant new perennials too closely and not to improve the soil before planting into it. The traditional spacing for border plants was three or five to a square metre, but millennials’ impatience has doubled the density: revert to the old spacing, remembering that you are planting for growth, not instant exterior decoration.
I made two new border plantings earlier this year, vivid illustrations of why time and money spent on the soil are never wasted. One was in newly laid topsoil to a high specification, the underlay for a new Oxford college quadrangle. Even after the drought it is amazing how asters, sedums, campanulas and dark blue caryopteris, the shrub that flowers flat out in autumn, have grown after only one year. The soil was pretested for its balance of trace elements and enriched with fertilisers where necessary.
Princess Greta Sturdza considered heavy soil prepping to be the key to her garden’s vigour. When I told her my new delphiniums were struggling, she tapped me with her stick and told me to ‘prepare or despair’
The second planting was at home in a bed that had begun to look tired. Some of the same varieties of plant went into it, but as the surrounding bed was already planted, preparation was limited and, like most of you, I was in a hurry. Half a bag of rotted SylvaGrow manure was as much as I dug in. The results contrast tellingly with those in Oxford: about a quarter as much growth and flower.
If a border is already planted it is too late to do enough to prepare it. Years ago I rushed in, keen to make a new garden. I was then rebuked by a great gardener, Princess Greta Sturdza, in the fine garden she made at Vastérival in Normandy. In older age she tended to be despotic to visitors and greet them with an admonitory wave of the shepherd’s crook she liked to carry. When I told her my new delphiniums were struggling, she tapped me with the stick and told me “prepare or despair”. She considered heavy prepping before planting to be the key to her garden’s vigour. I grow Syringa Princess Sturdza, a fine pink-flowered lilac, and recall her command whenever I pass it.
Spring early flowerers include Papaver Beauty of Livermere . . . © GAP Photos/Jason Ingram
. . . and Lychnis chalcedonica © GAP Photos/Pernilla Bergdahl
After as much prepping as space allows, I will buy in some of next summer’s early flowerers to establish them in the next five weeks. The fine crimson poppy, Papaver Beauty of Livermere, will be one, and vivid scarlet- flowered Lychnis chalcedonica another, a bright plant to dot individually round a smaller garden. Possibilities abound but I will also take time to sow annual seeds.
Recommended
Hardy annuals, sown in autumn, are a gamble most gardeners overlook. This year they worked and I had blue cornflowers, love-in-a-mist, red poppies and blue anchusas in late May and June far brighter than the wallflowers which had hated the wet winter. Sow them directly into lightly raked ground or better, into boxes and then move the seedlings on into bigger boxes so that they are spaced about 7 or 8 centimetres apart. They can then be transferred into gaps in the garden in March. I love seeing blue cornflowers, sown now, flowering in May, a twist to late spring bedding. They must be hardy annuals, not half-hardy petunias or marigolds. Some years they flourish, some years they fail after too much frost. If gardening was predictable it would not be such fun.
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