The Garden in September
Kari-Astri Davies is savouring the flushes of late-flowering plants as the garden moves gently into autumn “Hedge-crickets sing; and now with treble soft The red-breast whistles from a garden-croft; And gathering swallows twitter in the skies”
John Keats, ‘Ode to Autumn’
Overhead, chittering clans of swallows are gathering, swirling high over the garden to feed before embarking on the long journey south. Their migration marks the end of summer and the beginning of autumn. On my garden walk now, I am drawn to the south- facing garden with its raised beds. The cooling nights favour some of the tender plants, which get a second wind. Nasturtiums recovered from caterpillar season festoon the abutilons and buddlejas. Fuchsias put on more flowers, and begonias heave a sigh of relief before finally going back into the conservatory for the winter. Tropical-looking B. luxurians is huge, more than 6½ft (2m) tall, so needs to be cut back a bit for overwintering. The kneed stems root happily in water.
A second try
In the main border, sunflower Helianthus debilis ‘Vanilla Ice’ adds upright dabs; solidity among the late summer plant jumble. I haven’t grown it for a couple of years, so it has made a welcome return to pep up the planting, taking over from the finally flagging white cosmos ‘Purity’. I did say a couple of years ago I would not choose this cosmos again, as it grew too big. But frankly, the lower-growing ‘Sonata’ was such a washout last year, the more exuberant ‘Purity’ has returned, but located with more consideration for its eventual girth and height. Opposite, in the tawny border, Red Admiral butterflies take advantage of the fairly nondescript but late-flowering buddleja ‘Beijing’. The threat to take one of the two buddlejas out of this border to create space for more interesting plants has yet to be carried through.
The time for dahlias
I’m a little stuck. Four years ago, I wrote about Dahlia imperialis, a single pink-flowered giant which grows to just under 30ft (9m) in its native Mexico and Guatemala. It is summered in the ground and in pots, and each year, the tuber gets bigger. It is now so heavy we have to use a sack truck to haul the pot about. Digging a hole for the tuber is becoming a major excavation, so this summer it stayed in a large pot. The substantial stems can take up to 2 gallons of water a day. Although very late into flower anyway, so far, not one bud has ever been attempted. In late autumn, the stems are cut down and the tubers left in the pot, packed out with bubble wrap, in an unheated wooden workshop. It has survived the last three winters like that. How long do I carry on working with this ungrateful monster? D. campanulata is another biggie from Mexico, known as the weeping tree dahlia.
Both dahlias can be bought as rooted cuttings from the UK’s National Dahlia Collection. At least last year D. campanulata produced buds, although they didn’t quite get to open before the frosts. I dug up the tubers and stored them in the unheated workshop as well; one survived the winter despite the tough love. I am checking daily now for forming buds.
Cutting and sowing
Last year in early September, I tried taking stem tip cuttings of selected dahlias: it didn’t work. An internet source suggested dahlias were sensitive to day length, and to root cuttings successfully at this time of year needed artificial light. I’ve found that D. imperialis cuttings tend to sit all winter in the conservatory, in a covered propagator with no extra heat, mostly not rotting, but not rooting visibly until spring. I am also going to be sowing seed as it ripens. Digitalis in the tawny bed, including D. ferruginea, are generally short-lived and need augmenting. Most umbellifers enjoy a winter freeze. Seed should ideally be sown fresh.
“Crown’d with the sickle, and the wheaten sheaf, While Autumn, nodding o’er the yellow plain, Comes jovial on” James Thomson, ‘Autumn’