Here is an interesting one: propagation by root cuttings. My problem is that my Acanthus are well established and not only seed themselves but those seedlings are the devil to get out because the tap roots are so deep. But, for all that, no garden is complete without the architectural Acanthus. One way of propagating them is by root cuttings.
Lift the plant during its dormancy (now, in winter) and, choosing young vigorous roots the size of a pencil, cut them away close to the crown. Cut these into 5-10cm lengths, insert vertically into regular potting compost with the top just below the surface of the soil, water and place in a cool greenhouse. Then wait.
It is also time to think about bulbs. Dahlias come in a variety of shapes and colours so there is something to suit most tastes, from the showy and dishevelled look of the Giant Cactus group through to the precise perfection of the Miniature Balls or Pompons.
If they are going to be saved for another year, they will need to be lifted in the next few weeks, because they do not tolerate hard frost. A week after the frosts have blackened the foliage, cut the stems down to six inches above the ground. Make a cut of one spade's depth around each plant, 12 inches from the main stem. Holding the stems, gently ease the tubers from the soil with the spade. Discard any broken tubers, and place the rest upside down for a week, under some cover, to drain off the water in the hollow stems. Once drained, place them in shallow boxes, barely covering them with used potting compost, and store in a frost-free place.
Winter colour
Hippeastrum, a genus of tropical and subtropical bulbs, is related to (and often sold as) Amaryllis. They grow from large bulbs, with one or two flower stems rising 18 to 24 inches above the green, strap-like leaves. Each stem carries a large trumpet-shaped flower. Specially treated bulbs come to market now for planting to flower in time for Christmas. Plant in a 5-7 inch pot of John Innes No 2 compost, leaving half the bulb exposed. Give a little water until signs of growth appear at the top of the bulb. To get them going, place them somewhere warm - over a radiator or even in an airing cupboard (but don't forget about them as they can come from nowhere almost over night).
Lily-of-the-Valley is not generally thought of as a house plant but it can make a very pretty and beautifully scented one. Dig up and pot a clump, then bring it on in a cool greenhouse. When the flowers appear, bring them into the house. When the show is over you can return them to the garden.
Alternatively plant a dozen plump crowns in a six inch pot of compost made up of equal parts loam and leaf-mould with some sharp sand added to give good drainage. Stand the pot in a frost-free greenhouse until January then bring them inside. Frequent watering is necessary for rapid growth. It is an under-rated little plant, and not in fact lilies at all, but a genus of only one species - Convallaria.
Tulips for bedding should be planted in November. They like a sunny, well drained position so if your soil is heavy you will need to place a layer of coarse grit beneath them as well as work some into the soil. Plant at up to three times their own depth, but remember that more shallow planting makes for easier lifting. What they lack in scent they make up for with their bright colours and of course the variety available is fantastic.
Their history is also fantastic and Anna Pavord has written about this in her authoritative and readable book The Tulip.
Dr Holliday is a GP in Windsor
November's tasks
- Propagation of root cuttings.
- Propagate root cuttings of acanthus, phlox and verbascum.
- Lift and drain dahlia tubers.
- Plant hippeastrum for Christmas flowering.
- Lift and pot Lily-of-the-Valley for indoors.
- Plant tulips.
