AUTUMN PROPAGATION

AUTUMN PROPAGATION

September and October are great months for propagating all sorts of plants. They have had their summer growing period and now stems are beginning to harden up ahead of the winter, but there is still enough warmth left to keep parts of the plant active. Roots can continue to develop at this time of year. Many flowering and fruiting shrubs can be propagated by hardwood cuttings taken immediately before and just after leaf fall. Herbaceous plants can be divided and replanted in autumn and many annuals are ready for harvesting seed pods to save our own seed for sowing next spring. Now is also the time to take cuttings of geraniums and impatiens from the best varieties to root at home and over winter on a windowsill or in the greenhouse if it has some heat.

Hardwood cuttings

This is a very busy time for nurseries that produce a lot of their shrubs from hardwood cuttings.

Cornus, senecio, cistus, lavender, rosemary, forsythia, philadelphus euonymus, viburnums and hundreds of others will all root from a cutting about four to six inches long, removing the lower leaves and making a cut under a leaf node or with some such as pyracantha pulling off the shoot with a heel. These are then lined out in trays or in a cold frame bedded in a propagation medium (mixture of half compost and half sharp sand or grit.) Keep the compost moist and the frame well ventilated in sunny weather. Plants should be well rooted and put on some growth by next summer when they can be carefully removed and either potted up or planted out.

Blackcurrants and gooseberries can also be done this way, though they do not need the protection of a cold frame.

Divide herbaceous plants

Flag iris, oriental poppies, heleniums, Shasta daisies and many others can be lifted, divided and replanted. Add compost and some fertiliser at this stage. Heucheras can be propagated by pulling off sideshoots and using them as cuttings in a cold frame or greenhouse. They will root in a couple of months.

Collect seeds

Poppy ladybird, Himalayan blue poppies, other poppies and annuals that produce viable seed pods can be harvested for their seeds. Dry off the pods and extract the seed storing them dry but cool.

Summer flowers

Geraniums and Impatiens can be propagated by cuttings taken now. Geranium cuttings of about three inches long snapped off the plant and potted up will root after a few months and can be over wintered on a sunny windowsill. Keep them frost free and cool, but if you wish to produce more plants grow them warmer and feed them. As soon as they are big enough take out the tops and use these as extra cuttings.
Impatiens are even easier as cuttings three inches long with all lower leaves removed are dropped into a jar of water. They will root in about six weeks and can then be potted up.

Both these plants are suitable as flowering house plants in early winter then again in spring.

Plant of the week

Gladioli have been at their best for several weeks. They can really add colour, impact and height to flower borders and it is possible to pick up bags of really good corms very cheaply.

The corms are lifted and dried off to store over winter in a cool dry place free from mice and each year you can add a few more corms of different varieties.

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