Autumn is the best time to collect tree seeds and berries for propagation. Growing from seed can sometimes be a slow and erratic process but it is very rewarding in terms of the variety of seedlings produced. Rowan, alder, hazel, elder, shrub roses, hawthorn, guelder rose, blackthorn and most native trees can be grown in this way.
Collecting the seed
Seed should be collected as soon as it is ripe and sown immediately. Seeds which are contained within fleshy fruits such as rosehips, elderberries should be squeezed out of their soft casings before sowing. The seeds of many of these berry bearing shrubs and trees will only germinate in the wild when they have been eaten, digested and deposited by birds and mammals.
Many seeds have a hard outer coating which will prevent germination unless it is broken down by any one of the methods known generally as stratification. The simplest way if doing this is to expose the seeds to a period of intense cold which will break down the protective layer. Any seeds which prove difficult to germinate should be sown and the pots left outside for the winter in a position which is exposed to the action of ice and frost. Alternatively the outer coating of large seeds can be damaged by making a little cut in each seed with a sharp penknife. For smaller seeds, rub them between two sheets of sandpaper.
Sowing the seed
Individual seeds should be put into 15 cm (6”) pots of proprietary seed compost or sandy soil, so they lie 2.5 cm (1”) beneath the surface of the compost. Stand the pots in an old frame or cool greenhouse until the following spring. Most species will germinate in this way, but any that prove difficult should be exposed to frost. As soon as the seeds show signs of growth in the spring, move the pots out into a partially shaded area. (The seedlings need plenty of light but should not be exposed to direct sunlight). Keep the compost moist and grow on, transplanting to bigger pots as necessary. Young trees should be planted out into their permanent positions in autumn, two years after sowing.
Note: Some trees take several years to germinate successfully (particularly if there is not a sufficiently cold snap in winter). Keep the pots outdoors for two or three seasons before discarding them.
Collecting seeds from nuts, hips and berries
Alder (Alnus glutinosa)
Hard green clusters. Collect before they turn brown and woody.
Blackthorn (Prunus spinosa)
Blue-black, downy fruit. Squeeze flesh to remove seed.
Elder (Sambucus nigra)
Black berries. Squeeze to remove seed.
Guelder rose (Viburnum opuius)
Bright red berries. Squeeze to remove seed.
Hawthorn (Crataegus monogyna)
Dull red berries. Each berry contains only one seed.
Hazel (Corylus avellans)
Hard cobnuts. They are ripe for collecting then they change from green to brown.
Rowan (Sorbus aucuparia)
Red berries. Squeeze fruit to remove seed.
Shrub roses (Rosa species) Red hips. Mash to pulp and leave to dry before extracting seed.
Note: Taking hard or softwood cuttings is certainly the easiest and most reliable way to increase your stock but the resulting plants will be identical to the parents. In the wild, trees and shrubs spring up naturally from seed and contain a great deal of interesting genetic variation. It is worth having a go at collecting seed just to see what turns up.
Reproduced with permission of North West Parks Friends Forum