Planting Flower Bulbs – Methods of Increase


crocus seed in pod - planting flower bulbs

Methods of Increase

Many bulbs, corms and tubers can be raised easily from seed but in the case of hybrids the seedlings are liable to vary greatly from the parent plants and you may have to wait a long time for flowering-size plants. Many amateur gardeners are likely to prefer the quicker vegetative means of increase.


Increase from Seeds

After the flowers of hardy cyclamen have faded, the seed pods can be found on coiled stems, and if these are sown as soon as ripe in a cold frame the plants which result will flower in three to four years. Lilies also can be raised from seed but some take as long as six years to reach flowering size. On the other hand L. regale, the Regal Lily, is one of those which can be brought to this stage in two years.

Pans or boxes can be used for seed sowing and it is always advisable to sow the seed as soon as it is ripe. Use the John Innes Seed Compost for preference, just covering the seeds with the soil mixture if they are very small and then with about 1/4 in. of sand. For larger seeds a covering of about 1/4 in. each of compost and sand will be satisfactory. Drainage should be especially good as the seeds will be in the pans or boxes for a long time. With some lilies, for instance, there may be no signs of life above soil level during the first year although all is proceeding well underground. Patience is more than a virtue where this form of propagation is concerned!

When the seedlings appear the pans or boxes should be moved to a cold frame and plunged if they are outdoors and then left alone for a considerable time – perhaps another two years – until they are large enough to pot singly or plant out in nursery beds. Watering and protection from pests will be the only attention required during this time. This first big move is made when the young seedling bulbs are dormant, and afterwards the plants are grown on to flowering size in the normal way.


Vegetative Increase

Some lilies, like Lilium tigrinum, produce small, round bulbs, known as bulbils, in the joints of the leaves and these can be removed after the plants have flowered and grown on like seeds. Increase by this means is a relatively quick way of getting flowering plants, perhaps two years from the time of sowing. Other lilies produce bulblets on the underground section of their stems and these, too, can be detached and grown on in a nursery bed for two or three years. Another method of propagating lilies is to lift the bulbs in early autumn and remove some of the scales. Insert these upright in a mixture of peat and sand in a seed box to about half their depth and cover with moist, sphagnum moss. Place them in a cold frame and wait for bulblets to form on the scales which can then be removed and potted or planted out in a nursery bed.

One of the simplest ways of increasing daffodils and other bulbs is to lift the bulbs when the foliage has died down and simply separate the clusters of bulbs. The smaller offsets soon increase in size if they are planted in good soil in nursery rows: To induce hyacinths to produce bulblets it is common practice to cut grooves in the flat, disc-shaped base of the dormant bulb so that bulblets will form along the edge of the cuts. These bulblets are then planted 2 in. deep in a sandy soil mixture and should produce flowers in their third year. Galanthus (snowdrops) are increased by offsets or division of the old clumps immediately the flowers fade. Tulips are propagated by separating the bulbs when these are lifted annually after the flowers fade.

Gladioli are reproduced normally by the cormlets (known as ‘spawn’) which form around the old corms or at the base of the new corms which form on top of them. The new corms are already of flowering size, and the cormlets can be grown on to produce flowering-size corms by the second year.

With tubers our action is determined by whether these are swollen roots or swollen stems. Dahlias, which do not form buds on the tubers themselves, must have a piece of the old stem bearing a bud attached, when they are divided. Tuberous begonias, on the other hand, do bear buds on the tubers which can then be divided with a sharp knife after growth has begun. Both these plants, of course, can be raised from stem cuttings as well, taken from stock plants started into growth in heat early in the year.

29. September 2010 by Dave Pinkney
Categories: Bulbous Plants, Plants & Trees | Tags: | Comments Off on Planting Flower Bulbs – Methods of Increase

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