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Dazzling Dahlias.

Dazzling Dahlias.

Dazzling Dahlias
Dahlias flower from mid summer until the first frosts of autumn, providing bright colour in the garden for several months. All are frost tender and therefore need to be lifted and protected from the frost. They can be grown in most soil types, providing they are well drained and they prefer a sunny site.

Dahlia flowerheads have a diversity of petal forms in a wide range of colours, from white to rich yellow through pinks, reds and purples. Dahlias are classified according to the size and form of their flowerheads. Single, Water Lily, Ball, Pompom and Cactus are just a few of the types available.

Dahlias thrive in well-drained, fertile soil. They are greedy feeders so dig in plenty of farmyard manure or homemade compost and add bonemeal when planting. They can be planted as pot grown plants, as dormant tubers or as rooted cuttings from tubers. Remember these plants cannot be planted outside until all risk of frost is over.

Feeding
Four to six weeks after planting feed with a high nitrogen and potash fertilizer, either in granular form or by weekly applications of liquid fertilizer as a root or foliar feed. As flower buds develop, extra potash may be added to give good strong stems and strong flower colour. The tubers develop during late summer and early autumn so a feed of Sulphate of Potash is recommended but avoid contact with leaves and stems as this may cause scorch.

Pests and diseases

Dahlias are affected by Aphids, Earwigs, Red Spider Mites and Slugs.

Aphids - Leaves are often left sticky and the new growth will become limp. Aphids breed very quickly so they need to be controlled quickly. There are a variety of sprays available but try to use an organic one if possible and encourage ladybirds into the garden.

Earwigs - Young leaves and flowers are eaten and these pests can be controlled by placing inverted pots stuffed with straw, on canes among the plants. The earwigs use these daytime shelters from where they can be removed and destroyed. There is also an organic powder available.

Red Spider Mite - Leaves become dull on affected plants and leaves may fall prematurely. A fine silk webbing may also cover the plant. The cause is Red Spider mite and it is very difficult to control. A spray will have to be used but if the plant is very badly affected it will have to be lifted and burned.

Slugs - Slugs will rasp holes in the leaves and where are many ways to control them from placing containers filled with beer around the base of the plants to using salt or using slug pellets. You may use whatever method you prefer but there is one thing for sure, some type of control is necessary as these little pests will destroy your dahlias in one night.

Lifting and storing - When the foliage has been blackened by the first frost in autumn, trim back the stems to about 15cms (6ins). Carefully lift and clean the tubers of soil and leave to dry on old newspapers in a frost free area. After a few weeks, trim off any fine roots and treat the tubers with a fungicide. Place them upside down for a few more weeks to ensure there is no more moisture present. Label and pack them away in wooden boxes in vermiculate, coir or other similar medium and store in a dry, frost free area. Inspect regularly during the winter and if any rot or mildew is present cut it out with a clean sharp knife and dust with a fungicide.

If dahlias are stored correctly many plants can be kept for years providing months of dazzling colour throughout the summer and early autumn.