Dahlias flower from the middle of summer to the first frost in autumn. They can be grown in various soil types, as long as they are fertile and well drained. Dahlias make an excellent border plant as well as being ideal plant for a splash of summer color in containers.
Dahlias are classified into ten groups according to their flower type: single-flowered, anemone-flowered, collerette, waterlily, decorative, ball, pompon, cactus, semi-cactus and miscellaneous.
Mid autumn is time to lift the tubers, as soon as the foliage has been blackened by frost. Clean of soil, cut back stems to about 15 cm and stand upside down for about 3 weeks in a frost-free place to drain water from them, trim off any fine roots and treat the tubers with fungicide.
Pack them in wooden boxes, in vermiculite, coir or similar medium. Store in a dry, cool, frost-proof place and inspect them regularly over the winter. If any mildew or rot has developed, cut it out with a clean, sharp knife and dust the cut surfaces with sulphur.
