Dahlias

Dahlias must be staked in order to bloom properly. Use a one-inch square wooden stake for the tall varieties and stout bamboo for smaller types. Insert the stake to a depth of twelve to fifteen inches before planting. The height should be about a foot less than the expected for the plant. When growth reaches nine inches, tie the main stem loosely to the stake. Use nylons, as this will not damage the stem and has a lot of give enabling the dahlia to grow without breakage. For plants with several main stems extra stakes will be required.

The planting distance between tall border varieties is three feet. The medium border variety two feet and the bedding variety about one foot. The tall varieties must have enough space to bush out therefore it is important that you leave the required space between each plant.
Plant dormant tubers in mid April but wait until early May in cold northern districts. Dig a hole about six inches deep with a spade and place the tuber in the hole and cover with fine soil. The crown of the tuber should be about three inches below the surface. Make sure the soil fills the spaces between the tubers. After filling press the soil firmly with your fingers.

Plant rooted cuttings in late May in southern districts but wait until early June in the north. Water pots about an hour before planting. Use a trowel to dig a hole which is larger than the soil ball for the cutting. Treat tubers bearing shoots as rooted cuttings.

The regular removal of faded blooms will prolong the flowering life of the plant. Water thoroughly during dry spells. Once the buds have appeared it will be necessary to water every few days if rain does not fall. Feed occasionally from July until early September. Use a liquid fertilizer.

The worst pests are aphids, capsids, red spider mites, caterpillars and earwigs which are easily controlled by using general-purpose systemic spray. In wet summers sprinkle Slug Pellets around young shoots. Diseases are rarely serious but two (mosaic and spotted wilt) are due to viruses and there is no cure. Remember to spray against aphids which are the virus carriers.