By Max de la Haye

Dahlias are very easy to grow. They come in all sorts of varieties and colours, but not blue. The diameter of the blooms varies from a maximum of 2 inches for a pompom to 12 inches or more for a giant. The height of a plant can be anything from 2 - 7 feet depending on variety, except the bedding type, which is generally 12 inches high.
For best quality healthy dahlia plants, I prefer to purchase from UK specialists. Suppliers can be found in garden magazines and on the internet.
Dahlias are tolerant of most soil types, but as they are gross feeders, the ground should be dug over, to a full spades depth in January, adding well rotted manure or garden compost. April is the month when a general organic fertiliser such as blood, fish and bone can be raked in to a depth of 2-3 inches before planting at the beginning of May. The spacing of plants ideally is in beds 5 feet wide allowing 3 foot by 2 foot 6 inches between each plant and at least 4 feet between beds. Use a 2 foot cane to mark where each dahlia is to be planted.
In early April saved tubers from previous years can be started into growth in a greenhouse or frame using potting compost. When shoots appear they can be divided into pieces. each with a shoot, with a sharp knife.
The beginning of May is the ideal time to plant new plants and tubers alongside each marker cane, covering the tuber with 1 - 2 inches of soil. Most important, do not forget to place a variety label alongside the cane.
As the dahlias start growing, keep an eye out for slugs. The little black ones can cause a lot of damage to young shoots - treat with slug pellets if necessary. Dahlias are rather susceptable to aphid, and you may also need to spray them regularly to keep them in check.
At the end of May place 4 canes around each plant, and using twine, put 3 layers equally apart, around the 4 canes for support. Flower buds should start to appear towards the end on June.
It is advisable to remove 3 or 4 pairs of side shoots to improve the quality of bloom, and stem length. Always remove blooms past their best to encourage successive blooms to appear.
If the blooms are required for display they need to be cut in the morning or evening, and placed immediately into water before dressing and arranging. With care, dahlias should give colour in the garden, and blooms for the house, right up till November.
Lift tubers in December, and after trimming, place in peat filled boxes and over-winter in a frost proof store.