24″ to 30″ When I think of a summer garden the first plant that comes to mind is the Dahlia. They are the epitome of summer and a must have for the garden. The ‘Mystic’ series features very dark foliage, often nearly black. This selection, Mystic Dreamer, features large, single violet colored flowers with lighter edges.
One of the biggest problems we have with Dahlia’s here is mildew. I have had good success with horticultural oil (the highly refined type). Spray with a low concentration, 1/2 strength mix, weekly or as often as you can. Once mildew starts it is hard to stop so these oil sprays add a protective layer to keep mildew away.
Another method is to use a product called Actinovate. This is a natural bacteria that attacks the mildew fungus. Very safe and very effective, but also needs frequent use. We apply weekly at the nursery.
Dahlias grow from tubers, somewhat like potatoes.