The blooms begin in mid summer (July) and continue well into fall (whenever frost sets in) on plants 24 to 32 inches high. Give them some support to help hold up the huge, heavy blooms; you don't want to miss a minute of the show they put on!
Dahlia is a sun-lover, happiest in rich, well-drained, moist soil. It is hardy only through zone 8 in the north, so you may want to dig it up at season's end and store it indoors to replant in spring. It forms a tuber, and is easy to tuck away in a shoebox filled with clean kitty litter or vermiculite.
In the vase, 'Summer Night' lasts more than a week, stealing the thunder of all neighboring blooms and inspiring many compliments. Of course, it does exactly the same thing in the garden, so you have a tough choice to make!
Like most Dahlias, 'Summer Night' needs full sun and benefits from very fertile soil--we recommend a nitrogen-rich liquid fertilizer once a week throughout June. Keep 'Summer Night' well-fed and watered, give it plenty of sun, and it will reward you with an abundance of late-season color! Zones 8 to 10.