Gardening Articles: Flowers :: Perennials
by Charlie Nardozzi
The stalwart of many perennial borders and quintessentially 'English', delphiniums have broadened their range, both in size and heat tolerance -- good news for gardeners with small gardens or in warm climates.
Best known are the majestic so-called English types, which are blooming now in many areas. These densely clustered blue, pink, purple, red, or white spikes, growing to 6 feet tall, seem to dance along the backs of perennial borders, and they make great cut flowers. There are also versatile dwarf types, bushy plants with shorter spikes of vivid blue, and white flowers that blend well with low-growing perennials in the front of the border. A third type is midsize between these two. Even though there are more than 300 kinds of delphiniums, this article focuses mostly on the tall hybrids developed from D. elatum, and the shorter hybrids of D. belladonna and D. grandiflorum.
In relatively cool and moist summer climates, as in the Pacific Northwest and Northeast, delphiniums flourish, often growing into large clumps that live up to 10 years and can be periodically divided. However, delphiniums don't thrive in the hot-summer areas of the South and West, where they are grown as annuals, if grown at all. By selecting dwarf varieties and trying new, more heat-tolerant tall varieties from New Zealand, even gardeners in warm-summer areas can now grow delphiniums that prosper.