In my garden:
From Park Seed, we read:
These flowers arise over a long, long season. Expect them to begin in mid- to late summer and to continue right through early autumn! Many Clematis are early-summer bloomers, so if you're adding Avant-Garde™ to your Clematis garden, you will extend the season of color beautifully.
Each flower measures about 2 inches wide, with a very showy form. The magenta outer petals curl back a bit at the tips and the lavender inner petals gleam with a satiny sheen. This bloom has been described as "a Dahlia sitting on top of a Rose," and it really is one-of-a-kind beautiful!
Avant-Garde™ comes by its beauty and good garden performance honestly. It is the work of Raymond J. Evison, master Clematarian whose books on Clematis are industry standards. Evison Clematis are always vigorous and reliable, and Avant-Garde™ adds Clematis Wilt protection to the list of merits. This is a fine Clematis for a beginning gardener, but seasoned garden vets will love it for its unique form and terrific bloom strength, too!
If you're new to growing Clematis, welcome to the Queen of the Climbers! These woody plants are ideal for covering fences, climbing trellises, blanketing any vertical or horizontal support, and sometimes even scrambling along the ground!
As a general rule (and Avant-Garde™ is no exception), they like their roots cool but their tops -- the above-ground growth -- warm. So mulch them in well at planting time and refresh the mulch regularly. Give them well-worked, enriched soil, for these are vines that will live for decades if well cared-for. Let them thread through open-habit trees and shrubs -- they make a fine companion to Roses, often blooming at the same time and helping hide the rather leggy look of many hybrid tea Roses. They do have specific pruning requirements, but this is the only care they require besides tying or training onto their support.
Avant-Garde™ reaches about 10 feet tall and 3 to 4 feet wide, a manageable size for the garden. We ship one-year-old plants in 2 1/2-inch pots. Pruning Group III. Zones 4-9.