Clematis, sometimes referred to as the Queen of Vines, offer astonishing color in the landscape. There are over 300 remarkable species. Flowers can be single, multi-petal or bell-shaped. And range in color from red, pink, purple, lavender, blue, white, yellow and multi-color. Most gardeners are familiar with Clematis grown as vines but there are also bush varieties (pictured right, ‘New Love’ with Black-Eyed Susan). Clematis bloom best in sun to part sun and range in hardiness from Zones 3 – 8.
All Clematis enjoy nutrient-rich soil. When planting, dig a hole twice as wide and deep as the pot (not a typo). Mix organic matter (i.e., compost) into the soil that is removed. Backfill the hole halfway with the amended soil and set the clematis root ball on the mound so the crown (point where stems meet the roots) is a few inches BELOW the soil level. If growing a vine Clematis, tip the plant (up to a 45 degree angle) in the direction of its support and then backfill with the remaining soil. Water in well. Once a year, in spring, fertilize with a granular organic fertilizer like Espoma Plant-Tone.
Now to the real reason for this article – how to prune Clematis. Clematis are grouped into three groups based on pruning requirements: Group 1, 2 or 3.
Group 1: These are the earliest to bloom in spring. They only set flower buds on old wood (the previous year’s stems). Pruning should be done immediately after the vine has finished blooming. (Pictured C. ‘Blue Bird’)
Group 2: These usually start blooming in late spring. They bloom on both old and new wood (current year’s growth). These should be pruned lightly in late winter or early spring when green leaf buds begin to swell on stems. Prune just above swelling buds – either those higher or lower on stems depending on the height desired. A second pruning can be done just after the flowers finish, before a second round of flowers later that summer. This group has the largest flowers, some reaching 5” – 8” across.(Pictured ‘Rebecca’)
Group 3: These usually start blooming in early summer, some even later in the season and only set flower buds on new wood. In late winter or early spring, stems can be pruned hard to within a foot of the ground. Patio Clematis (compact varieties that usually grow between 3’ – 6’) are in this group, as is Sweet Autumn Clematis (invasive in some states) and Clematis virginiana (a native, non-invasive alternative to Sweet Autumn Clematis). (Pictured ‘Princess Diana’)
To learn more about growing and pruning Clematis, visit Brushwood Nursery’s website, a top-rated mail-order company specializing in Clematis. The owner, Dan Long, is a friend and a highly respected grower in the horticultural industry.