Clematis, often referred to as the “queen of the climbers,” have been soaring in Long Island gardens for generations. These plants offer gardeners a huge variety of color, a variety of single or double flower shapes from bell to flat, climbing and scrambling ability and fascinating, fluffy seed heads. That is quite a lot of wonderful attributes for one species to offer. A friend of mine in Levittown asked why she has been unsuccessful in her attempts to grow clematis. There can be a few reasons, such as not planting them deep enough or not giving them proper climbing support or not planting the right plants nearby to provide shade for their roots.
Let’s start with the plants themselves. How do clematis vines climb up trellises, arbors or obelisks? Clematis climb by grasping supports with their leaf stalks or stems. The vines themselves do not twine since they do not have tendrils. Their leaf stems twist around structures, but can only wrap around supports that are no thicker than ¾ inch. So in order to train clematis up a support, try using fishing line secured at the base then tie a small knot in the line every foot and secure to the top of the support. The knot will stop the clematis from slipping on the fishing line. Or attach a Slinky to the top of the support and let it wrap around the pole and hang to the ground. This allows the leaf stems to grow around and through the Slinky.
When designing with clematis, remember that they can be used in any size garden, even patio gardens can be brightened with a container grown clematis. Some smaller clematis, growing between 5’ and 7’, can be grown in medium large containers. Here are a few varieties to try: Fascination, Elsa Späth, Arctic Queen and Pistachio.
Clematis will tolerate part shady locations in the garden if there is enough dappled sun or reflected light available for them. In fact, they may produce brighter more vivid flowers when planted in part shade as the sun tends to fade their lovely colors. Some that actually prefer light shade are Nelly Moser, Frances Rivis and Comtesse de Bouchard.
Here are some hints to successfully growing clematis. Get a soil test to insure the pH is slightly alkaline and add some lime if necessary. Dig an 18” deep hole and set the plant so that the top of the root ball in 3” below the surface of the soil. This depth will reduce risk of stem rot and encourage the plant to send up more stems for a thicker, fuller plant. Mulch with a 4” layer of rich compost but keep the mulch 5” away from the stems of the plant. Other plants with aggressive roots can stunt clematis’s growth since they compete for water and nutrients. Refrain from planting species such as hosta and instead use shallow-rooted plants such as annuals at their feet to shade their roots.
The main enemy of clematis is clematis wilt, a fungal disease so avoid overhead watering. The fungus enters the stem just above the soil line and travels up the vine. As soon as you notice the vine wilt and start to turn brown or black, cut the entire stem at the ground level and dispose of it. If you have planted your clematis deeply as stated above, more stems will come up from the base. A few cultivars, which have proven resistant to clematis wilt include The President, Ville de Lyons, Nelly Moser and Jackmanii.
Even if you have tried to grow clematis before, it is worth trying again. In the first year clematis develop good roots, the second season the plant takes off and the third year it becomes your favorite. Every garden has room for at least one clematis. Give it a try and enjoy your blooming gardens.
Josephine Borut is currently on the board of directors of the Long Island Horticultural Society and is a past board member of the Long Island Rose Society. She is a current member of the American Rose Society, the Herb Society and the Long Island Horticultural Society, which meets on Sunday afternoon, with doors opening at 1:30 p.m. in the conference center at Planting Fields Arboretum in Oyster Bay. Meetings resume on Sept. 18, 2016. The speaker is Rick Mikula and his topic will be Attracting Beautiful Butterflies. For more information, go to www.lihort.org.