Why are the leaves on my Clematis plant yellow?
Special to the Whig
Gail C. from Elkton asks: The leaves on my clematis plant are turning pale yellow, and have brown spots on the bottom of them. Would you be able to guide me in the direction of the problem?
Master Gardener: Clematis vines are fairly easy to grow and difficult to resist, given their eyecatching blooms. Some varieties produce saucer sized blossoms while others produce a wild profusion of color climbing up a trellis or spreading across a fence. There are over 300 varieties of clematis with a wide range of choices that will fill your garden with their beauty all season. Most varieties are vigorous growers and hardy for this area. Some are sun-loving while others do better in a shady garden. Many, to our delight, are scented.
A yellowing of leaves is most likely nutritional. Dan Long, longtime grower of garden vines from Brushwood Nursery, mentioned that many clematis are bred for the showy flowers with little regard to the foliage, especially for the summers we get here in the Mid-Atlantic. He said, “If it’s the lower leaves and the tops look OK, that’s probably just genetic and won’t change much. If it’s all the leaves, there could be a fertility issue.” He recommends Espona Rose-tone for clematis.
The long-time rule of thumb
for growing clematis (“face in the sun and feet in the shade”) is a way of saying welldrained, evenly moist soil that doesn’t dry out is best. An annual dose of organic matter and a top dressing of mulch will help keep the soil enriched and the roots shaded, cool and moist.
Clematis live up to 50 years or more, so location and careful planting is important. The hole should be at least twice as big as the pot and twice as deep. Mix some of the native soil from the hole with a topsoil and compost mix. Remove the clematis from its pot. Loosen the sides, but never pull on the vine or its training stake to remove it. Gently tease some of the roots away from the sides. Clematis roots run deep so plant the stem about two inches lower than the ground. Plant deeply for extra protection. Water the plant thoroughly. Settling soil can leave the vine exposed, so backfill if necessary. Carefully mulch when done — this is important because clematis need ample moisture and mulch will help the soil retain it. Water new plantings regularly during the first growing season for a good start.
Pruning the clematis is not as complicated as you might think. Use the flowers as a guide. Clematis flowers are divided into three major flowering groups: spring, early summer and late summer/fall. If you know when it flowers, you will know when to prune. Spring blooming won’t really need to be trimmed, but to tidy up the plant, prune right after blooming. Summer blooming clematis should be pruned in spring before new growth begins. Look for fat, healthy buds on sturdy branches. They usually begin 1 to 2 feet down from the top of the vine. Prune just above the healthiest buds. Also, trim away crowded and damaged canes at this time. Late-summer or fall blooming varieties should be pruned back hard in the spring to two feet off the ground. Look for healthy buds on sturdy canes and cut just above them. To train these into an arbor or other structure, they should be left longer.
Clematis attract many of the same pests as other garden plants. Consult with your garden center for the appropriate treatment of light infestations. A heavy infestation of damaging insects may be best treated by hard pruning of your vine. The only major disease that affects the large flowering varieties is called Clematis Wilt. One or more stems mysteriously wilt and die when infected. If this should happen, cut several inches below the dead stem. If the entire vine is infected, trim it to the ground. New buds will emerge from the crown underground. If you continue to have problems with wilt, consider some of the other species that are resistant to Clematis Wilt.
Each week, a Cecil County Master Gardener will write in to share their gardening experiences or answer a gardening question. To submit questions to the Master Gardener, send them to cecilmastergardener@gmail. com.
The clematis obvallata.