Clematis of the Month for February 2013
Clematis ochroleuca is one of the easiest of the American native species to grow. This herbaceous perennial is very tidy in the perennial border growing only to 24 inches (60 cms). I like to use it near the front of my border. In most locations C. ochroleuca prefers a sunny location but in the hotter climates some afternoon shade is appreciated. It is one of the most widely distributed species in the viorna group, growing all the way from Staten Island near New York City, down the east coast to northeast Georgia. C. ochroleuca can be found in six different states though it is listed as endangered in Maryland. The many habitats of C. ochroleuca include thickets, disturbed soil, open embankments, rocky slopes, well drained woodlands, moist woodlands and open fields. Surely one of these conditions describes your garden.
This furry little gem was first described by W. Aiton in Hortus Kewensis in 1789. Ralph Erickson and Magnus Johnson classify C. ochroleuca as Section Viorna, subsection Integrifoliae. This group includes some very special and rare species including C. albicoma, C. coactilis, C. fremontii, and C. viticaulis. All of these are clematis that do not climb. C. ochroleuca has erect stems that are ribbed and have silky hairs especially closest to the leaf nodes. They develop lateral branches which enhances the number of flowers. The stems tend to be a light brown to a deeper violet brown. Another advantage is what I call ‘self pruning’. When I go out in the winter, I will find that the stems have pretty much disintegrated, requiring very little assistance on my part to be ready for new growth from the base in the spring.
In the hot, humid southern US where I live, clematis with unhealthy looking leaves is a major problem. This is not the case with C. ochroleuca. I have never seen mildew or worse for us, brown crunchy leaves on my plants. Their leaves are mostly simple, narrow to ovate and entire though some of the lower leaves can be coarsely serrated or three lobed. The 2.4 to 4.7 inch leaves are downy beneath, when young, but become more glabrous with maturity. Above the leaves are glabrous and somewhat reticulate. These subsessile leaves have acute to obtuse tips and rounded to cordate bases.
The flowers are charming little single, nodding urns of a whitish, greenish yellow color tending to a purplish tint near the base and the very long peduncle. The word ochroleuca means yellowish white.
The best part is that the sepals are covered in silky hairs on the outside. The four thin sepals are knitted together from the base to the middle of the urn, where they become more expanded and recurved towards the obtuse tip. The stamens are half the length of the sepals with green filaments and pale yellow stamens. The flowers bloom from late March to June for me, but the literature shows that in some areas it may bloom as early as April and as late as July. As with many perennials, deadheading will help the plant to rebloom, just be sure to leave some of those gorgeous seed heads to enjoy before the season is over.
The common name for Clematis ochroleuca is curlyheads from the fabulous persistent seed heads which appear as golden globes when backlit in the setting sun. The pilose achenes in varying shades of brown are orbicular to fusiform in shape with a narrow rim. The most attractive feature is the plumose fruit tail that are 3.5 to 5.5 cm long covered in yellowish to brown silky hairs which become expanded as they mature giving a curly fluffy appearance.
Clematis ochroleuca has been in cultivation for 125 years, isn’t it time for it to find a home in your garden?
Lyndy Broder