The many and varied forms of clematis

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By Sylvia Brockner

Last week we took a brief look at the white clematis, or Western virgin’s bower. This week we will take a look at a very similar plant known as yellow clematis or Chinese clematis, formerly Clematis orientalis. This is the plant that is on the noxious weed list and which so many people are concerned about.

First of all, it is not a parasite. It does not take any nourishment from the plants it trails over. It grows over other plants only to gain support to reach sunlight; in other words, it uses these plants as a ladder. The Chinese used this plant as a remedy for colds and sore throats. Chinese miners brought it to America and planted it in the Clear Creek Valley near Idaho Springs and Georgetown. It has spread from there up and down the I-70 corridor since the road was built, which provided newly disturbed soil along the creek banks. The stream and greater rainfall at that altitude made it possible for yellow clematis to get its roots down after germination until they could reach the underground moisture from the stream. It is a pleasing vine, with single yellow flowers shaped like paper Japanese lanterns. The fluffy white seed plumes also make the roadside attractive in autumn.

I know is difficult to eradicate, for I have one in my garden that I grew from seed many years ago. It seems to prefer stony soils and is therefore difficult to dig out, and any piece of root left in the ground seems to be capable of growing, so you only end up with more plants. I have tried to eliminate it, but it is very persistent; I have finally just given up. I enjoy the flowers and then prune them off before they produce seed. The other Colorado clematis is not as simple to identify, and most of them have been placed in new genera in the latest Weber. The yellow Chinese clematis is now classified as Viticella orientalis, which means little grape from the orient. Two other clematis vines have now been placed in the genus atragene. They are both weak vines that sprawl over the ground and have blue flowers. Atragene columbiana and Atragene occidentalis have been mixed up many times, and probably the easiest way to tell these two plants apart is the fact that occidentalis is mostly found north of the Arkansas Divide and columbiana is found south of the same divide. Another deep-purple blue former clematis, Clematis hirsutissima, is now Coriflora hirsutissima, and the form of this plant that is most common south of Colorado Springs is now named Coriflora scotte, giving it status as a full species. Both of these species are told from all others by their being more upright with no vine-like, creeping stems.

They are known by the common names of bush clematis, sugar bowl and leather flower, which refers to its thick, leathery petals. Hirsutissima means hairy, and scotti has white-bordered tepals and is common south of Colorado Springs. The original name of clematis was derived to honor two botanists, Edith and Frederic Clements, who ran the research station on Pikes Peak for many years.

Below is a list of our plants formerly known as clematis.

• Clematis ligusticifolia ee" Western virgin’s bower (cluster small flowers, white)

• Viticello orientalis ee" yellow clematis (cluster yellow flowers)

• Artragene occidentalis ee" blue clematis (single flower on stem)

• Astragene columbiana ee" blue clematis (single bloom, very similar to European, Alpina)

• Coriflora hirsutissima ee" sugar bowl, leather flower

(single, nodding, blue-purple)

• Coriflora scotti ee" sugar bowl, leather flower (white edges on tepals)

None of these are overabundant, except perhaps the yellow clematis, which almost always grows in stream valleys. Most of them are just coming into bloom now; the large flowers or cluster of flowers makes it easy to prune the heads off before the fluffy seeds are scattered by the wind.