Thursday, June 9, 2011

American Smoke Tree

As I was driving through Mount Auburn Cemetery yesterday, the ‘blooms’ of a cluster of American Smoke Tree, Cotinus obovatus, caught my eye. Actually, the true fertile flowers are past, but it’s the fuzzy remains of the infertile flowers that line the flower panicle that are providing the show. This tree is dioecous, meaning that there are separate male and female plants. All of the trees in this cluster appeared to be female, judging by the seeds that were forming at the ends of the panicles. I have not, to my knowledge, seen a male tree in bloom; however, at they say that the male is actually showier. So although you can be sure whether you are getting a male or female plant, either way the smoke effect will be striking.

A few seeds from fertile flowers are at the tips of the panicle.

Close up of the 'smoke'

The species name, obovatus, refers to the distinctive oval shape of the blue-green leaves. It grows as a small tree or upright shrub , 20-30 feet tall. Young tree have a fairly ungainly appearance. These trees are probably about 8 years old. When they were planted here about 3 years ago, they were gangly stems without too many branches. So they have developed very nicely in just a few years.

Buds forming on a younger plant in early May

The native distribution of C. obovatus is scattered across the south central U.S. It is found in neutral to alkaline well drained soils, but will tolerate the more acidic soils in New England, as well. This preference of alkalinity may make it a good choice for planting on residential sites, with their limed lawns and cement foundations.

More commonly seen is the Purple Smokebush, Cotinus coggygria, which mostly grows as a multistem shrub with broad purple tinged leaves. The American Smoke Tree is harder to find, I purchased mine last year from New England Wildflower Society, but I have also found it at commercial nurseries.

Cotinus obovatus at the end of October

While the smoke-like inflorescence is an attractive feature, the fall color of these trees is really the feature that will knock your socks off. This photo was taken of the same tree in late October last year.

So far I’ve planted two of these (one for me, one for a client) and I am looking forward to watching them mature.

1 comment:

Laurrie said...

Nice profile of a really pretty tree. Tower Hill Botanical garden has a nice small one, with a good shape (so it must have outgrown its ungainly stage). I need to go back in fall and see its autumn color.