Friday, June 19, 2009


I’ve been out taking an inventory of the Roses of Blue Jay Barrens. I’m not doing this to enjoy the beautiful blooms or the lovely fragrance, since there are no blooms now. I’m searching for those Roses that are not welcome to live here. The unwelcome guest is Multiflora Rose, Rosa multiflora, shown above.

I do a lot of hands-on management at Blue Jay Barrens in an effort to encourage the growth of native plant species. Most of the intense stuff is done during the winter so my activities don’t do damage to the actively growing plants. During the summer I do a lot of evaluation of the previous year’s activities and planning of activities for the coming year. It seems as though one of the most common activities associated with managing land for native flora is killing plants. There is a constant competition amongst plants for available growing space. In order for one plant to thrive, others must die. Non-native plants that offer a lot of competition to the natives are usually labeled as invasive species. One of the worst at Blue Jay Barrens is Multiflora Rose.

If you are going to begin eliminating invasive species it is vital that you be able to clearly identify that species among others of similar appearance. Multiflora Rose produces two types of growth, short leafy branches that bear fruit and long branches that grow up, then fall over to form an arch. If you were to confuse Multiflora Rose with any other species, it would probably be the Prairie Rose, Rosa setigera. Prairie Rose also displays the tall arching branches. Many Prairie roses have been killed by people mistaking them for Multiflora.

The easiest way to tell the two apart is to look at the stipules of the leaves. A stipule is a wing-like structure beginning where the leaf attaches to the branch and running a short distance along the edges of the leaf stem. That of Multiflora Rose, shown on the left in the photo above, bears long branching filaments, while Prairie Rose stipules show a uniform margin, coming to a point in the direction of the leaflets. Prairie Rose also tends to have a straight thorn while that of Multiflora is usually hooked. This helps identify the plants during the leafless period.

This bush is infected with rose rosette disease, which was predicted to sweep the country free of multiflora rose in the late 1980’s. Infected plants typically show clumps of distorted sprouts with a yellow or red coloration. The disease will kill the plant after a few years. The problem is that the disease is carried by a mite that lives on the multiflora rose bush and that mite is not very mobile at all. It’s hard for a diseased bush to infect another bush even a few feet away. The second problem is that new bushes develop much faster than the infected ones die.

Three species of rose have been found living at Blue Jay Barrens. The third is the Pasture Rose, Rosa Carolina. The Pasture Rose grows to several feet on sites with available moisture, but rarely reaches a foot tall in the dry prairie areas. This species does not produce the tall, arching canes.

I’ll map the Multiflora Rose locations so I’ll know where I have to spend some of my time this winter. We’ll discuss control techniques then.

No comments:

Post a Comment