Lone Rose Eradication

It’s not unusual while out walking to come across a single specimen of an invasive plant. How to handle the situation seems to be a subject of some debate. A good example is this lone Multiflora Rose that I found in the woods. At the moment, this rose isn’t causing much of a problem. Lack of sunlight has caused it to produce long, spindly canes and there is no evidence of fruit production. In time, the canes may catch in tree branches where they will be supported. Future growth will move up through the tree in like manner until sunlight is reached. Then fruit will be produced and the birds will begin distributing seed in the surrounding area. It’s just as likely that the rose will eventually die, but I always expect the worst.

Four of the seven canes on this rose are already dead. This is typical of roses growing in the woods. The bushes seem to go into a cycle of decline and resurrection. Early season growth is rapid because of the more open woodland canopy. When the canopy closes in mid-summer, energy production is reduced and the rose becomes stressed. The result of the stress can be die-back of top growth or a reduction in root mass. In either case, the plant takes a step backwards and has to rebuild itself. The speed at which these things occur varies depending on weather patterns and other environmental factors.

Just cutting the canes off at the base is a waste of time. This action causes little harm to the rose and sprouts will quickly grow to replace what was removed. Multiflora Rose also has the ability to develop shoots from shallow surface roots. A severe pruning may just invigorate the bush and result in even more canes.

Years ago, I did some experimentation with manual removal of rose plants and found that buried roots had a very small chance of surviving to produce new top growth. I also discovered that this manual removal was only practical on medium sized plants with a base that wasn’t much bigger than my fist. Before doing any cutting, I use my knife to loosen the soil and trace the pattern of the roots. My goal is to cut all roots at a point enough below the soil surface that they are unlikely to sprout.

There’s always a vertical root beneath the base of the plant. I start by jabbing my pruners under the base and cutting the main root. I then follow the horizontal roots outward to the point where they are covered by about an inch of soil and cut them. In case you're wondering, the knife and pruners are always with me when I walk.

After removing the plant, I spread the leaf litter back over the bare soil. Some criticize this method by saying that the rose will grow back. I’ve already learned that it rarely regrows and if I haven’t killed it, I’ve surely given it a significant set-back. Others criticize that I’ve created an area of disturbed soil into which a seed from an invasive plant can fall and take root. I think that having conditions where an invasive plant might develop is a much better situation than already having the invasive plant in place. I do things because they produce positive results for me on my property. There are so many unique variables in play that it’s often hard to see why a particular management method is successful one place and a failure in another. That’s why I always apply new management techniques in small doses and carefully monitor the results before deciding if the method is good or bad. As for the Multiflora Rose, even if all I accomplished was to delay its dominance by a couple of years, I can’t just walk away and leave that one plant in an otherwise invasive free setting.

Multiflora Rose Clearing Site

This is the site where I went in last winter and cleared out my last really big patch of Multiflora Rose. Instead of a mass of invasive shrubs, I now have a nice mix of native vegetation. I think it was well worth the scratches and blood loss required to get the job done.

Last year at this time, a shot from this position would have shown a solid wall of Multiflora Rose leaves directly in front of the camera. I came in here twice during the spring and sprayed glyphosate on all the rose sprouts I could find. I must have done a pretty good job, because there are no rose canes sticking above the other plants. An untreated rose stump would have eight foot canes by now. I’m not naïve enough to believe there aren’t any little roses in there, but I’m happy with the degree to which they’ve been knocked back.

My favorite part is the mass of Jewelweed that now blankets much of the area. Jewelweed is an annual that has been here in low numbers in the past. The ground beneath the roses must have been covered with seed just waiting for its chance to grow.

The bright orange flowers remind me of molten lava. Even in the shady habitat preferred by this plant, the flowers shine as if on fire.

The deep flower with its curled tail forces nectaring insects to go far into the tube for a meal. This insures good contact with the flower’s reproductive parts and increases the chances of successful pollination.

Of course, some animals are designed to easily access these deep flowers. Several Hummingbirds were utilizing this patch.

An interesting feature of Jewelweed is its method of seed dispersal. The pods are composed of several thick strips that are joined by a thin seam. As the seeds reach maturity, the seams weaken and eventually part. The break in the seam allows the thick strips to curl rapidly and sling the seeds away from the plant. Some other plants utilize this same technique, but Jewelweed pods are larger and make a more interesting display.

Remnants of an exploded pod. Tapping or squeezing the pods can initiate the explosion and seeds are ejected with surprising force. I once saw a naturalist demonstrate this phenomenon to a group of college students. Following the demonstration, one student put his face down close to the plants and then tapped a pod with his finger to make it explode. There was no permanent damage to his eyes, but I remember the naturalist making a comment about stupid college kids.

It’s really fun to walk past this site and observe native plants and animals. I didn’t really think that the site would respond so quickly to the removal of the Multiflora Rose. I guess there were a lot of stunted plants hidden in there just waiting for me to release them.

Roses

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.