HARRISBURG, Pa. — Multiflora Rose is a problem on many farms throughout Pennsylvania. Originally introduced as a living fence for wildlife habitat, this weed soon became the state’s No. 1 noxious weed.
Recently, the Farm Service Agency has been receiving inquires on how to control Multiflora Rose. This is especially important to participants whom are required to control noxious weeds on contract acres.
The following information is derived from a USDA fact sheet and should help landowners understand how to control and eliminate Multiflora Rose.
What is it?
Multiflora rose (Rosa multiflora) is an invasive shrub that can develop into impenetrable, thorny thickets. It has the distinction of being among the first plants to be named to Pennsylvania’s Noxious Weed List.
This plant was introduced from Asia and widely promoted as a ‘living fence’ to provide erosion control and as a food and cover source for wildlife. Multiflora rose does provide cover and some food value with its fleshy fruit (called ‘hips’), but its overall effect on habitat value is negative.
Multiflora rose is very aggressive, and crowds planted grasses, forbs, and trees established on acres to enhance wildlife habitat.
There are least 13 species of rose that that grow ‘wild’ in Pennsylvania, and most of them are desirable in a wildlife habitat planting.
Telling them apart
Multiflora rose is readily distinguished from other roses by two features — its white-to-pinkish, five-petaled flowers occur in branched clusters, and the base of the leaf where it attaches to the thorny stem is fringed.
Memorial rose (Rosa wichuraiana) is the only other species with a fringed leaf base, but its flowers are borne singly. Individual plants can easily grow to more than 10 feet tall and 10 feet wide.
When they grow singly, multiflora rose plants have a mounded form because of their arching stems (Figure 2). When the tips of the stems touch the ground, they can take root (called layering) and form a new crown. If near trees, the rose behaves almost like a vine, and can grow 20 feet into the tree. Multiflora rose breaks bud early in the spring, quickly developing a full canopy of compound leaves that have seven to nine leaflets. Peak bloom is in early June.
Birds and browsing animals eat the fleshy, bright red hips and the seeds pass through their digestive systems intact. These seeds can remain viable in the soil up to 20 years.
Control measures
A single-method control approach will not eradicate a multiflora rose infestation. Like other invasive species, a combination of control tactics is necessary to manage this plant.
Finding multiflora rose early is the best way to simplify control. Controlling rose as small, scattered plants is much easier than trying to eliminate established thickets.
Vigorous, competitive vegetation greatly aids control as well. Brush mowers, or similar equipment can be used to cut and pulverize the top growth of established plants.
Mowing alone will not control multiflora rose, but it is a great way to make it easier to treat the plant with herbicides.
Top growth of smaller plants can be removed with conventional mowing equipment. Herbicides can be applied to rose foliage or to the stems. Applications to foliage can be spot-applied with a hydraulic sprayer with a handgun, mounted on an ATV, tractor, or truck; or a backpack sprayer.
Spraying
In a grassland planting, treatments of the herbicide Cimmaron (metsulfuron) mixed at 1 ounce per 100 gallons of spray solution will be very effective. Apply this solution uniformly to the rose foliage, so that it is visibly wet, but the solution is not running off the foliage. Avoid treating the surrounding vegetation.
Metsulfuron is extremely effective against rose, but it will cause injury to adjacent grasses if you contact their foliage during the application. In tree plantings, there is some risk of injury by metsulfuron through root absorption, so a glyphosate (Roundup Pro) treatment is a better choice.
If either metsulfuron or glyphosate is accidentally applied to the foliage of the trees, severe injury will result. When treating multiflora rose, you should also target any other undesirable woody species in your plantings.
Metsulfuron in combination with glyphosate provides an effective treatment against a wide spectrum of woody and herbaceous species.
Another approach
A more selective, but more expensive treatment is a foliar application of the combination of triclopyr + 2,4-D (Crossbow). Apply Crossbow as a 1 percent mixture (one quart in 25 total gallons of spray solution) to multiflora rose in grassland plantings on a spray-to-wet basis.
The ingredients in Crossbow will not injure adjacent grasses. This treatment is more likely to cause injury if used in tree plantings than a glyphosate treatment.
The herbicide triclopyr (Pathfinder II) can be applied to multiflora rose stems to kill the top growth, either after cutting, or to intact plants as a basal bark application. For either application, apply the ready-to-use Pathfinder II to wet the stems, but not to the point of run-off.
Stump treatment is a very effective way to enhance a mowing treatment. Pathfinder II is oil-based, and can be applied after a mowing to prevent regrowth. The oil solution penetrates the bark of the rose stems and kills the tissue underneath, preventing sprouts.
You can apply this treatment with a squirt bottle, but if you have a lot of crowns to treat, it’s much easier to use a backpack sprayer.
When it’s acceptable to leave the top growth of the rose in place, and when you can actually access the base of the plant with a spray wand, you can control multiflora rose with a basal bark treatment.
Apply Pathfinder II to the lower 12 inches of all the stems, completely wetting each stem, but avoiding run-off. Basal bark treatments are best applied from January up to the point of fall coloration.
Keep at it
After making your initial control applications, it is essential to follow-up. If you don’t, multiflora rose will re-establish. Where rose was dense, it is unlikely you were able to thoroughly treat all the plants while trying not to get tangled in the thorny stems.
When spot treating, it’s easy to miss a few stems. When stump treating after mowing, it’s almost impossible to find all the crowns that need to be treated.
Don’t get complacent. If you had a significant infestation, only ongoing maintenance will prevent it from returning.
I don’t know if this is still an active website, but if you do get this,we would like to get an answer to this question..How soon after spraying folage with crossbow can you brush cut the dead appearing stems?