Clusters of vibrant red fruit from sprigs of Oriental bittersweet and multiflora rose plants are traditional favorites for adorning holiday wreaths, garlands, and floral displays. But these non-native plants, two of many on Federal and State lists of 1514 invasive species, are considered noxious weeds.
Laws Forbid Noxious Wreaths
Oriental bittersweet and multiflora rose found in holiday decor can drop from displays and discarded decorations to overrun native populations when allowed to spread. Recent laws in Connecticut, Massachusetts, and New Hampshire prohibit the sale, import, purchase, and distribution of these and at least 140 other plants.
One Million Seeds From a Single Plant
Fruit and seeds, as many as one million produced by a single plant of multiflora rose (Rosa multiflora), fall from holiday wreaths and garlands displayed on homes and commercial buildings across the U.S. and enter the surrounding soil. Unmonitored, they can spread to neighboring parks and forests to disrupt the balance of delicate ecosystems.
Invasive Plants Threaten Native Blackberry and Raspberry
Mulitiflora rose is rapidly replacing native plants like the common blackberry (Rubus allegheniensis) and the flowering raspberry (Rubus odoratus). Anyone hiking through parks and national forests in the Northeast can note the widespread depletion of these native plants over the past thirty years.
Eco-Friendly Florists Keep Weeds Out of Holiday Wreaths
Local eco-friendly florists help protect the natural environment by refusing to implement noxious weeds into holiday wreaths, garland and floral displays. But consumers should be wary. Wreaths and holiday trimmings made in Japan, Korea, and Eastern China may or may not contain seeds or fruit of these harmful plants. Consulting local florists and government websites to identify invasive plants helps consumers purchase eco-friendly wreaths and holiday decor.
When Solutions Become Problems
Ironically, most invasive plants were introduced from foreign soils to help resolve U.S. horticultural and conservation problems. Little was known to predict the plants would eventually pose ecological threats. The multiflora rose was imported from Japan, Korea and Eastern China in 1866 as root stock for use in cultivating hybrid and ornamental roses. By the 1930s, the U.S. Soil and Conservation Service used the plant to help control erosion. Eventually dense thickets of the plant were used on interstate highway median strips as protective barriers to shield motorists from intense glare of oncoming traffic. It was distributed throughout rural areas as containment borders between pastures and farms.
Clinging Vines No Holiday for Native Plants
Oriental or Asian bittersweet (Celastrus orbiculatus) was introduced to the U.S. from Eastern Asia, Japan, China and Korea as an ornamental vine in the 1860s. It aggressively spread along meadow borders, pastureland, and invaded forests where it strangles low-lying vegetation as well as trees by blocking native plants from the sun. It is rapidly replacing native climbing bittersweet (Celastrus scandens) from New York south to North Carolina and as far west as Illinois. Oriental bittersweet has begun to spread in Washington and Oregon as well.
How to Prevent Spread of Invasive Plants
Preventing the spread of invasive plants begins with good consumer choices in purchasing eco-friendly holiday wreaths, garlands and floral displays. But if plants have already established themselves in native soil it is best to pull out younger shoots by hand and use repeated mowing or herbicides to control larger plant infestations. The multiflora rose is susceptible to rose-rosette disease but this has done little to contain populations. Oriental bittersweet, however, has no natural biological enemies on U.S. soil. It must be ripped from the ground and cut into small pieces before disposal.