From soil preparation to choosing the right variety, there are many factors that go into choosing the best plant for your landscape. However, one factor that may go overlooked is whether a plant is invasive. Invasive plants can escape cultivation and spread to natural areas, where they displace native plant species. The loss of native species to invasive plants reduces wildlife diversity and also has direct impacts to humans. So before you plant this fall, consider first what you will be planting and whether it has the potential to become invasive.
What is an invasive plant?
Exotic plants are those that have been introduced to North Carolina from areas like Asia or Western Europe. Although most exotic plants are not invasive and can be safely planted in your yard, exotics can sometimes escape cultivation to colonize and displace native plants. When this happens, these plants are considered to be invasive. A great example is Chinese wisteria. Often planted for its fragrant purple spring blossoms, this aggressive vine can quickly spread to cover and shade trees and woodlands.
Many invasives are planted because of their attractiveness as ornamentals, their resistance to pests, and tolerance to tough environments. These same features can make them difficult to control once they escape into the natural landscape. Invasive plants are also attractive to wildlife, which feed on fruits and spread seeds to other areas. For example, fruits of Chinese privet are fed upon by birds, which spread seed to yards and natural areas. Chinese privet will quickly colonize and displace native plants, reducing both plant and animal diversity.
Know what to plant
Before selecting a plant, check whether it is invasive before installing it in your landscape. Although there is little information on the invasiveness of some species, there are a few that are not recommended for home landscapes. Trees such as mimosa, Bradford pear, and princess tree are known to be invasive. Invasive herbaceous plants include Chinese and Japanese wisteria, Queen Anne’s lace, and pampas grass.
Invasive plants, by nature are very difficult to control and are often expensive to treat with herbicides. The best way to help stop the spread of invasive plants is to avoid planting them. Even plants grown in different regions of the United States can be invasive in this area, so consider varieties that are native to this region when adding plants to your landscape.
Control the spread
If you have invasive plants in your yard, there are several ways you can control them. For some plants, continual cutting or mowing can exhaust stored energy in roots and eventually kill the plants, though this method often takes a year or more to be fully effective. Plant parts which have seeds or fruit should be cut, placed in a bag, and discarded in the trash. Avoid cutting plants that have gone to seed with a mower or weed eater as this will disperse seeds. Pull or spray any new weeds that appear.
Hardwood trees, shrubs and woody vines should be cut down and treated immediately with 15-20-percent glyphosate solution. If trees cannot be cut down, make several downward-angled cuts along the bark and “paint” or spray with a glyphosate solution. Glyphosate is the active ingredient in many nonselective weed killers.
Native plants do not become invasive and are particularly recommended if you want to encourage wildlife like butterflies and hummingbirds to visit your yard because they provide nesting habitat and high-quality food sources. Native songbirds such as the Carolina chickadee nest year-round and feed on seeds of native plants like goldenrod, pines, and yellow poplar. When properly placed in the landscape, plants native to this region often require less fertilizer and water, which helps save important natural resources.
When selecting plants for your yard, do not limit yourself to one type of plant. A diversity of plants that flower year-round is best because they provide color all year, as well as nesting sites and food resources for wildlife. North Carolina has nearly 4,000 native plant species, and even more exotic plants that are not invasive, providing many sustainable options for your landscape.
For help deciding if a particular plant is invasive and advice on controlling invasive plants, visit ces.ncsu.edu, where you can submit questions via the ‘Ask an Expert’ link, or contact your local Extension office. If you live in Pender County, call 910-259-1238. In New Hanover County, call 910-798-7660. In Brunswick County call 910-253-2610.
Sam Marshall is the horticulture agent with the Brunswick County Cooperative Extension of NC State University, College of Agriculture & Life Sciences.