Invasives Watch

A number of invasive plants can be controlled effectively in late fall and early winter, as discussed in The Garden Shed’s Invasive Plant Control Calendar. The methods to be used include cut stump, hack and squirt, and basal bark. These methods may be employed at any time of the year except for early spring when the sap starts flowing upward to the leaves. For detailed guidance on how to use each of these methods, including types and amounts of herbicides to use, see Controlling Invasive Plants Effectively & Safely with Herbicides/Blue Ridge PRISM.

Autumn Olive (Elaeagnus umbellata):  According to the Blue Ridge PRISM,  “Autumn olive can be controlled at any time of year, except during spring growth, by cut-stumping or hack & squirting.”

Cut-Stump method: “Cut or saw all stems to several inches from the ground and immediately spray cuts with a concentrated recommended herbicide.”

Hack & Squirt method:   “Make hacks 2 inches apart in stem circumference and apply concentrated herbicide.

Asiatic or Oriental Bittersweet (Celastrus orbiculatus)  is best treated with either cut stump or hack and squirt.  Spraying large vines is not recommended.

Callery or Bradford Pear (Pyrus calleryana ‘Bradford’) can be treated from fall into early winter by using cut stump, hack and squirt, or basal bark methods.

Chinese Privet (Ligustrum sinense) is an evergreen to semi-evergreen shrub, growing 15-30’ tall, that can form large stands and thickets. As indicated in the Invasive Plant Control Calendar article, “From November to January, after deciduous plants have dropped their leaves, cut larger privets down to a manageable size and apply a recommended foliar herbicide at a concentration higher than is needed to control most invasive plants. The cut stump method with an herbicide application to the cut, or a basal bark treatment are also effective methods and can be applied anytime except early spring.”

Japanese Honeysuckle (Lonicera japonica) “is best treated with foliar sprays from autumn to early winter after most native plants have lost their leaves or are dormant, but before a hard freeze (24°F). For the cut stump method, sever thick vines near the ground and treat the cut ends with a recommended concentrated herbicide from early summer into winter.” Invasive Plant Control Calendar.

Porcelain-Berry (Ampelopsis brevipedunculata)  “From fall to winter, cut stump bigger vines and apply an herbicide immediately after. If you can reach the largest stems in the tangle, you can also use a basal bark application. Apply a concentrated, recommended herbicide mixed with horticultural oil to the lowest 12” of the stems; no cutting is needed. Be careful not to spray nearby desirable plants.” Invasive Plant Control Calendar.