Woody invasives - ID and Control

​Japanese Barberry
– Very dense, deciduous shrub, growing anywhere from 2-8 feet tall.
– Flowers from mid April through May.
– Fruits (bright, red berries) are mature from July to October.
– Introduced as an ornamental in late 19th century and still sold in many nurseries and used by landscapers.
Common and Glossy Buckthorn
– Woody shrubs or small trees, forming dense and shady stands.
– Can grow 20-25 ft tall, 10 in. diameter.
– Brown/gray bark. Common buckthorn often has short, spike-like thorns. Glossy buckthorn is thornless.
– Small, dark purple-black berries that ripen in late summer and into fall months.
– Introduced as an ornamental. Some cultivars are still being sold.
Invasive Honeysuckle
– 6-15 feet tall, depending on species.
– Vines can reach 30 feet in length.
– Flowers from May to June. Dark red berries appear in late summer and fall.
– Also introduced as an ornamental.
Autumn Olive
– Can grown up to 20 feet tall and be upwards of 30 feet wide.
– Round shape with dense branches.
– Bright red fruits appear in September and into October.
– Native to Asia, introduced in 19th century for wildlife cover and food.
– Very little deer browse.
As you can see, these examples of woody invasives share many of the same qualities. They were introduced as ornamentals or wildlife habitat and quickly became out of control, forming dense thickets that crowd out the more desirable native species. Additionally, these species are all very shade tolerant and leaf out very early in the year. They then retain those leaves late into the fall. This makes it even more difficult for natives to flourish – with less sunlight, little access to moisture, and fewer nutrients. The best time to treat the woody invasives mentioned and others in this category is right now! Herbicides are most effective in the fall as long as they are applied no later than a month before the first expected frost. Cut stumps close to the ground and chemically treat the stub of larger plants. For smaller plants, and if you would rather not apply herbicide, hand pulling and digging may also be effective. It is important to remove the entire root system and not shear off any fragments while digging. Any remnants left behind often leads to resprouts the following spring! Regardless, hand pulling and digging often requires annual follow up to ensure continued control. Remember to be careful with invasive plant waste! Seeds can spread easily. Often the best way to dispose of removed plants is by taking them to your local landfill. Additionally, when using herbicide treatment, always follow the label directions closely!