Blooming flowers, emerging leaves, sprouting seedlings, and peeping frogs are just a few of the signs that encompass the magic of the spring season for me. As nature goes through the motions and awakens, I hope you have found some time to get outside and enjoy the wonderful gift of the changing seasons. Unfortunately, I’m always disheartened to see the number of invasive shrubs that are dotting the landscape this time of year. Spring is an easy time to see firsthand how invasive plants often break dormancy before native plants, which basically means that they leaf out earlier and have an automatic leg up as they are growing a few weeks before other plants. For more information, read Invasive Shrubs in Northeast Forests Grow Leaves Earlier and Keep Them Longer from Penn State.
Q. What shrub has yellow-white (sometimes pink), trumpet-shaped flowers in mid-spring that smell sweet?
A: Exotic bush honeysuckle is a large category of several different fast-growing species (Lonicera maackii, L. morrowii, L. tatarica, L. xbella, L. fragrantissima) that are perennial, deciduous shrubs that can grow up to 20 feet in height. These species share many of the same characteristics — yellow to white, sometimes even pink-colored flowers, sweet-smelling flowers, and red to yellow berries in early summer. Leaves are opposite on the stem. Wildlife such as deer and birds are known to spread these invasive shrubs by eating the berries. If you look underneath utility lines or at the forest edge, you will often see these invasive shrubs.
As of February 2018, the Maryland Department of Agriculture classified Amur honeysuckle (Lonicera maackii) as a Tier 1 invasive plant in Maryland. A person may not propagate, import, transfer, sell, purchase, transport, or introduce any living part of a Tier 1 invasive plant in the state. For more information visit the University of Maryland Extension page about Exotic Bush Honeysuckles. For control information, visit Invasives In Your Woodland: Bush Honeysuckles.
Over the last 5 years, I’ve seen a huge increase in the number of invasive shrubs in my own woodlot, which is secluded from homes due to the mountainous terrain. Nonetheless, Japanese Barberry (Berberis thunbergii) has begun taking over the understory and edges of hayfields. I believe that it was spread by wildlife. Did you know this shrub gets small yellow flowers in early spring and then red berries?
Q. I see Japanese barberry planted in many landscapes. Is it really an invasive plant?
A: This invasive shrub has been used in landscapes in North America since the late 1800s. It is very popular because it provides resistance to deer browse and can grow in a wide variety of light and soil conditions, making it a plant that can be used dependably in home landscapes. However, these characteristics contribute to its aggressive nature when spreading into natural areas. It forms dense foliage thickets that create an ideal humid environment for black-legged ticks (deer ticks) which can carry the pathogen that causes Lyme disease.
The Maryland Department of Agriculture (MDA) has named this a Tier 2 invasive plant. This classification means retail stores that offer this plant for sale must display a required sign indicating that it is an invasive plant. Landscapers may not supply Japanese barberry unless they provide the customer with a list of Tier 2 invasive plants. In our neighboring state of Pennsylvania, Japanese barberry is on the noxious weed list and will be banned for sale beginning this fall.
Visit the University of Maryland Extension website for more information about Japanese barberry and how to control it.
Q. I want to add a shrub to my landscape that provides berries for the wildlife and fall foliage color. Is burning bush (Euonymus alatus) a good choice?
A: Unfortunately, winged burning bush (Euonymus alatus) is not the best choice when adding a new shrub to your landscape, as the Maryland Department of Agriculture (MDA) has named this a Tier 2 invasive plant. This classification means retail stores that offer this plant for sale must display a required sign indicating that it is an invasive plant. Landscapers may not supply winged burning bushes unless they provide the customer with a list of Tier 2 invasive plants. It is also important to note that burning bush is now a banned noxious weed in our neighboring state of Pennsylvania.
For more information, check out this previous blog post, Q & A: Is Burning Bush an Invasive Plant? For control suggestions, refer to Invasives in Your Woodland – Winged Euonymus.
Q. Does Heavenly bamboo support wildlife with its evergreen leaves and red berries?
Heavenly bamboo, sacred bamboo, or Nandina (Nandina domestica) has berries that are actually toxic to cats and also cedar waxwing birds. This plant was introduced from Asia in the early 1800s but it outcompetes many native plants with its aggressive nature.
MDA has named Nadina a Tier 2 invasive plant. This classification means retail stores that offer this plant for sale must display a required sign indicating that it is an invasive plant. The Nandina cultivar ‘Firepower’ is the only exception.
For more specifics about this plant, read Not so Heavenly from the Maryland Invasive Species Council. The Master Gardeners of Northern Virginia have a good list of native alternatives to plant instead.
All of these invasive shrubs produce berries which is one of the ways they spread so widely and easily. Please research plants before adding them to your landscape. Below are links for information on finding non-invasive plants:
Native Shrubs – University of Maryland Extension
Landscaping with Native Plants- Maryland Native Plant Society
Keystone Plants by Ecoregion- National Wildlife Federation
Resources on invasive plant identification:
Plant Invaders of the Mid-Atlantic Natural Areas (PDF)
Check the University of Maryland Extension website for an Introduction to Invasive Plants in Maryland for more information on how to reduce them.
By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland. Read more posts by Ashley.