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Why are some flowers called weeds, while others are desirable plants? A plant's behavior is as important as its appearance when it comes to answering this question. Plants that grow and reproduce too rapidly are becoming a serious problem. The following list contains plants that are invasive in Pennsylvania.
Characteristics of an Invasive Plant
Invasive plants are typically non-native plants that reproduce rapidly. They often choke out or eliminate other plants. Often they will grow in many different ecological niches, especially in disturbed sites. Most invasive plants are poor food and habitat sources for wildlife.
How Do I Know if My Plant is Invasive?
Sometimes a plant will show its invasive nature by spreading over, under, through, and into every possible space it can find. In these cases it is easy to identify it as an invasive plant. In other cases a plant may be more subtle. Burning bushes, privets, and amur honeysuckles look completely harmless in the landscape, yet if you check in nearby fields or forests you’ll find countless seedlings. Getting a professional opinion or checking a government list of invasive plants (available through the DCNR) is the best method to determine if a plant is invasive or not.
Coronilla varia (Crown Vetch)
Hesperis matronalis (Dame’s Rocket)
Lonicera japonica (Japanese Honeysuckle)
Lythrum salicaria# (Purple Loosestrife)
Miscanthus sinensis (Miscanthus)
Ornithogalum nutans (Star of Bethlehem)
Ranunculus ficaria (Lesser Celandine)
Trees and Shrubs
Acer platanoides* (Norway Maple)
Ailanthus alissima (Tree-of-Heaven)
Berberis thunbergii* (Japanese Barberry)
Buddleia davidii* (Butterfly Bush)
Celastrus orbiculatus (Oriental Bittersweet)
Euonymus alatus (Burning Bush)
Ligustrum spp. (Privet)
Lonicera maackii (Amur Homeysuckle)
Paulownia tomentosa (Empress Tree)
Pyrus calleryana* (Callery Pear)
Rosa multiflora# (Multiflora Rose)
Spiraea japonica* (Japanese Spirea)
* These species have some non-invasive cultivars
# On the Pennsylvania Noxious Weed List
If you have any questions about invasive plants just ask us the next time you're at the nursery. Our goal is to provide ecologically safe and responsible plants for our customers.
Sources: Compiled from experience, information from the Pennsylvania Certified Horticulturist Reference Guide, and
the Pennsylvania DCNR. For more information visit us on the web at www.behmerwald.com