By Chris Enroth
When we look at the current lists of plants that are deemed legally invasive by state and federal governments, we see species that were quite popular in the landscape in generations past. As we battle the current invasive species in our natural areas, there is a new generation of non-native shrubs that are quite popular in the home landscape which we are now seeing escape cultivation into the wild. Here are three shrubs that are recommended to avoid or remove.
Privet: I haven’t grown much privet as most Ligustrum species are hardy to zone 6. Which places the northern edge of most privet species south of my zone 5 garden. However, there are a few species such as Korean privet (Ligustrum ovalifolium) and common privet (Ligustrum vulgare), which are listed as being hardy up to zone 4. Privet certainly poses a problem in Southern Illinois, and there are increasing reports of privet invading natural areas in Central Illinois.
Traditionally, privet has been used as an evergreen hedge. Homeowners that have this plant in their landscape often laud its stellar performance. Conversely, landowners who work to eradicate escaped privet in natural areas curse this plant.
Burning Bush: Based on my experience, it seems like everyone has burning bush (Euonymus alatus) planted somewhere in their yard. It is often used as a hedge or foundation planting and it offers bright red fall color. Burning bush seedlings can commonly be seen popping up in landscape beds and anywhere else nature may take them. As I was weeding near the downspout of my house this spring, I noticed all the little seedlings were burning bush. If this shrub is this prolific in my yard, imagine those that escape into natural areas.
Japanese barberry: This is another very common landscape shrub. You may know Japanese barberry (Berberis thunbergii) by its purple-leaved forms such as “Crimson Pygmy” and the thorny nature of the stems. As I was walking along a wooded edge near my home, a green-leaved shrub stood out. Turns out it was Japanese barberry, only it had reverted to its normal green leaves. The only reason I figured it out was another escaped purple-leaved barberry seedling a few feet away.
Japanese barberry comes in many different shapes, sizes and colors. Often these are used in landscape beds or as an accent plant or as a screening plant.
Good Growing Tip of the Week – Even though the abovementioned plants are still completely legal to sell and grow in Illinois (as of spring 2021), there are lots of native alternatives. Inkberry holly (Ilex glabra) and Red Chokeberry (Aronia arbutifolia) are just a couple of examples. Check out the Good Growing blog for more detail on native shrubs at go.illinois.edu/GoodGrowing.