Written By Fred Hoppe, Board Master Certified Arborist WI-0556B
(Image Source: Neighborhoodgreening.org/start-seeing-buckthorn/)
What is all the buzz about buckthorn? Most people have heard of the plant that is prevalent in just about every county in Wisconsin. What is the big deal and how do we get rid of it and keep it away?
Buckthorn is an invasive plant brought here from Europe and northern Asia in the 1800’s. It was used as an ornamental shrub and also utilized for fence rows and windbreaks in agricultural fields. Since being brought to the United States buckthorn has invaded oak forests, riparian woods, savannas, prairies, old fields, roadsides, and just about everywhere in between.
So why is it so bad? Buckthorn has a broad environmental tolerance. It leafs out very early and retains its leaves late into the growing season, giving them a longer growing season than native plants. It also creates dense shade, eliminating the regeneration of tree seedlings and understory species. There is also evidence that it has allelopathic tendencies, that is, produces chemical compounds that inhibit the growth of other vegetation. The monoculture that is created by buckthorn growing unchecked and left to its own devices severely reduces the survivability of numerous other plants, especially native species. Not to mention that it creates increased maintenance in the areas where it grows, such as lot lines and along natural areas.
Best Options for Removal
What is the best way to get rid of buckthorn? The answer is, it depends on each situation. Some sites might just have a few plants, while others might be a forest. The size of the buckthorn and available tools are other determining factors when deciding how to get rid of the buckthorn as well.
On any site with buckthorn, one of the most effective options to get rid of it is to cut down the plants close to the ground and treat those fresh cuts with a systemic herbicide. Once the herbicide is on the fresh cut, it works its way through the root system and prevents that stump from growing back. If buckthorn that has been cut down does not have that herbicide application, it will most certainly sprout back, leading to the problem starting all over again.
Alternate ways of getting rid of buckthorn include foliar applications of systemic herbicide and cutting and smothering/covering of stumps to prevent resprouting. Foliar applications of herbicide can be particularly effective and easy on small buckthorn seedlings that have not gotten too large. Smothering and/or covering the cut stumps with heavy layers of mulch, cardboard, landscape fabric, etc, can be an option when herbicides are not wanted to be used.
With all these options, there will need to be continued vigilance and maintenance in the following years. Rarely, if ever, is buckthorn eradicated in one swoop. I typically tell people that buckthorn management is a lifestyle and not a one-time event. Where you see one buckthorn, it typically means that others are lurking below ground waiting to sprout, or the neighboring properties have it and those seeds can creep in. So be ready for follow-up maintenance!
With global warming and global commerce, buckthorn is not the only invasive species that we have to deal with. Several other plants are just as aggressive, including knotweeds and wild parsnips, just to name a couple. The tactics discussed today can help control those invasive plants as well.
A lot of homeowners and property managers can easily feel overwhelmed with managing invasives on their properties. Feel free to reach out to Hoppe Tree Service for a free consultation to help create a management plan that is right for you.