Enough with the Invasive Plants, Shrubs and Trees!

My first Blog here with Cuyahoga SWCD two-and-a-half years ago, was about how people should just say "no" to purchasing non-native plants, shrubs, and trees. Additionally, people should demand that big box stores and nurseries sell only native vegetation (for outdoor use) in the region they are located. My personal opinion on this matter has only grown stronger over the past couple years, especially after this summer, which is the first summer I became a regular user of a plant and tree identification app. I know that these apps have to be taken with a grain of salt since a photo may not always identify a plant, shrub, or tree correctly, however, I have found it to be a much quicker way of identifying and learning a variety of vegetation species.

My first experience with using this app, I went around my yard and began to identify all the different plants, shrubs, mosses, mushrooms and trees. There are far too many for me to even list, however, what I learned from identifying plants is that until you stop weed-whacking or chemically spraying areas you may think are “weeds” you may be surprised that what you are chopping down or killing, may actually be perfectly good native species. Even I was guilty at one point of time of weed-whacking White snakeroot [Ageratina altissima]. After years of letting it grow and finally being able to identify what it is, was truly an amazing experience. What was even more amazing was to learn that the plant was native, and even about the history of the plant with regard to its toxicity. While I truly enjoyed going around my yard and seeing all the different kinds of native plant species I didn’t even know I had, I also identified (on many occasions) plants that are not only non-native, but are also listed as invasive species according to the Ohio Department of Agriculture.

The first invasive species that popped up on my app while going around my yard was Multifloral Rose [Rosa multiflora]. Sadly, I thought that’s what it was, however, I believe that it was not planted, but rather was likely carried by a bird or other animal. Another invasive I identified was Amur honeysuckle [Lonicera maackii], which there were several, and, sadly, Callery pear [Pyrus calleryana], which there were also several, and these trees are planted far too much – especially for a tree which will be listed as invasive beginning in 2023. Yet again, I truly do not believe the Amur honeysuckle was planted, and I know for a fact that the four or so very small Callery pear trees were definitely not planted. Several other species that are not listed on the Ohio Department of Agriculture website as invasive – but that definitely could be, which I identified, are, Periwinkle [Vinca minor], Velvetleaf [Abutilon theophrasti], Japanese pachysandra [Pachysandra terminalis], Common burdock [Arctium minus], Bird’s foot trefoil [Lotus corniculatus], Wintercreeper euonymus [Euonymus fortueni], Burning bush [Euonymus alatus], both Bull and Canada thistle [Cirsium vulgare and Cirsium arvense), and English ivy [Hedera helix].

So, why are invasive plants, shrubs, and trees bad? According to the U.S. Forest Service, invasive species compete directly with native species for moisture, sunlight, nutrients and space. Establishment and spread of invasive species can degrade wildlife habitat, results in poor quality agriculture lands, degrade water quality, increase soil erosion, and they have contributed to the decline of 42% of U.S. endangered and threatened species, and for 18% of U.S. endangered or threatened species, invasives are the main cause of their decline. In my opinion, it is imperative that society does their part to minimize the spread of all invasive species. Everyone can do their part by minimizing the spread of invasive plant, shrub, and tree species. We can do this by identifying which ones on our properties are invasive, and by removing them. Additionally, if spot chemical treating is necessary, then we could also do this, however, my recommendation is first to remove the invasive species.

Around the yard is not the only place I have encountered invasive plants, shrubs, and trees. Aside from the many Callery pear trees planted on tree lawns and in yards, I have also come across this tree as a sapling within natural area easements. Additionally, in natural area easements, I have identified Narrowleaf cattail [Typha angustifolia], Common reed [Phragmites australis] (aka Phragmites), Garlic mustard [Alliaria petiolate], Cutleaf teasel [Dipsacus liciniatus], and Multiflora rose. All these species are currently listed as invasive by the Ohio Department of Agriculture. I assume that many of these species got in these natural area easements due to either wind or animals carrying seeds from these plants which may have originated on our own properties. For us to better manage these species in natural area easements, we must manage our yards, and do our best to identify and eliminate invasive species from our own properties. Of course, once established in these natural areas, if left unchecked, these invasives can possibly out-compete important native species.

Another area where I have become accustomed to encountering invasive plants, shrubs, and trees are in post-construction detention and retention basins. While the purpose of these basins is stormwater management, many of these basins are not properly maintained, and become an unwanted sanctuary for invasive vegetation. The common encounters at basins are Narrowleaf cattail, Phragmites, Cutleaf teasel, and Purple loosestrife [Lythrum salicaria], but I have also identified Autumn olive [Elaeagnus umbellate] on a basin embankment, as well as Tree-of-heaven [Ailanthus altissima] also on a basin embankment. Additionally, within retention basins, I have identified Curly-leaved pondweed [Potamogeton crispus], as well as Eurasian watermilfoil [Myriophyllum spicatum], and Hydrilla [Hydrilla verticillate]. These stormwater management basins should not only be maintained in order to properly function and manage stormwater the way they are designed, but also to not be a haven for invasive species. We need to do our part by minimizing the spread of invasives, and properly maintaining stormwater management basins is the right thing to do in order to help minimize the spread of invasives -- especially since the number of stormwater management basins is continually increasing.

Lastly, I have also frequently come across invasives while on active-construction sites. Invasive plants, shrubs, and trees tend to thrive in areas of disturbed soil. Unfortunately, although exposed soil should be stabilized (such as with seed and straw) within one week of its most recent disturbance on construction sites per Ohio EPA Permit: OHC000005, often this does not occur. Areas of exposed soil tend to fill in with invasive vegetation. Tree-of-heaven, Common teasel [Dipsacus fullonum], and Cutleaf teasel, tend to take-over areas of exposed soil, along with other invasives (just not designated as invasive on the Ohio Department of Agriculture website) such as Canada and Bull thistle, Common burdock [Arctium minus], and Common mugwort [Artemisia vulgaris]. Additionally, narrow-leaved cattail and phragmites are still far to commonly observed within temporary sediment settling ponds on active construction sites.

As I have mentioned, everyone shares the responsibility of minimizing the spread of invasive plants, shrubs, and trees. Do not plant invasives. If invasives exist on your property, see that they are properly removed and disposed of – such as disposing them in a heavy-duty garbage bag or contractor bag. There are many different articles that tell different stories with regard to composting invasive plants. My opinion on this matter is, if the invasive seeds have a chance to survive the composting process, then it should not be done. I strongly recommend throwing invasives into a contractor bag, make sure that the contractor bag is tied tightly, and dispose of it into the trash. Areas where invasives are removed should be re-planted with native species. Monitoring these areas for pop-ups of future invasives will also need to occur.

Blog Author: Chris Vasco, Urban Conservationist

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