Fighting invasives in theory and practice
- Turtle in Chief
- Feb 14, 2022
- 4 min read
For me, winter is a time for fighting invasive species. Since they often remain green in winter they are easy to locate, and access is less of a problem because other vegetation has died back or been pressed down by snow. Also there is time now before the explosion of spring tasks.
I've noticed that the debate over invasives is usually presented in a theoretical arena with positions chosen on the basis of abstract beliefs. There is little gray area between the two allowable positions which I call Let-everything-grow and Kill-everything-not-native. On the former side are those who believe Mother Nature knows best and everything happens for a reason--kind of like replacing the Christian god with Mother Nature and leaving everything in Her hands. On the other side are the Vegetative Puritans who desire the eradication of all introduced plants.
This framing of the controversy mirrors current "debate" in politics where there are two opposing sides and no room for nuance. (You're either for it or against it.) Newcomers to the subject are sucked in and not asked to actually think about anything. Luckily this isn't how the real world works. I'm sure there are many land managers applying critical thinking skills following real life observations to make decisions to remove plants or not. I would like to think that of the folks out there doing real work, very few fall into the two categories described above.
My take on invasives is nuanced to say the least, and would no doubt invoke the ire of both sides should I foolishly decide to participate in the discussion. I spend much of my time budget for removals on Japanese honeysuckle for the simple reason that it hurts trees. Lonicera japonica impedes forest regeneration by engulfing saplings and pulling them to ground. I can make a big difference in a small amount of time by cutting the vines to release the trees to grow freely. The dreaded garlic mustard, on the other hand, I almost completely ignore except to pull it out of vegetable beds. It is ubiquitous in the spring in the woods by the river, plants probably numbering in the tens of thousands, making eradication a laughable endeavor. Any time spent on it is totally wasted.
Other invasives fall somewhere on the continuum between total abdication and fighting the good fight. Multiflora rose presents an interesting case. It can facilitate reforestation attempts by protecting seedlings from browsing deer. Yes, it is not native, is considered invasive, and has nasty thorns, but it offers a service. As the saying goes, "The thorn is mother to the oak." Furthermore it likes sun and will decline as neighboring plants grow and cast more shade. When it has grown up high using tree branches as a ladder and is still thriving in thick woods, I cut it at the base. In the open savanna I leave it to grow and in the spring I will plant tender seedlings under each tangled mass. At any point it can be cut at the base and left in place to function as a natural cage. Knowing that it will soon be shaded out, why not get some good out of it while I can?
Callery pear can be used the same way. Ray Major of Trees from Seeds
recommends cutting them at 2 to 3 feet from the ground. This makes for less stump sprouting, and the tops can be used for dead hedges to protect young plants from deer. Just pile up the thorny branches and plant within. I plan to use bush honeysuckle and autumn olive in the same way. I fully understand that the original plants will not die and will require more cutting back to keep them from reaching reproductive age and spreading further. The fact is that these plants are ubiquitous in my area; eradication is impossible and it is not my goal. Even if I could kill every invasive on the property with massive amounts of herbicides, they would almost certainly return because that's what invasive plants do. I manage with an eye on the long term goal of more native species richess, and a greater percent of overall biomass consisting of natives, not complete elimination of invasives.
Autumn olive is a plant that falls into that gray area that brings discomfort to the Let-everything-grow and Kill-everything-not-native camps alike. While I intend to eventually remove the maximum amount possible, I acknowledge that it has benefits such as adding nitrogen to soil. This can be exploited by more desirable plants when the olive is cut back and the nitrogen becomes available. Another benefit on my low lying land is erosion control. There is a lone autumn olive growing in a spot prone to sink holes. I will not remove this plant--for obvious reasons--until nearby pawpaws and maples get established there.
One important purpose that vines, brambles, and brushy plants serve is deterring bucks from rubbing. Though I seldom see them, I know bucks are present due to wounds on young trees. For reasons unknown to me, our whitetails prefer staghorn sumac above all other trees for rubbing. Dead and dying stands of young sumac dot the savanna. Not realizing the service it was providing, I once removed multiflora rose from a gorgeous young sumac, probably the largest on the property. Unfortunately this tree has now sustained major wounds from rubbing and may not recover. This incident has made me even more mindful of possible consequences of plant removal.
The process of habitat improvement and land restoration is a marathon, not a sprint. Too many times the need for immediate results and an obsession with native purity leads to extensive use of herbicides. The Kill-everything-not-native folks are often loyal chemical company customers. On the other hand, lack of understanding of native flora and fauna ecology means means the Let-everything-grow crowd stalls progress by allowing invasives to impede succession. Realizing the issue isn't black and white will help. More gray areas please!
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