Good Invasive/Bad Invasive



Among the many handwringing issues popular with today’s paranoid society is the issue of invasive plants and animals. Not to mention invasive human beings. The matter came to a head in California recently over a kind of eucalyptus tree that grows there. Forests of these trees are now deemed to be fire hazards. Clear them out, says one side of the debate.  They’re an invasive anyway and don’t belong here.

How so? The natives who have lived with this eucalyptus as long as they and their ancestors can remember, disagree. They love their trees and want to keep them. It is true that this species is not “native” to the area. It only arrived there a century or two ago from Mexico. And therein hangs the plot. How long ago does an invader have to invade in order not be an invader?

Nor is it easy to say that just because an invasive is a “foreigner” that it is bad for the “natives.” Canada thistle invaded America (from Europe, not Canada) and has become one of our most pestiferous weeds. But bluegrass and white clover are also invasives and surely among our most beneficial plants. Emerald ash borers and a host of other invasive bugs are bad business for native forests, but remember that the honeybee is not a native either. To make matters more complicated, some of our native plants can be just as “invasive” as the invasives, like for instance boxelder, prickly ash and gooseberry. Lovers of oak savannahs consider maple trees to be invasive and in a way they are because they grow fast— especially red maple— even in the shade where they crowd out sprouting, sun-loving oaks, hickories and walnuts. To confuse the issue even further, some species can be both invasive and non-invasive. If you let European bittersweet gain a foothold in your woods, it can engulf everything and entwine and kill your trees. On the other hand, American bittersweet, which has narrower leaves and fruit clustered at the ends of the stems, not strung out singly all along the stem as in the case of the European type, will grow up into the trees much less vigorously and not harm them. It is much prettier for decoration too.

So what’s a garden farmer supposed to do? If you have honeysuckle taking over your woods, should you introduce European bittersweet and watch the two green devils kill each other? If you have a little plot of woodland or native prairie that you want to maintain a certain way, you can weed out the undesired plants by hand. Or do controlled burnings. Or spray a lot. You may win the contest, at least for awhile, but don’t bet on it. I read a most interesting magazine, “Woodland & Prairies” about people who do that, but it is very hard work.

As more and more people move around the world, more and more invasives will move with them and there will be compromises that native purists will have to accept. Sometimes what looks like a terrible problem may be only a temporary situation that in time takes care of itself like Dutch elm disease seems to have done. Elm trees are coming back in my woods because after all the older ones died off, so did the bug that killed them. I have watched red and sugar maple trees invade my two woodlots. Sun-loving trees can’t get started under their heavy shade, but on the other hand, that awful wild mustard and multiflora rose are almost gone where maples dominate. We can walk freely under the trees now and on a carpet of gold in the fall. There are still some tall hickories and oaks producing seed and I assume they will survive when storm, fire, or disease makes an opening among the maples. After all, both oaks and the maples have found a way to exist here nearly forever.

And, as distasteful as the memory is, white settlers were an invasive into America. And their diseases all but wiped out some native tribes. Invasive plants and invasive humans have a lot in common.


I love the honeysuckle too–it’s beautiful and it’s heady scent fills the spring air. And yes, the birds and the bees and other insects love it too–makes the honey taste so good!

Much as I’d love to get rid of the honeysuckles on my place, I don’t. The birds love nesting in them.

Great perspective, as usual, Gene. If anyone knows of a use for bindweed, please let me know!!

I’ve talked with local old-timers about farming in my county — heard great stories about one-eyed mules and share cropping — and one topic that always comes up is about how many crop pests today weren’t here when the old-timers first started farming, and the pests all have words like “European” or “Asian” in their names. My farming friends are definitely unhappy with the non-native (from other continents) insects that damage their crops!

We have a new pest now — Kudzu Bug (Asian in origin) — that is causing all kinds of trouble in the soybean fields. The first one found in the U.S. was near Atlanta, and it’s definitely invasive. It spread to five other states in just four years.

Invasive botanical species are displacing native species in many places in North America.. Invasive non-native insects are quickly bringing about extinction of some native species. If one believes there is an order to nature and the individual continental ecosystems have evolved to be the best use of a place, then invasive non-native is a bad thing. As a forester this is what I experience in the oak, hickory, hemlock, Appalachian forest type. Emerald Ash borer, long horned Asian beetle and hemlock wooly adelgid are glaring examples of negative impact through what seems to be inevitable extinction of many native species. They are similar in impact on our forested ecosystem as the Chestnut blight that eradicated the most productive largest deciduous tree in North America, the American Chestnut.

I think the bittersweet Gene writes about is oriental not European and it is so aggressive that when a clear cut is created in some areas, the native forest species of dominants (trees) cannot regenerate and we have a land surface covered in aggressive vines and not trees. It is so fast growing that it will pull a tulip poplar sapling over from the top down and it dies. It produces bright orange seeds that are spread by birds in a fertilizer coated randomly deposited method – very rapidly on the time line of individual ecosystem evolving. There is another species of grass ,microsezium (sp) commonly called Japanese Ladder grass that takes over the surface of the ground and a tree seedling can’t grow through it. Chiggers love it though, so if you don’t like trees and like chiggers it could be a good thing.

I think one of the most important aspects of non-native invasive species in the forested conditions is that they are all disturbance dependent, meaning – human activity mostly removing native species and exposing bare soil. This is a consideration that hasn’t had adequate recent research to determine how non native invasive species respond to various silvicultural treatments of the forests. This is one of the reasons I submit that a good place to start in active attempts of man to age the forests is low impact harvesting by using the ultimate low impact overland technique of animal powered extraction to accomplish “worst first” single tree selection. This is what I call Restorative Forestry. Since we have mounting evidence of the decline of the quality of our forested conditions, I don’t accept any definition of conventional forestry as being sustainable. I don’t understand how we can sustain a decline. I submit that in order to have a chance of being sustainable forestry must be restorative. I don’t want to debate what is sustainable but would prefer to debate what is restorative.

I have to add that contrary to what one poster said Corn is a native plant and the largest crop in North America. It may be a long ways removed from the maize that was part of the sustenance diet of Native Americans, but it is a native plant and the largest crop we grow. I happen to grow non gmo open pollinated corn for my own animal feed, corn meal and seed corn. Our corn is grown without chemical fertilizer, herbicides or pesticides. It is grown as a part of good sound farming practices including crop rotation, strip contours and planting by sign.

I do worry about the impact of non native invasive species. I battle them daily – pull oriental bittersweet, garlic mustard, multi-flora rose in every forest I work in. Atlanthus or tree of heaven are invasive and some evidence suggest they are the host of the non native invasive stink bug that is in our homes and gardens everywhere in the central Appalachians. A few years ago it was oriental ladybugs coming into homes, which I may have contributed to by buying bugs from a company called “beneficial bio systems” that sold insects that turned out to be non native… As the great philosopher/cartoon character pogo said – “we have discovered the enemy, and it is us”.

Science is working to battle many of these non native invasive species. But I am not one to have great faith in technology or science to solve the basic ignorance of human kind. Some lessons are late to be learned and hard to remedy. I do trust the order of nature as a model for mimicking as a longer standing example of the gift of creation.

Thanks to Gene again for writing thought provoking words and bringing light to issues common to all of us.

Jason Rutledge

Multiflora Rose

Invasive is different than merely non-native. Invasive is a non-native that displaces native fauna or flora. Honey bees may not be native, but they don’t threaten or displace native species and in fact are very beneficial. Invasive plants like Scotch Broom on the other hand, quickly take over any open land and put out thousands of seeds per plant that remain viable for decades. I watched a 35 acre field become choked with broom and Armenian blackberry in only a couple of years. It is a constant battle to keep my land clear.

Having grown up in So Cal where there are large tracts of eucalyptus, I can tell you that most of them did not come from Mexico, but were imported from Australia. There are very few native eucalypts in the New World, and those are not really found in abundance, having few natural predators.

While I like the smell of some of them, most of them smell like cat pee to me, and I’d just as soon they were gone… Now I live in a juniper forest, and it smells like cat pee when it rains here, too. Can’t win.

The problem with the established stands of eucalyptus is that they are most of what’s holding the soil together where they are. Nothing grows under them (or very few things), and certainly nothing that will keep the soil stable. If you remove them, you’ll have to stabilize square miles of soil – and that’s just not practical.

I had a feeling that previous discussion about introducing non-native species was going to spark a column ! Based on my background in quality improvement, I’m well aware that all systems change/deteriorate over time. Of course, in the context of ecosystems, “over time” often means over millennia. Take the star thistle, the scourge of arid areas in our state of California. I suspect that several million years from now, something will have evolved that can eat it or a bug will mutate and be able to give it a nasty disease. in the meantime, I have to contend with it in those areas where I can’t water — as a very drought-resistant plant, it just can’t handle irrigation, but drowns and dies. To offset the irritation, however, it does provide a great source of food for the honeybees, and star thistle honey is yummy stuff. But for a dryland farmer, star thistle in her fields or pastures can be an unmitigated disaster. Heavy concentrations of goats will eat the stuff; but with thousands and thousand of acres already infested, the only way I could see that being economically viable would be to get all Americans to stop eating beef, pork and lamb in favor of goat meat. I suspect the various meat industries would have some concerns about that idea. Fix one problem, create another…

    Nothing wrong with goat, after all it tastes like a low fat lamb and is far healthier

      We butchered two 6-month-old Nubian/LaMancha wethers, still nursing, a couple months ago and they were delicious. Not a lot of meat, but at a leisurely pace we were done in about four hours.

      Better yet Whitetail Deer great low fat meat and they thrive on “Invasive Species” like Russian Olive,Honeysuckle,Autumn Olive and most anything else one can think of to plant.
      Most any plant or animal can be a plus in the right situation or a negative in the wrong situation the challenge is to find a useful purpose for things that grow easily and with little cost.Stinkbugs are a perfect example my Muscovys love them.Personally I love a nice stand of thistles as they support all sorts of wildlife bees,birds,butterflies plus they grow in K deficient land and bring up K to the surface of the soil according to Charles Walters.

      The young goat meat I’ve eaten — I held back for a long time– is delicious, but I would describe it as much, much milder than any lamb I’ve ever eaten. Based on how closely related sheep and goats are I might have thought the meat would be similar, but lamb is about the last thing I’d think to compare goat meat to. My experience with goat meat is still pretty limited, though.

Hey, I like Canada thistle. My goats eat it with a lot more relish than grass and the songbirds like the seed. Plus it packs a lot of nutrients. One man’s invasive weed is another’s useful pasture plant!

Native and non-native is a human invention or concept if you will, witness the recent videos on internet of assertions that white European folks “invaded ” North America way back in the ice age via boat voyages and then met the “Native Americans” who also allegedly originated from Asia. Then, so the story goes they interbred and some of the European genes may be seen in certain “tribes” of Native Americans today as per genetic analysis. And let us not forget that Native humans often entered into conflict with other tribes of humans throughout human existence wherein “We” killed and replaced or interbred with “They”. SO the question remains who or what is then truly native.

Also, as was discussed on this forum some time back :”Invasive” European ” earthworms came to this continent probably hidden in ship’s ballast and commenced doing what they excel at: recycling organic material and minerals. but allegedly to the benefit of agricultural soils and pastures and allegedly (in contrast) to the detriment of hardwood forest floors. because they allegedly recycle fallen leaf material too quickly.

I’m told that certain stands of Oregon White Oak (Quercus garryana) in my region, that are isolated from other stands by many miles were most likely the result of human plantings of acorns way back when. Would these isolated oak stands then be considered as native or not? It all gets quickly confusing. I once had a :”Native American youngster, who also had some European blood he was ignorant of tell me to : “Go Home White Man.” I then wondered just where would that : “Home” be,given that my ancestry is a mixture of European and Native American genes?

The point being that the earth itself is constantly changing via continental drift and other means or as the scientist would say it’s: ” dynamic”; so it should be no surprise that the organisms on the earth are also dynamic. I suspect that the best we can do is accept that and try to husband the resources, including organisms native and non-native, invasive or neutral, which are under our stewardship to contribute to the most good and the least harm. But that would lead to the discussion: “What is good and what is harm?”

Si in response, I’ll continue to enjoy the fruits of the garden and orchard , the flowers and animals both “native” and “Invasive”, or in between. For an example some say that the blue elderberry bush in my yard is native, other sources indicate it is an invasive import. All I know is that “elk” and deer really like to eat the leaves and stems, as do “Native” birds the berries. My non-native goats also enjoy the foliage and my non-native chickens will fly into the branches to eat the berries So I’m “rescuing” what ripe berries I can from the birds to mix with my domestic non-native grapes to make jams and jellies. Maybe being invaded isn’t necessarily a bad thing.

And then there’s the invasive plants that travel south to north with global warming. I guess we can’t call them migratory since they don’t travel back before winter… 😉

Invasive maples? You should be so lucky, there was an item this morning on NPR about the 100-200 year old maples that are being poached here in WA for cellos and Gibson guitars.

Invasive is different from non-native. What diet would we have without all the non-native plants and livestock? Turkey and other game, small berries, black walnuts and pecans with a dash of maple syrup, wild rice, and that’s about it. I don’t think there are any major grain or vegetable native to the U.S.

You just are terrific. Love your writing and your timing with your topics.

Thanks, Natalie

*From:* The Contrary Farmer [] *Sent:* Wednesday, September 25, 2013 11:25 AM *To:* *Subject:* [New post] Good Invasive/Bad Invasive

Dave Smith posted: ” From GENE LOGSDON Among the many handwringing issues popular with todays paranoid society is the issue of invasive plants and animals. Not to mention invasive human beings. The matter came to a head in California recently over a kind of eucalyptus”

After the glaciers left the northern half of N. America there was mostly just water and gravel. All the plants have since come from somewhere else. Wind, birds and land animals brought in seed and continue to do so even today. Ecosystems change. Species move.

What is a garden farmer supposed to do?… At least for ornamental plantings stick with natives or if you must plant some non-native remember the consequence to native fauna (a la Doug Tallamy’s book Bringing Nature Home) and at least plant something that doesn’t out-compete natives when the seed spreads to your neighbor’s lands (think Ginko not Tree of Heaven). And if you’re going to plant something like Autumn Olive to eat the fruit then take care to actually do so (net it from birds, etc.). The benefits to things like Callery Pears, burning bush, barberry, mimosa just do not exceed their cost – especially when you think of your neighbors or public natural areas that have to spend money controlling infestations.

I could be wrong about this, but back when I lived in California the various forest services and even the fire department in Redwood City where I volunteered were all concerned about the Eucalyptus globulus, which is a very large and fast growing tree imported from Australia. Those who originally planted thousands of acres in Eucalyptus groves were hoping to use it for timber, but some missing essential nutrient in the California soils make the tree trunks all twisty instead of straight-grained.

If you are anywhere near a grove you can smell that wonderful Eucalyptus scent, which can really travel downwind. Because of the oils and the shredding bark they tend to go up right quick, like torches, when they catch fire. Some species use up an awful lot of water, so sometimes they are planted in swampy areas for drainage and mosquito control. And I’m almost positive the huge Oakland fires in the early 90s involved the Australian trees. Some folks had been warning about that for years, complaining about how quickly a very flammable biomass built up on the forest floor around those trees.

We used to collect the nuts, or seed pods or whatever they were – those little round kind of acorn-shaped bits – thread them on a string and wear them as ankle bracelets ourselves and put them next to the collar on the necks of dogs and cats as a flea repellant. Seemed to work pretty well.

There are a few other varieties of Eucalyptus imports from Australia too, such as Eucalyptus polyanthemos and Eucalyptus pulverulenta. I’ve never heard of any of them being from Mexico, but I suppose it’s possible.

The Missouri Department of Conservation has put out a couple of books on tree identification, shrub/bush & vine identification, pond plants, etc., which are incredibly useful and interesting. But what I find confusing, even odd, is that for each species there is a corresponding state map that shows which specific counties that plant is “native” to, based, I think, on where it was found X number of years ago.

For example (and I’m going off of memory; I don’t have a copy in front of me), for one species of wild blackberry County A is completely surrounded by counties where that particular species is “native,” but for some reason that species is not native to County A. First off, I find that a bit hard to believe. And second, that species of wild blackberry might be growing all over County A today, but because it wasn’t (apparently) growing there X number of years ago it is considered “nonnative” (but not necessarily “invasive).

I guess my point is that the term “native” seems to be, at least in part, based on some arbitrary point in time; really it’s an accident of history. Populations are dynamic, and species are always moving, sometimes being unwisely and hastily introduced, but sometimes moving in completely “natural” (whatever that means) ways. I have no interest in the politics of the immigration issue, but I find it laughable that white people who came freely from Europe centuries ago think it their right to deny that same passage to modern non-whites from Latin America. (And I’m white as white can be, for what it’s worth.) Somehow we’re the new “native” and they’re “invasive.” (Those redskins? An interesting bit of American history, perhaps, but nothing more.)

I also might posit that “invasive” species might not deserve all the bad rap. I’ve got more multiflora rose on my 25 acres than I’d care to–a lot more–but last year I noticed a usefulness I’ve not seen mentioned elsewhere. On my way out to the garden I had to pass through a gate, and around the post where the gate was hung was a huge, overgrown multiflora rose bush (since cut down). One day in early summer I passed through the gate and the bush started buzzing, full of Japanese beetles. The bugs, it seemed, were feasting on the rose and couldn’t care less about what was in the garden. Stayed there all summer. That alone is worth the keeping a few scattered bushes, in my opinion.

    That sort of range map is usually based on documented occurrences of the species, generally herbarium specimens. If it’s not shown from a particular county, but all surrounding counties have it, it usually means that it was simply never collected and documented from that county.

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