Invasive Species in a nutshell

[TheLorax]

Lots of talk in many threads about invasive species and seems as if there are a lot of gardeners trying to make sense of all the bad press some plants are getting lately who are interested in learning more about them. The below is something I use when working with younger groups of children. Most of them have read 'The Lorax' but many aren't familiar with 'On Beyond Zebra' so I read it to them in its entirety before we move forward.

We all know and love Dr. Seuss. In addition to 'The Lorax', Dr. Seuss wrote another book I'd like to mention. Have you ever read 'On Beyond Zebra'? It's about "the rest of the alphabet" A very young child, Conrad Cornelius O'Donnel O'Dell, is very proud that he has learned the entire alphabet from A to Z. His friend, though, draws another letter and says

In the places I go there are things that I see
That I never could spell if I stopped with the Z.
I'm telling you this 'cause you're one of my friends.
My alphabet starts where your alphabet ends!"
He then proceeds to describe the alphabet on beyond Zebra.
One of his special letters is NUH.
"And NUH is the letter I use to spell Nutches
Who live in small caves, known as Nitches, for hutches.
These Nutches have troubles, the biggest of which is
The fact there are many more Nutches than Nitches.
Each Nutch in a Nitch knows that some other Nutch
Would like to move into his Nitch very much.
So each Nutch in a Nitch has to watch that small Nitch
Or Nutches who haven't got Nitches will snitch.

The invasive species problem we are all facing in a nutshell. Every native species is a Nutch. Non native and highly invasive plants such as Albizia julibrissin (Tree of Heaven); Pueraria montana var. lobata (Kudzu), Passer domesticus (English House Sparrow), or Rattus norvegicus (Norway Rat); don't have a Nitch (niche) of their own here on North America. The only way they can get one is to snitch it.

[opabinia51]

Invasive species are not necessarily always introduced species . Some native species are highly invasive. This is an evolutionary strategy that some plants use to survive and outcompete other plants.

Of course, not all plants are invasive in every environment. Morning glory is highly invasive where I live but, is not in other parts of the globe. Ivy is horribly invasive around my area but, in parts of North America it is not. I know that in Canada and the U.S. each Province and State has it's own invasive list of plants that are invasive in that area. When planting a garden it is wise to look up your invasive species list before rushing out and buying plants.

And if you do plan on planting an invasive species (I grow mint and have groldenrod in my garden which are both highly invasive species) watch them and keep contrl of them in a safe and environmentally safe manner.



Furthermore, a little warning with mint; if you grow it the roots will spread out in the soil, dig the roots up each year. Mint will even take over you lawn if you are not careful.


Also, I think that invasive species discussions should happen in each particular forum that a certain invasive would pertain to. This way we can stay on the ball and people doing that particular type of gardening can be informed about the invasives.

[NEWisc]

Opabinia51 brings to light a very important point about invasive species - the definition of invasive. To most gardeners invasive plants are plants that go where you don't want them. Where they are from (origin) is not an issue.

To the someone looking at plants from an environmental perspective, an invasive plant is a plant that is from a different origin, it has invaded an area that it would not occupy as a result of any natural process.

Naturalists usually avoid this misunderstanding by using the term "ecologically invasive", which is a much more accurate way to describe the plant being discussed. They would also describe what the gardener calls "invasive" as an "aggressive" plant if it is a species native to the area being discussed; since a native plant can't "invade" an area where it is from.

Naturalists, being human like everyone else, look for shortcuts; so the ecologically invasive term often gets shortened to invasive. Let the confusion begin ...

A couple of thoughts on sorting out the confusion:

When states and other governments publish lists of invasive plants they are talking about ecologically invasive (non-native) plants.

When environmental organizations publish lists and fact sheets they are also talking about ecologically invasive (non-native) plants.

Ecologically invasive plants harm the ecosystem; native plants support the ecosystem.

When you visit any gardening site other than the ecologically enlightened HelpfulGardener site they are usually just talking about a plant that goes where you might not want it.

Note: I've used plants in my discussion, but it's applicable to any kind of invasive species.

Edited for a grammatical correction.

[MaineDesigner]

Good post, NEWisc! I agree with everything you wrote but this touches on my opposition to broad definitions of "native". When I use the term native I mean native within, at most, a hundred mile radius. I think the definition of native to include every species that existed in pre-colonial North America to be ridiculous. If a plant that has no naturally occurring populations for a thousand miles is introduced I fail to see how that plant is in any meaningful sense "native". If we want to push that I would even question calling regional variations "native" once they are moved into the range of another regional variant.
I can't think of a good example off hand but it does seem possible that plants native to portions of North America could be in some sense ecologically invasive if moved 1,500 mile to a completely different North American biome.

I don't use ecologically invasive plants in my design practice because I feel some sense of responsibility to and respect for the environment. I also don't use many aggressive plants, or those with substantial disease or insect issues or that simply don't play well with others, whether they are native or not because they don't fit my design objectives. That is, of course, a completely different issue.

[NEWisc]

Yes, I completely agree - the definition of "native" is another area where confusion (and a lot of misinformation) exists. We're kind of expanding TheLorax's nutshell here, but I don't think TheLorax will mind.

I think a good example of what you were pointing out is the American White Waterlily (Nymphaea odorata). It is native to much of the Eastern U.S., but classified as a noxious weed in Washington State where it is not native:
https://www.ecy.wa.gov/programs/wq/plants/weeds/lily.html
Washington State does not want this plant disrupting the natural flora and fauna communities that have evolved there.

The pre-colonial North American time reference is often used in definitions of native plants because it is an easy way to eliminate all of the plants that were introduced by the European settlers. But as you point out it does not work if that is the only criteria that is used.

Native plants are more accurately determined by ecosystem boundaries and the natural plant communities that exist in that ecosystem. but that can involve some complex criteria and analysis. Those boundaries often don't match the geographical and political boundaries that we humans are most comfortable with.

That being said, I do think there is some value to seeking an easily understood yet reasonably accurate [useful] definition for a native plant. The best solution that I can think of right now are the state published lists of plants native to that state. I know, I know, some states have wildly different ecosystems within their boundaries but at least it's easy and the list is going to be regionally accurate. Most of these lists are developed from state herbarium data and it's been reviewed by botanists familiar with the plants in their region.

"I don't use ecologically invasive plants in my design practice because I feel some sense of responsibility to and respect for the environment." If only we could get all of the people in your profession to adopt that wonderfully environmentally friendly philosophy.

[MaineDesigner]

"I don't use ecologically invasive plants because in my design practice because I feel some sense of responsibility to and respect for the environment."

Doh! I really have to stop posting in the early AM without enough tea or coffee to get my synapses firing. I actually can write a coherent sentence when I'm fully awake - at least occasionally.

[TheLorax]

Ah, very good points regarding how we humans chose to define native as our own personal styles of gardening emerge and evolve over time. NEWisc and MaineDesigner, you are truly invaluable contributors here at THG.

Best for me to do as others are doing. Follow the Feds definition of native-
https://www.osmre.gov/veg2.htm

A native plant species is one that occurs naturally in a particular region, state, ecosystem, and habitat without direct or indirect human actions.

I've posted these links before but felt it best to post them again-
https://www.fhwa.dot.gov/environment/rdsduse/rdsduse5.htm
https://www.audubon.org/bird/at_home/PlantNativeSpecies.html

For my own personal style of gardening, to the above I would add the cut-off in the time line as being prior to European colonization. Yes, I realize there are those who go back considerably farther.

If one uses the above definition provided by the Feds, one will find that invasives are almost always an introduced species.

To really throw a fly in the ointment, please consider the following-

No plant is an island: each exists in a context and community of trees and toads, rocks and rotifers, birds and bugs. Like human communities, this network of individual needs is supported by complex communication and mutualisms that we hardly understand.
-William Cullina

I like the idea of using State's lists but...
let's not forget terrestrial and aquatic ecoregions of North America and our individual micro regions.
Basic overview here-
https://www.cas.vanderbilt.edu/bioimages/ecoframe-map.htm
We North Americans are all sharing the same beaker.

https://www.cec.org/files/PDF/BIODIVERSITY/eco-eng_EN.pdf

In North America, we share vital natural resources, including air, oceans and rivers, mountains and forests. Together, these natural resources are the basis of a rich network of ecosystems, which sustain our livelihoods and well-being. If they are to continue being a source of future life and prosperity, these resources must be protected. This stewardship of the North American environment is a responsibility shared by Canada, Mexico and the United States.

Although it is true that when Dr. Suess wrote his book we didn't know nearly as much as what we know today, we simply must give the man credit for spotting that something was seriously amiss. To this I must add that I see it to be virtually impossible to garden conscientiously and responsibly these days without expanding the nutshell! After all, our land was irreversibly altered to enable these subdivisions to rise up out of the dirt so as humans we can only do our best. Acting as individuals, each of us can be a small but meaningful force to improve things. In the collective, we can be a tremendous force. The very power we have to damage the environment is what compels us to act as its stewards. Please don't abdicate this responsibility because you think it's hopeless- It's not. Or because you think you can't make a difference- You can. Or because you think the world will survive without our stewardship- It may, but it will be a poorer and meaner place. The issue of preserving biodiversity is extremely complex but there are some simple tools we can use to preserve what we can. One is to find out what terrestrial and aquatic-dependent species are native to our areas and enhance those populations in and around our properties as opposed to introducing new ones.

Expanding upon this concept that something is seriously amiss, I conscientiously choose not to knowingly plant any species that is identified as being a noxious weed, an invasive species, or as being a non-native species that has naturalized. I know my lifestyle well enough to realize that we take off quite a bit. I could also die on the road tomorrow and who would be here to contain and deadhead any species purposefully planted that isn't exactly environmentally responsible let alone even be able to identify which ones should be contained and deadheaded should I ever be removed from the equation? Good question and one we should all be doing a little bit of soul searching on to ask ourselves. I don't want to see the world that some look forward to with great mirth where the wonderfully diverse native flora and fauna of various ecoregions is replaced by a few ubiquitous "super-fit" species. Where English house sparrows and European starlings, Carp and Tilapia, Cuban treefrogs and cats rule a world covered with Kudzu, Saltcedar, and water hyacinth.

Although I agree invasive species should continue to be discussed in each particular forum, just as roses and herbs and vegetables are.... Invasive Species, should be deserving of their own forum. Might as well get in a plug for Sustainable Practices too as that's most definitely deserving of its own forum at a "green site" also.

The best time to begin managing, controlling, and eradicating noxious weeds, invasive species, and non-native species that are naturalizing was 50 years ago... the next best time is right now.

And now it is time for me to take a break from THG in favor of going back to the ListServe.

[ahughes798]

I completely don't understand why there is ANY confusion about what is native, and what is a non-native invasive.

Native = been here before the europeans.

Some native plants are aggressive...Solidago canadensis, Asclepias syriaca, and many more....but they are aggressive on disturbed ground. They aren't a problem on virgin prairie remnants because they are out-competed.

There are over 100 species of goldenrod in the US, and not all of them are aggressive.

[TheLorax]

I'll run with this definition of invasive-
https://www.invasivespeciesinfo.gov/whatis.shtml

An "invasive species" is defined as a species that is

1) non-native (or alien) to the ecosystem under consideration and

2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health. (Executive Order 13112).

Invasive species can be plants, animals, and other organisms (e.g., microbes). Human actions are the primary means of invasive species introductions.

Invasive Species Definition Clarification and Guidance White Paper (PDF | 104 KB)
Submitted by the Definitions Subcommittee of the Invasive Species Advisory Committee (ISAC)
Approved by ISAC Apr 27, 2006

https://www.invasivespeciesinfo.gov/docs/council/isacdef.pdf

Invasive Alien Species Concepts, Terms and Context (IAS-CTC)
CAB International.

https://www.cabi.org/ias_ctc.asp?Heading=Terms

While there have been numerous attempts to clarify the term invasive species, there continues to be uncertainty concerning the use and perceived meaning of the term, and consequently over the prospective scope of actions proposed in the NISMP.

Admittedly, there are issues with how many choose to define invasive but the above works well for me.

[ahughes798]

There are many exotic species that are not invasive. Now.

According to a book I'm reading by Douglas Tallamy, "Bringing Nature Home", there can be a considerable lag time between the time a species is introduced and the time it becomes invasive. Like 80 YEARS.

I'm torn about exotics that aren't native. I have german bearded irises, and a tree peony. Will they become invasive many years hence? Yellow flag iris is an invasive species, after all. Maybe it wasn't, at one time?

Mr. Tallamy makes a really good case for planting things that are native to your 100 mile radius.

I am a "native east of the Mississippi river" gal...but I'm starting to re-think my position.

[TheLorax]

That book is one that is hard to put down isn't it.

I feel for you based on these comments, "There are many exotic species that are not invasive. Now". I'm finding myself increasingly striving for locally native plants (25-50 mile radius for me) as a personal goal for the natural areas of my property. Something I've recently begun doing is adding eastern NA natives to enable me to show small groups that visit here that a Fothergilla tucked in nice and close to my home is every bit as beautiful if not more so than a Burning Bush. Gotta work with what's out there and readily available.

Regarding our German Bearded Iris... yes, I believe we will learn that they are a problem child. Regarding the tree peony, don't know. But here's one for you, how about my Physocarpus capitatus?