That's probably true that sub par seedlings would not survive, but if you flood the area with "sub par" pollen, it's likely that a majority of the seedlings would be sub par, and thereby most of the seedlings would not survive.

Ninebark is a native, but around here all of them have shades of purple foliage. It's the diablo effect.

People are anxious to breed and reintroduce native blight resistant chestnuts, but with all the Chinese and Chinese hybrids around, even a grove of native chestnuts is likely to produce Chinese hybrid seedlings.

Planting natives is still good for your ecosystem, but evolution won't stop and nearly everything you plant, exotic, native or hybrid will effect the local gene pool..... Unless it's plastic of course.

Many property owners would probably prefer that insects not chew on their plants, in that case they can use Lilacs or hydrangeas or non-natives which are not invasive. I don't mind a little chewing on my plants, in fact I think it's cool because those caterpillars might become baby bird food or maybe an interesting moth. This past spring I did have to spray some BT on the Corylus americana, american hazelnut, because it was completely defoliated last year and I didn't want that to happen for a 2nd year.

I'm purposely trying to affect the local gene pool in a direction towards more native species. The understory level of the woodlands around here consists of mostly non-native invasives. Japanese shrub honeysuckle dominates, with burning bush, buckthorns, barberry, rosa multiflora, norway maple, privet, and others chiming in.

I've removed tons of invasives and planted many native shrub/understory tree seedlings in the yard in 2007-08. Now most are old enough to go to seed, and hopefully the birds are helping to disperse seeds for natives like Elderberry, grey and alternate leaf dogwood, serviceberry, and viburnum.

I wonder if a non native species is capable of becoming a native species over time? Isolation often leads to the formation of new species. For example if tree of heaven is left wild in this country long enough (couple hundred/thousand years) and its genes are isolated from the asian population would it not become a new species and find a niche in the ecosystem?

The issue is further complicated when we consider the issue of time. Native when? Before the breakup of the Pangeaan supercontinent or its forerunners? Before or after the glaciers which covered much of the planet?

We need to be careful about the introduction of seriously invasive species such as Norway maple, bittersweet and barberry, but there's no reason for gardeners to deprive themselves of the many beautiful plants from Asia, Europe, or South America in places they can be grown. "Native" species are not botanically or morally superior.

Likewise, why ignore beautiful, easy-to-grow natives? Eastern north america has a staggering array of natives - Shade trees, flowering trees, shrubs, ground covers, vines... While I do use some exotics (My border would be lost without zinnias and cosmos), I've found that the plants I prefer happen to be native. Also, one of my "gardens" is along a floodplain near natural woodlands. I figured it probably would be more sensible to stick to natives when gardening this close to larger natural areas.

would it not become a new species and find a niche in the ecosystem?

I don't even know the definition of how that would come to be. I suspect it would be more like hundreds of thousands of years (100,000+ years). In order to find a niche, it would have to support life - insects, I think. That is the first step to being a valid part of the system.

I am not convinced about the argument FOR natives, to be honest. In most ecosystems (and complex systems in general), a reduced genetic and species diversity leads to a greater vulnerability of the system to large shocks. I do think that, while it is probably a good idea to avoid spreading invasives (defined as plants that are placed where they have no competitor), I do think introducing new plants, in the long run, will be a good thing.

There is also the other perspective that, short of completely shutting off travel and commerce, non-native will eventually find their way into our gardens. There is no such thing as perfect control of a border. It will just delay the inevitable.

I think there is far more danger in planting monocultures throughout half a country, and in being too reliant on breeding (you can only breed for the traits you can detect and you desire... not necessarily those that are necessary for long term survival or for ecosystem balance).

On the other hand, I'll be the first to plant cultivars in my garden, if I need. :-)

"Its interesting that the UK has such a small amount of native species. It must be because of its long history of human habitation. "

greenthumbzdude - it's due to the last Ice Age, about 25,000 years ago. Most of the species we now consider to be Britain's native trees and shrubs were confined to southern Europe. Between 10,000 and 5,000 years ago they recolonised and, since we are an island, it took a long time and they still numbered fewer than the rest of Europe. But the humans certainly haven't helped.

I think there is far more danger in planting monocultures throughout half a country

Such as lawns (turf grass)?

It's a matter of science. Simply put: vegetation converts sunlight to plant material. Insects consume plant material. Other things consume insects (birds, larger insects, reptiles, some mammals). A chain of related activities. Pretty simple right? Reduce the number of plants and you reduce the insect population which reduces the populations of all those that eat those insects.

Insects should be able to eat any plants. But they can't. Most of them have evolved over thousands of years to eat certain ones. You can't just bring in plants that they didn't evolve with and expect them to eat those. They don't. They reduce their population instead.

So when you shift the plant material from predominately native to exotic, you reduce the insect population and everything that depended on it. And lawns, by the way, are a big reduction.

There are a lot of good posts here. One thing I deal with is what I call the "Natives-only Nazis". That is, while I have been fascinated by plant communities since late childhood, there's now a movement afoot which would seek to extirpate any plant that that person believes to not be native. In so doing, a great many good and useful plants would be lost. And for what? Probably some other more aggressive non-native would just fill the gap.

More importantly still, native species are in serious decline in many areas. More often than not, this is happening due to some imported pest or pathogen. In my view, we are going to HAVE TO incorporate some non-native species into our forests and wild lands to plug these gaps.

But....and there's always a but...it is equally crucial that we retain those islands of intact, or even relatively intact, natural, native plant communities. This then becomes political. Are we so "pro-growth" that the elimination of yet another stand of trees and their accompanying understory flora and fauna in order to build another strip mall with it's bank branch, dry cleaners, and convenience store is a worthwhile tradeoff? You know...."create jobs".

And I posit too that we are now at the turning point where we truly can shut the door on nature. We have the means. We have the political climate. It's already happening.

+oM

"greenthumbzdude - it's due to the last Ice Age, about 25,000 years ago. Most of the species we now consider to be Britain's native trees and shrubs were confined to southern Europe. Between 10,000 and 5,000 years ago they recolonised and, since we are an island, it took a long time and they still numbered fewer than the rest of Europe. But the humans certainly haven't helped."

Actually they did help. Chestnut and a few other useful trees was brouht to the UK by the romans, as far as I understand. Some people even think that beech had human help.

I have read Bringing Nature Home by Doug Tallamy and basically it provides scientific evidence that natives are better at supporting wildlife. A long term study was done and found that 90% of our native songbirds (scarlet tanager,eastern bluebird,red eyed vireo) all rely on the Lepidoptera (moths and butterflies)to feed their young.Since the Lepidoptera are host specific and only feed on species they have co-evolved with, any destruction of those has a large impact on the entire food chain.Right now there is a 68% decline in the songbird population. So I think that if we want to continue having these unique songbirds and other types of wildlife we need to consider natives as an option; maybe even choosing them over non natives. Since humans tend to procrastinate and wait to the last minute to solve their problems, I really hope that the future inhabitants of this planet dont end up having to clone all the species lost to our own selfishness.

Not at all disagreeing with you Green, but another big factor in the demise of our song birds is the loss of habitat in their winter homes in Central and South America. Sad to see that the adaptations of these species-to actually travel thousands of miles every year to better allow their survival-is now also helping to seal their fate.

+oM

there's now a movement afoot which would seek to extirpate any plant that that person believes to not be native.

I'm pretty involved in native plant groups in several states and I have not heard of this. Do you have any links to articles or websites about it? I personally do not support such an approach, I don't think it's necessary. Having a reasonable amount of non-natives is not an issue for me.

esh. I don't think there is anything simple about ecosystems.

I just think that, regardless on whether natives or non-natives are good, the war on "non-natives" reminds me a lot of the war on piracy. It is just a manifestation of new capabilities (in the case of non-natives, due to fast and global travel, and extensive trade) and there is nothing that you can do to fully prevent it from happening unless you remove that capability. If we would have stuck to natives we would not have tomatoes in Europe, or potatoes.

Furthermore, there is no such thing as a "native" plant. I don't even think there is a good definition for it. All plants developed and migrated due to changes in climate. The only thing that changed is the pace of the changes. The whole debate "who was there first" makes very little sense to me. Nature always changes and knows how to deal with change much better than we do. It is us humans that find that change unnerving.

I believe that, in many cases, this "native nazism" has more to do with the fact that it feels really clean and pure to "stick with the natives". I believe the more we interbreed, crossbreed, and mix stuff up, the better off we are going to be.

Um...both?

It does bother me that the definition of native is rather vague. I think it should include the idea of a niche (ecological role). All the species that are considered native (at least on the east coast) have a role in the ecosystem by supporting insects, providing fruit, shelter, ect. A non native might provide shelter or fruit but it will never support a healthy insect population because of the way in which coevolution works. Native plants provide the foundation for a healthy ecosystem. All biotic factors work together to create a single living community complete with checks and balances (predator/prey relationships).When non natives are added it interupts the flow in the ecosystem for some time until those species find their own niche. I can almost guarentee you that all the non native invasives in this country will become native eventually. It going to take a long,long time though (think thousands of years). However this could also mean extinction for some of the native species that we have grown fond of.So I think at this point its a matter of wanting to preserve the working ecosystems we currently have or choosing to alter them in a way that suits our own needs.

I really don't see or hear much evidence of "native nazism" these days. I understand there was some talk of it 20 years ago perhaps, but everyone I work with for the last 12 years is not that way. People realize that non-natives have values whether it be for food or aesthetic reasons.

The push now is to understand that the are scientific reasons to keep a diverse amount of native plants in the landscape (and to preserve native habitat where we can). Homeowners can make a difference by choosing more natives than exotics, by reducing excessive amounts of lawn and by working together to create mini-corridors of habitat in their connected spaces.

It's not a "feel good" issue. It's science.

By the way, for those considering the definition of "native", you may find this post useful.

Here is a link that might be useful: What is native? What is not? When does it matter?

Esh, I have no disagreement with you, or with the folks you mention. Nor did I mean to imply that there is an organized movement to banish non-native plants. It's more the beginners-people that just woke up to the fact that there are some great native plants(!) that can sometimes go overboard. Thing is, they sometimes are the leaders of some smallish volunteer group or what have you.

I don't think there's a hair's thickness of difference between your approach and mine.

+oM

Yes, the excitement of new discoveries often gets tempered over time by reality. I agree we probably are very similar, Tom.

"A non native might provide shelter or fruit but it will never support a healthy insect population because of the way in which coevolution works."

I get your point, but if you went to a nursery and set up 2 lots side-by-side with very similar looking plants covering an array of sizes, colors, etc..., and put a sign in front of one saying 'Plants bugs will eat' and in front of the other saying 'Plants bugs won't eat'...that nursery would sell a lot more plants from the 2'nd lot.

Richard.

An item not addressed by anyone yet is the habit of planting commercially available natives vs planting "wild" natives.
A side variant of this is planting clones vs seed-produced trees. Both of these habits will lead to a shrinking of the gene pool for species if carried out long enough. But most likely this is such a small part of the population that its effect will be miniscule.

1cadem, thing is, once certain invasive plants move into a woods, diversity is ultimately reduced. In the case of what common buckthorn is able to do around these parts, it truly appears hell-bent on becoming the only species left.

I truly enjoy the effect had by incorporating certain non-native trees into a primarily all-native setting. Thus, my tendency to drop Norway spruce into my woods here and there. I do not believe these will ever become problematic though. And if I'm completely honest, I would actually like to see them ultimately become naturalized. Doesn't happen a lot, but it can happen to a limited extent. A strictly purist viewpoint would not allow for this. But the way I see it, there are very few if any native white spruce in my woods, so it's a stretch to say that these NS are crowding out the closest native equivalent. They're just not. Maybe crowding out some other genera but it's hard for me to feel any guilt about that either because I'm gradually increasing the total area for those plant species to colonize as well.

Obviously, for me it's all about what species we're talking about. If box elder-a native tree-started hogging a lot of room in my woods, the saw would come out in a hurry! And if the hybrid larch I've got planted nearby should ever mix genes with the native tamaracks, also in my woods-not saying they will, but if-I'm not sure that would be a bad thing either. I believe that we humans can actually increase the overall richness/diversity of a given piece of land. Just depends on what plant(s) we're talking about.

+oM

Yeah, it is scary to hear that bugs will eat your plants. But in fact they only eat a small portion usually (occasionally there will be overpopulation and they will eat a lot but that is not the norm). It is definitely a tricky point to convey in a positive manner.

once certain invasive plants move into a woods, diversity is ultimately reduced. In the case of what common buckthorn is able to do around these parts, it truly appears hell-bent on becoming the only species left.

I agree with this, extremely vigorous and adaptable exotics like glossy buckthorn will push out more fragile (and maybe even the aggressive) native species below the canopy level, which will result in fewer total species.

Re: cultivars, I think it could be a problem if they are used exclusively (which they probably are for the majority of landscaping). If a threat to a species arose, and a cultivar doesn't have resistance, then it could be wiped out. Whereas if you have the genetic diversity of hundreds or thousands or millions of seed grown individuals, even with a serious threat there is likely to be a few individuals that are resistent.

I grow both commercial plants and lots of plants from seed. Yesterday I collected seed from a nursery cultivar! Gorgeous Ilex verticillata growing in front of a commercial property, with lots of plump red berries, which it was obviously selected for.

Terrene, how dare you defile your yard with those cultivar seeds?! (I kid). At its worst, usually under an old oak stand, common buckthorn in this region is able to truly become the only species with any chance at regeneration. Sure, the big old trees towering above are not threatened by this shrub layer, but there is no chance for any regeneration whatsoever. The ground is far too dark with all that buckthorn. That's what I'm talking about. Zero chance for any regeneration other than the buckthorn itself, which seems able to handle its own shade with ease.

+oM

I make a point to include native trees and shrubs for many of the reasons others have mentioned, but I do not feel obligated to restrict myself to them.

I do think it prudent to avoid exotics that spread easily without my deliberate encouragement.

Rosefolly

Tom, your point reminds me of something that happened close to home. They had to reduce the deer population and so they thought a brilliant idea was to "reintroduce" what was considered to be a native species, the wild boar. Turns out, the wild boar propagated far beyond expectations and led to a decrease in diversity. And also led to unpleasant encounters in the local villages. So much they had to recruit tons of hunters to go out and weed down the population. Locally that is still regarded as the golden age of hunting...

Glossy buckthorn, that is rhamnus frangula, isn't it? Funny thing if that one is invasive, it is not here where it is native. It is common in many places, but never that common. Of what reason was that plant brought to america in the first place, it has no real garden features? Actually one of the uglier bushes imho. Common buckthorn should also be native here, but I have never seen any because they are so rare.

One of very few american trees that seem invasive here is the Grand fir, abies grandis. It does not spread very far though, but there are lots of seedlings in all sizes around every mature tree.

I've always figured the prudent thing to do would be to plant mostly natives, but include a few exotics for form, color, fragrance, whatever. Also, it's probably not wise to plant exotics in undisturbed natural areas. However, the sad truth is that very few undisturbed natural areas remain - Planting a few exotics in your yard probably won't make a difference. However, I do like my natives, so I will keep planting them.

Can't imagine spring without tulips, daffodils, and hyacinths, though - I choose exotics to blend in with the surrounding landscape. I live in a rural area that is mostly grain fields, with disturbed floodplain forests along the major ditches and streams. While I use spring-flowering bulbs around the house, I don't put them in my woodland garden along the creek - I use natives instead. I enjoy the songs of wood thrush, towhees, and other forest birds - They need high-quality, lush forest to thrive, so that's what I'm planting at the periphery of the property. Our house backs up to a sizeable stream surrounded by a 500-foot wide woods along the length of the stream - Forest birds and critters thrive back there, and I'm trying to improve the habitat. Right now, it consists of hackberries, ash, and honeysuckle. Not much in the way of quality natives - The floor is covered in garlic mustard and water hemlock.

A point that is taken to extremes is using plants that would only be found in a 50 mile radius from your area - For me, that would exclude many "native" ornamentals, such as native azaleas, silverbell, etc.

Surely there's a happy medium.

Glossy buckthorn = Rhamnus frangula aka Frangula alnus, Common buckthorn = Rhamnus cathartica

Both are quite invasive, but the glossy seems worse here. Huggorm do you live where it's native? Isn't that how it works, in its native range it has competitors to keep it in check. Boy what an adaptable plant, grows like a champ in dry, lean, full sun, but thrives in shady wetlands! And has no competitors over here. Sprouts like crazy when you cut it, I use herbicide on the cut stumps. I consider it "controlled" if I keep the fruiting specimens more or less removed. Kind of an ugly plant too, makes me wonder who the genius was that decided to introduce it in North America.

Jimbob, what a shame those invasives are probably choking out your herbaceous layer. There might be some nice native stock under there.

I love my non-natives too, greatly enjoy the lavish blooms of Peonies, Foxglove, bulbs, etc. in the spring and the tropical annuals in the summer (as do the pollinators), but they are highly unlikely to march away and take over the countryside.

But glossy buckthorn has no competitors here either, and no animal would eat its foliage. Yes, I have noticed that sprouting, it is almost impossible to kill it without herbicide.

It was used for making high quality charcoal for gun powder in the old days, maybe that is why it was introduced to America?

and no animal would eat its foliage

I imagine that insects are eating the foliage in modest amounts.

Not sure what you mean about "has no competitors"; it doesn't have to fight it out with another plant to stay in check. There are probably dozens of natural forces at work that keep a plant in check in its natural environment. Perhaps the seeds don't germinate as successfully there as they do here either because of moisture, temperature or weevils, or ....

wisconsitom, there's plenty of total NA species, but one thing in the east that isn't present (except for boreal forests & isolated high altitudes) is a spruce. Norway spruce grows well here, isn't invasive, and provides that unique effect (yeah, I know, ho-hum for the Pacific NW). And I've seen bird flocks camping out for days feasting on large cone crops.

Is Red Spruce really that finicky? It seems to grow alright in New Jersey, though its still fairly young.

I've got some red spruce growing fine in Central Indiana - It is also fairly young, but the needles are deep green, and it is growing well. There are some pretty big ones at the Morton Arboretum in Chicago that have done well. It seems to thrive on high humidity and rainfall.

I've also got white spruce (Picea glauca) doing pretty well.

We've got quite a few old Norway spruces around here - Red-breasted nuthatches seem to like the seeds.

Norway spruce is pretty dominant here where it is native though, with 42,8% of all trees. Handle it carefully!

Hey Beng, not sure what your intent was in telling me that-I'm growing thousands of NS up at my tree farm/reforestation project. I loves them things! Maybe that's what you meant? I totally agree-obviously! Now there are native white spruce up in that area. But not in my chunk of woods. I'm actually planting a few of those too.

+oM

And who said native plants were boring?
{{gwi:487169}}
Taken at Mt.Cuba Center in Delaware. Natives include tulip poplar,Flowering Dogwood,American Holly, Rosebay Rhododendron,and New York Fern.
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Also taken at Mt. Cuba Center. It features tulip poplar, dogwood, virginia bluebells, and wood poppy.
{{gwi:487172}}
Natives here include Oakleaf Hydrangea behind bench. Bottlebrush Buckeye to the left of the bench and Silky Dogwood to the right of the bench. The red flowers are Indian pink.

Greenthumbz, those are gorgeous pics!

I've heard that there are a couple of trees that are not native to North America but are used by significant numbers of native insects.

1) Malus/Crabapples - native, hybrid, or exotic, Douglas Tallamy's book stated that the leaf chemistry is so similar that North american insects will use all species. This certainly bears true in my experience. I've got lots of crabs, a few specimens and a crazy wild thicket full of them in back,and they are bird magnets, not just for the fruits in the fall but for the nectar and insects in spring and summer.

2) Picea abies/Norway spruce - don't have any personal experience, but was told this by an ornithology student at Cornell who was doing a study on the subject

Oh, wanted to add, it is interesting to me that some species of butterflies that are native to North America have adapted to use non-native plants as hosts, with lots of success (and some failure to adapt). IIRC, the Butterflies of Mass. website called these leps "switchers".

For example, the Black Swallowtail (Papilio polyxenes) is a North American native whose native host plants almost all grow in wet meadows. However, they adapted and also use a variety of non-natives and agricultural plants such as parsley, dill, Queen Anne's Lace, etc. Their population boomed in this state when farm land was maxed, and they were consider agricultural pests.

Especially the first picture is just amazing with the trees and the mist. Looks like a scene from "Lord of the rings"

For example, the Black Swallowtail (Papilio polyxenes) is a North American native whose native host plants almost all grow in wet meadows. However, they adapted and also use a variety of non-natives and agricultural plants such as parsley, dill, Queen Anne's Lace, etc.

It is important to know that the plants they switched to are in the same family (Apiaceae) so they have similar chemical compounds to the native hosts.

Another one is the little, pretty Ailanthus webworm moth that eats the non native Ailanthus.

wisconsitom, I'm supporting your efforts, of course. :)

I don't think the native spruces will grow to the size & long lifespans of Norway spruces, tho I have seen occasional white spruces of good size here. Both the natives do poorly south of zone6.

Another one is the little, pretty Ailanthus webworm moth that eats the non native Ailanthus.

Yes, Ailanthus is in the same family (Simaroubaceae) as the insect's original host, Simarouba spp.

Quite right, Beng. The DNR forester with whom I work said much the same-that NS would outperform the native spruce species. I already thought as much, but it's always nice to get confirmation from others!

+oM

If we are talking about adaptability, the norway spruce is a winner. The native spruces are very specific about where they grow; most prefering acidic soils at high elevation and or bogs. Norway spruce will grow just about anywhere. Now their wildlife/insect value is limited compared to the natives.

A large issue concerns the actual provenance of such trees - for example, how are they propagated? From where? Are they grown locally or imported? Since the UK is now on the brink of yet another tree extinction process (fraxinus chalara), there are pressing issues considering the bio-security of importing plants balanced against the insane fashion for 'instant' landscapes (Chelsea Flower Show, hang your head in shame. Trees are regularly imported in containers with up to a tonne of seething, microlife ridden soils. This lunatic desire to have whetever one wants as long as there is enough money to buy it ultimately impacts on us all so questions of 'choice' are moot.