One of the odd things I notice about the Asian trees is their late leaf retention in fall. Heck, even my Bradford is still green.

Of all the trees you mention, I don't grow a one. They don't make the cut in my garden. Some are weeds, others are out of scale, and some have no Fall color.
A lot of broadleaved evergreens come from SE Asia and do very well in my garden. The same for a lot of conifers.

The trouble with just planting natives is that it's hard for the garden not to look like a vacant lot. I want to avoid that at all costs.
Mike

I'm not a native purist, by any means, but I prefer the overall aesthetics of native trees and shrubs. A garden of natives needn't look scruffy, there's plenty of garden-worthy plants. Actually, our native plants are more treasured in Europe than they are here! I guess familiarity breeds contempt with most people. Who can deny that a wooded hillside foaming with dogwood, silverbells, and redbud isn't pretty? Or how about a mature beech-maple forest in peak autumn color? Like I mentioned before, native plants are kind of an aesthetics thing with me.

start with a theme for your garden.. then proceed accordingly ...

simplified.. my garden is what ever i can buy ... then conifers and hosta ... and then after starting with the green backbones.. i add the colors.. blues/yellows/etc ... then 'anything but green' ... as in variegated ...

now understand.. i have 5 acres ... i have a lot of ground to cover.. i can not stay in one group of plants... or i would have a lot of mowing to do ...

and finally .. a lot of gardeners.. just want to grow things.. to prove they have the 'unique' ... zone pushing is an e.g. .... which would kind of negate the native argument ...

so for me... when i procure something.. the last thing on my mind.. is whether it is native or not ... its whether is adds to the aesthetic of the collection ... of which.. that is entirely subjective ... as i define said aesthetic .... based on the theme i started with ..

if you want to go 'native' .. all the power to you ... i dont really care .. what your theme is.. make yourself happy .. that is the whole point of YOUR garden ....

ken

Also, certain locations where humans have heavily contaminated the environment are very tough for the best natives.

Out here in the northern Nevada desert, virtually none of the trees planted are native, even the ones that grow well.

All that having been said, I don't think a lot filled with natives is necessarily going to look abandoned. It depends totally on what the owner does with it.

In suburban areas where native vegetation exists as buffers between properties it may not be as much of an issue. But if you look at the averaged landscaped urban yard, with tons of grass for example, there is a lot less food for them when it is planted in non-native ornamental plants.

People report a much increased level of insect, small mammal and reptile, and bird populations when they increase the amount of different natives in their landscape. How fun for the kids! So much to discover.

Yes, you can landscape with natives and have it look "nice". Especially in my area, there are dozens of excellent native trees to choose from.

The native Sycamore is here plagued with various diseases. Native is not necessarily healthy. The native Cercis reseeds like wildfire and often in inappropriate locations (cracks in pavement). Washingtonia is native to California but not to this part of California, where it is an invasive weed.

Also, some non-native trees produce tasty, edible food.

Exotic plants on the market were selected from the whole world's flora for garden suitability. When you throw a net over a particular area and say you are just going to grow what comes from there you have introduced an extreme amount of filtering.

Nevertheless it is possible to produce quite diverse and interesting displays when you start gathering native species together into one spot. Even here where the number of tree and shrub species in particular seen growing togehter in nature is characteristically quite low. When you do come to a wild place where there is a concentration of species the interest level perks up quite a bit.

And it is often apparent with trial plantings like those in arboreta that the local natives are doing better than multiple different exotic species on the same site. And the thing about wildlife zeroing in on native species was supported by a local study done years ago at an arboretum here, where it was determined that native birds were basically passing over foreign species in the same genus and concentrating on the native ones.

But then some of our weediest foreign origin trees and shrubs are dispersed by native birds.

Well sometimes it is the only thing to eat!

I make the small distinction of calling "prolific" reproducers who are native "weeds" and the non-natives "invasive".

Beyond that I tend to select trees that have overall stronger resistance to pests and diseases. Doesn't matter if its native or not.

Beyond that I tend to select trees that have overall stronger resistance to pests and diseases. Doesn't matter if its native or not.

The biggest drawback of non-native species that I can see is when they become invasive. However, most non-natives are not invasive, some are beautiful and interesting, and they can also provide resources for native fauna.

Botann your photo is very pretty, although I don't think a garden of native plants looks like a vacant lot! Around here, disturbed or vacant areas tend to be colonized by invasives anyway.

I sometimes wonder about the widespread use of cultivars, such as an October Glory, in the range of red maple but far from the region the O.G. was native to, and whether spreading pollen and seeds leads to contamination of local gene pools with less well-adapted specimens using as ornamentals (in other words, you plant an O.G. in the extreme northern or southern end of the red maple range, and it pollinates some native red maples in the area).

Richard.

I'm with you Richard, and expressed much the same concern on this very board years ago.

+oM

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.

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.

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.

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.

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. :-)

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.

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.

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

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.

+oM

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.

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.

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.

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

+oM

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.

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

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.

+oM

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

Rosefolly

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.

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.

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.

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

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 ....

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.

+oM

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

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.

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.

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.

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

+oM