Current recommendations for street trees

I am following ViburnumValley's suggestion that i start a new thread for any help from any or all of you.

I live in a very small town , Tonasket, WA, that is east of the Cascade Range of mountains. It is desert area and we just had four years of drought. This fall and early winter through Dec. was colder than normal, Then Jan. has been warmer and wetter than normal.

I am a member of the towns new Tree Board, altho I do not live in town, but am a garden club member and the tree board is made up of 4 garden club members and several other mostly people of other organizations that are interested in trying to make our town more inviting. Hwy 97 one of the main north-south hwys, is the main street of our town. Right now the board is trying to get an ordnance passed for what rules, etc. are necessary for the tree board. After that we want to be appointed a Tree City and then we can apply for a grant or grants so that our small town can afford to buy, plant, and care for city street trees.

What suggestions do you good people have for trees that will likely grow without too many problems under our somewhat difficult conditions. So far we have ruled out acers-maples, as other towns up and down the vallley have all had problems with them, too hot, too windy, and too dry. The summer temps, range from 80s to a few days in the 90 to 100 degree temp.

A great variation with winter temps from (well I have lived here all my life and I have seen 36 deg. below zero) average 10 deg. above for a few nights, and not much snow. So far this winter got down to 5 deg. above for a couple of nights.

There are power lines above the street on one side that we have to be careful that the trees under those lines do not grow too tall at maturity. The trees need to be somewhat columnar so that the business windows are not obstructed too much. The way in which the trees will be watered has not been determined exactly yet. and I think most of the trees will be planted in box type containers that can be lifted out of the ground, which will hopefully make it easier to replace the trees if necessary. There are a couple of parks where if for some reason the trees do not seem to be growing well they could be moved to one of the park areas.

Right now we are planning to choose 3 varieties of trees. From all the info we have so far acquired we are thinking of Pyrus calleryana 'Chanticleer" which is not supposed to be vulnurable to the breakage than many pears are subject to..

Guy, how fast is the emerald ash borer moving west. And are all the ash trees subject to that pest. I have 2 ash trees, I planted Fraxinus augustifolia 'Raywood' 10 years ago when I moved here and so far it is doing beautifully. Two years ago I planted 2 more Ash, americana Autumn Purple', one to provide shade for my metal gazebo and one out in the woodland garden area, just because the foliage is so pretty. I am a little afraid of the Patmore Ash, maybe growing too tall.

Thanks for any help. DonnaS

At this point we have to link the Ohio State Street Tree evaluation project.

http://ohioline.osu.edu/b877/

SB

The emerald ash borer can move several miles per year on its own, but it is leapfrogging hundreds of miles because idiots move infested firewood around. I would not plant any native ash right now as a major component. There are so many of them already, and even if the borer is struck down by some miracle (and that's what it will take) we need more diversity.

You might want to copy and paste in the other comments already posted, including the new one on the parallel thread just started.

Guy S.

Please please please reconsider lining streets with Pyrus calleryana 'Chanticleer". It is one of the Stepford Wives of Calleryana Pears.

The search engines for DG are currently unavailable to pull up threads on Callery Pears but here's an article that is timeless-
http://www.agnr.umd.edu/ipmnet/5-8art1.htm
It was written about 6 years ago after many people began noticing that Calleryana Pears were escaping cultivation. Since then, we've learned so much about Callery Pears.

If I can find the threads for you to share with the Tree Board for your town, I will post them. It is my understanding that many people have printed off threads from here and shared them with committees that were considering the use of Calleryana cultivars which is what 'Chanticleer' is. I know these trees are going cheap but that is due to heightened public awareness.

I am not a professional, but I would say that you need more than 3 different types of trees, simply for the biodiversity. SB

Here's what I said on the other thread:

Guy S.

Then Scott started a parallel thread about the same time you did, with much more info:

Guy S.

John ("Viburnum Vandal" -- hee-hee-hee!) had begun with:

OK, I'm done cutting and pasting -- gotta go get some work done! Carry on, somebody . . .

Guy S.

While I'm reluctant to suggest trees for you since I know so little about your growing conditons, I will simply ditto Scott's comments on A. buergerianum. I ran across this one while spending some time in Virginia. If memory serves me correctly, this tree was planted during the 1960's. It has a nice upright habit with attractive bark. There's also a recently released cultivar named 'Streetwise' that might be worth checking out. I wish I could grow this tree. The only concern is if it would hold up to the hot, windy conditions you mention. What are some of the Maple species you mention that are struggling?
http://img.photobucket.com/albums/v145/maackia/Woody%20Stuff/Deciduous%20Trees/HPIM1497.jpg

http://img.photobucket.com/albums/v145/maackia/Woody%20Stuff/Deciduous%20Trees/HPIM1498.jpg

This message was edited Jan 27, 2006 10:48 AM

Im not sure what zone you are in but the "Natchez" crape myrtle makes a nice small tree to about 30ft.,it is pest resistant and said to be hardy to zone7. The blackjack oak may not be flashy but it is a nice small oak. There is a smaller version of the post oak called sand post oak, it should be very drought tolerant. And what about the "whiteshield" osage orange, it is fruitless and thornless. I have heard of some dwarf hackberry trees (celtis pumila) also. I think forestfarm sells them. Redbud is often recommended but I have found that they prefer a little shade rather than being in the hot sun. There is a southern version of the sugar maple called florida maple (acer barbatum) that may be hardy in your zone. They don't get nearly as big as the northern species but I have found them to be rather slow growing. Those are just a few of the trees that come to mind.

Just a suggestion, Russian Salt Tree (Halimodendron halodendron) when grafted on Caragana is a nice small tree (shrub) with purple-pink blooms in June/July, extremely heat/drought, salt and cold tolerant, grey-green foliage and "tough as nails". Maybe for planters or intermittent between larger trees. It's hardy to I believe Z2. http://davesgarden.com/pf/go/31913/index.html

I also think Starhill's suggestion of the Kentucky Coffee Tree might work too. Have you looked into Russian Olive (Elaeagnus angustifolia)? I'm also wondering about Hardy Rubber Tree (Eucommia ulmoides) - http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/trees-new/eucommia_ulmoides.html
Having worked with it I think it might be a good candidate as it seemed clean, tough and drought tolerant. There's a local nursery that had quite a few I used to work at. Thornless Yellow Honeylocust (Gleditsia triacanthos var. inermis 'Sunburst) http://davesgarden.com/pf/go/85607/index.html would add a bit of yellow colour and it can be stunning to see. While we're at it Yellow Black Locust can be quite stunning and tough: http://davesgarden.com/pf/go/53848/index.html
You mentioned Fraxinus a. Raywood which I have always admired and felt was underutilized as a street tree. For something a bit different, Interior Douglas Fir (Pseudotsuga menziesii glauca) as you still are westcoast and this form is an inland hardy form.

I hope some of this helps.

What's used as street trees over here:

Commonest among older plantings:
Sycamore Acer pseudplatanus
Swedish Whitebeam Sorbus intermedia
Both have very good survival rates in urban conditions

Also once abundant tho' very few DED survivors left now: Wych Elm Ulmus glabra

Less common though fairly frequent:
European Ash Fraxinus excelsior
Common Lime Tilia × europaea
Wild Cherry Prunus avium
Assorted Crataegus and Malus cultivars

Commoner among recent plantings:
Italian Alder Alnus cordata
Turkish Hazel Corylus colurna (only in last 5-10 years or so)
Vosges Whitebeam Sorbus mougeotii
London Plane Platanus × hispanica
Norway Maple Acer platanoides
Field Maple Acer campestre
Silver Maple Acer saccharinum
Broad-leaved Lime Tilia platyphyllos
Caucasian Lime Tilia × euchlora

- - - - - - - - - - - -

Fraxinus angustifolia 'Raywood' is NOT a good choice for a street tree, it is nearly as fragile as Bradford Pear.

Resin

Another suggestion would be to take a drive to the tri-cities and see about a recent revitilization project they did and what they used. Talk to the city arborist and get some real feedback from a like-climate. Here's the article: http://www.tri-cityherald.com/news/2002/0510/story4.html This article also covers storefront coverage by trees and a simular stumbling block.

I'd also recommend finding someone with alot of political power to get those powerlines out of the downtown core. They only say "low-end". If you're going for revitilization I'd imagine proper pavers will be installed and an irrigation line can be installed under the pavers in a conduit that can be plugged into as you add or remove trees. Is there a town park/square?

I like the idea of containers, easier to clean, away from the town dogs, and as you say easy to replace. Makes your own soil environment. Soil tests always a good idea when planting in a park environment. One never knows what is under the first four inches. Think about planting extra in some location near water that you can use as replacements if anything untoward happens. Look out in the country some with an open eye; can you bring a grouping of what you see in nature into the town so the contrast is not so foreign?

New York City has many Gingkos that have survived for many many years as street trees. And NYC has some pretty serious growing conditions to put up against trees. All of the Gingkos I've seen there over the years have survived beautifully & seem to do well.

I think Growin absolutely hit a home run with burial of the utility lines. Problem is, that's about as easy to get done as reducing the deer herd. But give it a shot -- it would change your entire environment and standard of living as well as your arboricultural options.

I do have to disagree about the Russian olive though, due to its disease susceptibility in humid climates like ours here and (more critically) to its status as a serious invasive species. Actually, the entire genus pretty much could be considered invasive.

Regarding ginkgo and power lines, that reminds me that I've seen it used in southwestern China for living telephone poles. They plant it in very small holes in the pavement, whack it back to a central trunk with a few short, well-positioned "cross-arm" branches, and string the wires on it, then pollard it back to the original size every few years as needed. Makes you sick to see that done to a tree, but the thing really is a tough nut!

Guy S.

Thanks Starhill, to carry that on an adjacent conduit with power would make it easy to plug in Christmas lights, provide power for Street Festival, markets, sidewalk sales, etc.

I was wondering about the Russian Olive. I still like the idea of the Hardy Rubber Tree & Russian Salt Tree.

Hey Guy, please share in a tad more detail why you don't feel Russian or Autumn Olives would be good choices... skip the susceptibility to disease in milder climates ;)

Yeah, I like the Hardy Rubber Tree idea, as well. Not the most spectacular beauty queen in the nursery, but a good, tough, serviceable tree. A nursery I worked for had a line of them growing in parking lot gravel.

Also Resin's idea of using Sorbus. We can't grow them around here because of disease issues, so I know nothing about the different species. But I have seen numerous sorbus species and cultivars growing beautifully at Washington Park Arboretum. I think they do much better out there.

I also like his idea of Italian Alder, another tough customer and surprisingly attractive.

Scott

Greetings. I'm an urban forester in Pocatello (SE Idaho, Zone 5a) where we've been working on revitalizing our 'old downtown'. We were fortunate that the entire street and sidewalks were pulled out. Structural soil was laid beneath the entire walk area and so the new tree roots will have full run to grow and interlace rather than being constricted in 'tree coffins'. Drip irrigation and electrical lines for lights installed.

We chose 'clean' medium to large maturing trees for the midblocks so that their lower branches can eventually be pruned to a height that allows pedestrian passage (without being hit in the head) and business sign visibility. And we look forward to tree branches interlacing overhead. The sidewalk/street intersections bulb out and so we chose to plant smaller, broader, ornamental trees there, replacing many of the original Callery pears.

Mid-block species:
Honeylocust - Gleditsia triacanthos var. inermis 'Imperial'
Hackberry - Celtis occidentalis
Ginkgo - Ginkgo biloba 'Autumn Gold'
Zelkova - Zelkova serrata

Intersection species:
Red Jewel Crabapple - Malus 'Jewelcole'
Lavelle Hawthorn - Crataegus x lavellei
Callery Pear - Pyrus calleryana 'Chanticleer'
Sargent Cherry - Prunus sargentii 'Columnaris'

Very large trees in the few interior parking lot spaces:
London Planetree - Platanus x acerifolia
Bur Oak - Quercus macrocarpa
English Oak - Quercus robur

Sorry I seem unable to place scientific names in italics but you get the gest/jest. Hope this helps.

-Sander

Thank you all so much for your suggestions and for taking the time to send them along. I have made a copy and will have my gardening friends read and discuss. I grow some of the trees that have been suggested but of course it is different growing in my yard than growing in the heat etc along a city street.

I don't know exactly which maples were tried in the other towns, both to the north and the south of Tonasket, but i do know the consensus of opinion was that maples were not satisfactory as city trees in this area.

I have a Kentucky Coffee tree, only 3 years old in my woodland garden area, and from what I see and read I am afraid it is a tall growing tree.

I certainly wish that were a possibility that we could have the utility lines buried and new sidewalks, but we have already been told that there is no possibilty of that, just no money available.

Thanks again and as I said any help is much appreciated.

DonnaS

I'm surprised to see silver maple as being listed as a street tree in the U.K. It's not even very well liked here in it's native home.

I was only glancing through this, so I honestly don't know if this was covered, but I hope you don't put Norway Maple on your list of trees to plant. Norway maple. Bad.

Just my humble 2 cents there.

sthroneb...Bur oaks in a parking lot, I love that! An oak/asphalt savannah. SB

I can get a photo in the next day or two. Because of our cooler summers here, it doesn't grow so fast as it would where you are, which may make it less brittle (or there again, maybe not, I have seen some which have shed branches - it may just be that UK urban foresters are/were less aware of its bad habits). It also doesn't seed itself here.

Resin

Hey growin, Guy never came back to comment about the Russian Olives. Shortly after the Feds placed Russian Olive on their Hit List, The State of Utah followed by formally identifying it as a noxious weed and they banned it for the damage it had wreaked and continues to wreak in natural areas. It is against the law to sell ir or plant it there. After Utah added Russian Olive to their hall of shame list , I believe quite a few states followed suit based on ongoing research. Washington appears to have been one of the states that may have banned the sale and planting of Russian Olives based on the invasive characteristics this plant has demonstrated. I know it is one of several plants that Illinois may be adding to our list... if we can get past the politics. http://plants.usda.gov:8080/plants/nameSearch

And I forgot about a current thread that addresses some of the issues of Calleryana Pears which would include Chanticleer-
http://davesgarden.com/forums/t/571565/
If you are interested, here is a direct link to one of the threads I referred to earlier where a few posts mentione some of the consequences of planting species such as this-
http://davesgarden.com/forums/t/563787/

Hope this helps lay out some of the concerns regarding Russian/Autumn Olives and Chanticleer/Calleryana Pears.

Equilibrium, I was wondering but not as aware as you guys on the invasive properties of Russian Olive. Now I'm a bit more aware. Here it makes a nice shrub that always looks good and doesn't self-seed. Just like Albizia. I remember seeing a Russian Olive in Benton City and it was unkept looking on a city street. Pears have problems in our moist & humid climate. Cheers.

Hi rutholive,
This may not apply much to your local conditions, but Seattle has a great guide for street trees http://www.seattle.gov/transportation/treeplanting.htm#recommend, and we can even apply for FREE trees!

Had to laugh at the suggestion to remove and bury powerlines... The cost is obscenely prohibitive. It's about $1000 per foot of frontage, to be borne by the homeowner, and everyone on the street would have to agree to pay. For some, that would be more than their house is worth! Sorry, but buried lines make (economic) sense in brand new developments, or those that can afford to switch.

Jermainiac

I really appreciate all the good info from you great DG people.

Russian Olive is an ugly tree ? specimen in this area.

I have a three year old Platnus acerfolial , London Plane Tree, planted about 10 feet out from my back slider door on west end of my house. It is already about 20 feet tall, which is great for me, since it creats quite a lot of needed shade for that end of the house, but I am afraid it would grow much too large for our street tree locations.

I am using your suggestions for search on Google, and getting a lot of info.

I don't remember that anyone has suggested Sorbus, Mountain Ash. So I am wondering if there is some problem with them that I am not aware of. I grow four varieties in my yard, which I realize is much different than trying to grow them in a sidewalk situation.

Thanks again for all your help. DonnaS

Hi rutholive,

The only concern I'd have with Sorbus is fruit debris & die-back of stems. The fruit can make quite a mess here and stains walkways.

The powerlines suggestion was to move powerlines away from storefront, to backlane. The burried service lines were smallscale suggestion. Not what you interpreted. Simular to a standard home installation but slightly bigger. With persuasion the power company could be coaxed into moving the lines as it makes "economic sense" for economic growth for revitilization.

Did you have a chance to read the tri-city article and where they got extra funds? sthorneb's suggestions sound well thought-out.

I'm going to start a new thread on this utility subject, after responding here:

Jermainiac wrote:

The utility companies count on you buying into that reasoning, and then never changing anything. It's the way of most all large institutions, inertia. I invite some folks from Madison WI to speak to forethought in burying power lines, dating back to at least the '70s if I recall from my youth. And ask anyone near a rapidly expanding metro area if they'd like to be back on their old septic system (with all their neighbors, new and old) instead of connected to a modern sanitary sewer hookup.

There are some electrical engineering principles involved, to be sure. Some very high voltage/watt/energy lines are more difficult to deal with, but most service can be provided underground (which is why new developments can and do so). The approach should be incremental: add a bit to monthly bills (or to the kilowatt), build up an account to a sufficient level, and start going about the business of eliminating the problem. Obviously, mind the store about keeping their feet to the fire and actually doing the work! Also demand a plan of attack by which the order of priorities are approached and dealt with.

The same argument has been made for years about using directional boring (tunneling) techniques for utility installation around mature trees, instead of trenching. It all revolves around the assumed value of what is being impacted. Many/most engineers and utility companies place no value or nearly none on trees. Imagine if they placed none or near none on your house (or garage, or pool), and decided to trench right through it. Unacceptable to most. Utility companies also are loudly mum on the sweet deal they have with easements. Most pay NOTHING for use of the public domain to make their way through the landscape, but vociferously admonish against any expense to reduce this visual and physical impact.

The link between tree losses due to utility work usually are not made, because the tree doesn't usually die right away. Another huge impact is loss of tree canopy (shade) in cities, and exacerbation of the heat island effect and acceleration of stormwater runoff. Utility companies don't accept any responsibility here, though they may sell you more product when you are hotter in the warm months and build more featureless detention basins to capture the floodwaters.

I have no illusion that this situation will change soon; like most problems, incremental change is as much as one might expect in the near term. I'm not interested in being an apologist, though, or excusing away continued damaging practices. To continue to create maintenance problems and costs by keeping most/all utility lines up in the air (subject to tree and climatic hazards) doesn't strike me as very forward-thinking, but it IS awfully easy.

Whoa, Did anyone take a look at what the Seattle Dpt of Transportation was "recommending" ?
http://www.seattle.gov/transportation/treeplanting.htm#recommend,

Albizia julibrissin. (silk tree, mimosa)

Ulmus parvifolia, U. pumila (Chinese elm, Siberian elm).

Pyrus calleryana ‘Capital’ Pear, Pyrus calleryana ‘Aristocrat’ Pear, Pyrus calleryana ‘Redspire’ Pear, Pyrus calleryana ‘Autumn Blaze’ Pear.

That speaks volume. Have they not updated their website in a few years? Get a load of all the Ash being recommended. Ash is a nice tree but I don't know if recommending them is in the best interests of their tax payers right about now. I suppose I should have expected this given many sites here in Illinois are just now beginning to update sites by removing these types of plants but it sure does always come as a shock when entities that people reply upon for the most current and up to date information don't seem to stay on top of recent research.

Equilibrium, as I've mentioned before but got shot-down so quickly, Albizia is not a noxious weed here. Ulmus - There is a few large American Elm on the next block from where I live. Dutch Elm disease hasn't gotten here yet. Ash is an easy to grow and recommended street tree. Select cultivars do very well and are sought-after. This climate is very different from yours. We don't get hot summers. They have up-to-date information available that is suited for this climate, but, as you mentioned, not yours. I almost got killed by tornados south of Chicago but I don't tell everyone to watch out for them here.

I'll try to interject an interpretation here:

Different exotic trees become pests in different places and at different paces. Albizia julibrissin, if that's the Albizia species involved, might or might not be OK in Seattle on that score, as long as it has a long-proven track record of good behavior. But recommending something that is known to have such problems elsewhere, at least for large scale use as a street tree or ROW tree, doesn't seem prudent, as Dubya's daddy used to say. Besides, who would plant such a brittle, sprawling tree along city streets? Save it for backyards, and only if indeed it is unable to reproduce out there (BIG "if").

The elms Equil is mentioning are not of concern due to DED, which does not harm them. They are potential problems because of breakage (U. pumila), invasiveness (both species, but especially U. pumila), and large size under overhead wires.

I doubt that anyone in North America should be recommending any native ash species for large scale planting right now, with the EAB jumping ahead in hundred-mile increments. It's just not fiscally responsible, despite the previously good performance of ash in some regions. I don't know what ash species are listed by Seattle, but all of the common ones will grow tall enough to impact overhead conductors. Being "sought after" (by those who don't know better) in itself does not distinguish ash from trash, like callery pears or purple plums. It's up to those who do know better to set the standards.

Also remember the comments made earlier about diversity -- if you have lots of ash already, move on to something else. Use 10% as a guide and don't exceed that maximum with any species, and especially with any single cultivar, and double-especially with anything currently under mortal threat from a new exotic pest (like ash). Seattle has a climate that can support so many tree species that there is absolutely no excuse for anything remotely approaching monotypic plantings there.

We need to bring Pam (the Seattle GardenGal) over from GW to comment on this -- someone go get her!!!

Guy S.

Many of the species denoted above have already been irrefutably documented as being alien invaders which destroy biodiversity and do irreparable damage in our fragile ecosystems upon which we humans depend for our existence. These alien invaders (invasive non-natives) are undeniably costing the tax payers not millions but billions of dollars. If Canada doesn't have problems yet with any of these species, that's great but plants... life feral cats... and English House Sparrows do not respect property lines whether it is the boundary to a State or to a Country. Our Country does not have infinite resources. I can certainly think of a lot better things to do with around 170 billion dollars a year currently be used to control, manage, and eradicate invasive species and I'd start by funding social programs which are in a shambles down here right now in part due to the need to address all of the Public Health concerns of and or associated with alien invaders of both flora and fauna.

East Coast States have traditionally been more progressive in formally identifying many of these species for what they are. Regarding Albizia by you, I have no idea. Regarding Albizia in the State of Washington, it did not enjoy the popularity there that it did out east and in the midwest however it most certainly is documented as being a major cause for concern in Washington as well as several adjoining states. Regardless of whether a State is able to cut through the red tape to formally identify these types of species for what they really are which is noxious weeds that are injurious to public health is superfluous.

I'm really so sorry to be so blunt but we've got major issues down here in the US with our increased dependency on chemicals as a result of some of these species. We humans are dependent upon farmers to sustain our growing numbers. Our water sheds are at risk.

Education is paramount as most people never get the opportunity to see the consequences of their irresponsible plant choices. For some reason the concept of birds eating fruit and spreading seed alludes people. Think about it. The bird poops out the seed encased in a ready made fertilizer pack of its very own feces. Some of the seed will ultimately land in areas that are inhospitable but some will land in areas where it is not only surviving but thriving beyond our wildest imaginations.

excerpt from here-
http://www.brown.edu/Research/EnvStudies_Theses/full9900/mhall/IPlants/Discussion.html

As Faith Thompson Campbell (1997) puts it, "We should be humble; we may never fully understand the invasion process, particularly for each of the hundreds of potentially invasive species in each of our many ecosystems. One truth is clear: as time passes, many species will spread to new areas or increase in density if controlling actions are delayed."(Parker and Reichard 1998; see Results for the industry's desire for scientific proof)."

Thanks again for all the info and help.

I'm sure we do not want to plant any trees that might be invasive in this area. I am not sure where to go to find a list of invasive type trees for this area. Next time I get to Okanogan some 30 miles, I will go to the Extension office to see if they have a list. Probably the worst pest tree in this area is what locals call Chinese Elm, which I am pretty sure is not correct, but I don't know what the variety really is, has small leaves and spreads by seeds almost everywhere.

I have been googling for info on suggested trees to get as much detailed info as I can before our next meeting the end of Feb.

DonnaS

The "Chinese elm" that is invasive for you is the Siberian elm (Ulmus pumila) that Equil already warned you about.

The problem with relying upon local invasive lists is that they usually are compiled by people who merely document what's already out of Pandorra's box and can no longer be contained. The POTENTIAL for invasiveness is what you need to look at. Massive production of wind-blown seed (e.g. Paulownia), bird-disseminated seed (e.g. Lonicera), close relatives of known invasive species, etc. all should inspire caution.

Go ahead and talk with your extension people as a starting point, but also seek out advice from some proactive source like a state native plant society. Then step back and evaluate what each says. For example, if someone tells you callery pears or Siberian elms are not invasive, they should lose any credibility they might have had with you. And if they tell you to plant absolutely nothing but natives, that's pretty much the other extreme and has similar credibility problems. Find the middle ground, always preferring natives but not excluding appropriate exotics.

Always think diversity, and consider the toughness, growth forms, and messiness characteristics of any species used for street trees. Don't plant coconut palms or pitch-dripping pines overhanging parked cars. Don't plant trees with soft fruits like callery pears or pawpaws where their fruits will land on sidewalks. Watch out where you plant thorny trees. Avoid those with weak structure, whether from genetic predisposition or from improper pruning in the nursery. You know the drill!

Guy S.

Guy's recommendation to seek out assistance from a native plant society is great. I've found most of the Master Gardeners associated with the Extension Offices to be focused on other areas of concern and our particular extension office will come right out and tell people they don't have anyone on staff who is capable of addressing the concerns posed by invasive species so I've gotten a few calls as a direct result of having my name passed out to try to help a few who have inquired. Interesting because I'm a neophyte and am still struggling to bail myself out and in personal need of of all the help I can get. I'm probably going to get nailed by some of my native plant only friends but... I would agree wholeheartedly that if somebody tells you to plant absolutely nothing but natives, that's pretty much the other extreme and has similar credibility problems. Actually, I'd go one step further and state that serious credibility issues would exist for me given there are thousands of species out there that are introduced that substantially increase the quality of life for us humans.

Chinese Elm (Ulmus parvifolia), also sold as the Lacebark Elm which sounds really nice and appealing and something attractive that a homeowner would really like to have as a specimen in their front yard, is a big problem by me too... yet it is not formally listed as a noxious weed here in my State or in your State. It happens and fortunately for us it is one of the plants our State would like to get added to our Hall Of Shame lists.

A good thing to know is the Latin name of the plant you are interested in purchasing.

Type it in to any search engine using the binomial and adding the word invasive and or noxious first and see what you come up with.

From there, type the Latin name into this search engine and scroll down to the bottom of the entry and they will have an area designated for invasive-
http://plants.usda.gov/index.html

Here's a good overall where you can look up the plant you want to know more about by poking around here-
http://www.nps.gov/plants/alien/list/a.htm

There's also the Invasive.org
http://www.invasive.org/

National Wildlife's eNature has a nice search engine too-
http://www.enature.com/fieldguides/detail.asp?recnum=TS0714

Other than that, The Nature Conservancy always has good comments on species that are a "problem child".

Best wishes to you. It is so refreshing to run into somebody in a position of authority who is openminded enough to research what is going to go in the ground thoroughly to be in a position to recommend the best possible plants for the long haul.

ViburnumValley wrote this in another thread and I just love it-

Given my City is struggling to come up with the funds to start cleaning up Russian Olives and Bradford Pears lining the streets right now (in addition to other plants already listed by the State as noxious) without unduly raising our property taxes, I wish we knew back 15 years ago what we now know about some of these plants. We would have saved millions of dollars. Thinking globally while acting locally is coming home to rest here but not without a very high price.

I've often wondered why people in the US are so keen on Acer truncatum, considering it is a close relative of Acer platanoides . . .

Resin