Best bet is to look around your neighborhood or city.

Imagine a southern magnolia. That thing is going to be HUGE if grown in the south east. In st louis, it will probably live at least.

Shade generally makes trees more narrow than open grown individuals. Imagine a forrest full of skinny treees reaching for the light.

Maries, what are ya planning on or picking between?

Trees almost never stop growing until the very end. They almost always put on caliper and stem elongation each year up until the very end in late senescence.

But to the question of 'reliable sources', all are going to tell you environmental factors are a variable that determine ultimate size. So what tornado said is true - your neighborhood is the best guide,

For one tree I have it narrowed down to a Paperbark Maple, Triflorum Maple, or Ironwood but haven't ruled out a Pacific Sunset Maple or Norwegian Sunset. 20-25 wide is ideal but need a reasonably high canopy too.

For the other tree I want a Beijing Gold Pekenesis if I can find one. If I can't I'm not sure what option 2 would be. I want something that is shorter than tree one and 10-15 ft wide.

"...when looking at trees I sometimes see big discrepancies in the projected height and width..."

The figures you see on nursery stock almost never represent projected ultimate size. They generally represent typical values for a site with average conditions, located in an average (of the range applicable for that plant) zone, after a certain number of years.

first.. you take the common name..

then google for the latin name..

then goggle the latin name..

then flip to the images side ... and you ought to see hundreds of pix of the trees you are thinking of ...

height of canopy under the tree .... is a function of you sawing on the tree.. and training it up to the height you want.. they dont mysterious grow that way ...

while at google.. add: annual growth rate .... and presume it will grow at that growth rate.. once established.. for your lifetime.. and 50 years after ...

i will do one for you at the link

Paperbark Maple .. gave me
Acer griseum .. to which i added annual growth rate, which gave me
Annual Growth Rate: less than 12 inches .. and scanning down the page i see 6 to 12 ... etc ..

and then you will flip to the IMAGES side .... a button near the upper left ... in google ...

and you can see it can be pruned into a myriad of shapes and sizes ..

now do that for the others... and you should be in a better way as to SEEING things...

good luck

ken

PS: if you have any dreams of gardening under your tree .. NEVER buy a maple... if you just want lawn.. maple is good.. for the first 30 years ... then even that wont grow under them .. its about your priorities ...

Here is a link that might be useful: link

Ken - thanks for all the info.
Don't some trees normally branch closer to the ground though even if a single trunk?
Why no garden under a maple? Does that include these smaller ones?
So maybe the Ostrya virginiana would be the best choice? Or from the chart in your link the China Snow Syringa pekinensis might be another option.

The Pacific and Norwegian will likely be on Norway understock so you won't be able to garden under those in the future. Not sure of any growers using A. truncatum for understock.

The A. griseum and A. triflorum will not be a problem to garden under. These are slower growers, I'd say the former at 6" and the latter of 9" around here.

I have both and seen several (mature) plants growing nicely at the Chicago Botancial Gardens.

Ostrya virginiana is the fastest growing (up to 18") of all the options when young but slows down quite a bit with age (call it 6").

whaas - The Pacific and Norwegian Sunset maples are both Acer truncatum x Acer platanoides. Not a clue what that actually means though and if that changes whether I could plant under these.

What about Acer tataricums? I called Minor's and someone there was discouraging the Paperbark due to our zone and possible die back from the cold. I haven't heard or seen that in any other research though.

This post was edited by maries1120 on Fri, Apr 5, 13 at 14:16