Is there a particular reason you want silver maples? They tend to be relatively weak wooded and have a lot of surface roots. Many people here consider them to be something of a weed tree. Generally large transplants tend to suffer more transplant shock and take longer to root in than smaller trees.

Thanks, hostaholic! I'm looking for something relatively fast growing and tolerant of quite moist soils. I was hoping a silver maple would provide a little shade in a few years, be fairly hardy to MN, relatively low cost, and able to cope with some rather moist soils during the growing season (believe I have a shallow groundwater table). My parents had a nice one in their backyard when I was growing up, its still alive after 20+ years. I'm open to other suggestions, but I'm very curious if the notion of planting on the high end is a good idea, assuming one will likely not survive to maturity.

I have since moved but I planted 2 silver maples 30 years ago that are beautiful large shade trees. They were about 2 ft. tall at that time and grew fast. If you are faithful about caring for the trees I would plant them where you want them and only two if that's what you want. They are quit hardy & will grow fast. Yes they are considered weed trees and will produce lots of helicopter seeds. They also will give wonderful shade.

I had posted a link yesterday don't know where my post went. But here is site that might give you some useful info. If silver maples are what is best suited to your needs, then go ahead and plant them. I just wanted you to be aware that like any fast growing tree they are weak wooded and the roots do tend to rise above the ground and can cause difficulty mowing around them as they mature.
I'm not quite sure what you mean about planting on the high end.The newest research has shown that proper planting depth is one of the biggest factors in preventing stem girdling roots which cause tree death. When planting the trees you want the root flare visible above the soil and the first lateral root should be even with the soil surface.

University of Minnesota Extension Service
Containerized Tree Planting Guidelines

Remove the tree from the container by holding the trunk of the tree with one hand and pushing down on the container with the other hand. If the container does not come off easily cut it down two sides.
The tree may be planted too deep in the pot. Remove the soil down to the first roots. This is where the tree starts to flare out.
If there are encircling roots, slice through them with a sharp knife. Make 3 ��" 4 vertical cuts in the root ball. After cutting, pull the roots apart.
Dig the hole just deep enough so the first roots will be just below finished grade. Do not loosen soil under the root ball below this depth.
Planting site should be prepared 3-5 times the width of the soil ball.

Note there has been a change in the info regarding encircling roots on containerized trees. If the tree is rootbound they are now recommending doing a box cut, cutting down the sides of the root mass on each side to make a square box and if needed across the bottom as well.

Here is a link that might be useful: Trees for MN

If you are set of Silver maples, buy small saplings, like 2-3 feet if possible. They really do grow fast, and starting smaller will insure the correct root structure that will in the end, provide a healthier and more stable (in the ground) tree.

But if you or your neighbors garden, you'll be sorry in the end. The masses of seeds that a mature tree produces will have you cursing, constantly pulling seedlings, and battling invading surface roots in the garden that will easily grow 2ft a year in good garden soil. It is not uncommon for tree roots to venture out twice the height of the tree.

I would prefer a red maple (Acer rubrum) that will still do fine in moister soil. This is not a red-leaf maple. Or, how about a compromise? There are several better crosses of Red maple and Silver maple with much better branch structure that results in stronger trees. These will probably be listed as Acer x freemanii cultivars.

Silver maples are one of my favorite trees for natural woodland landscapes, wildlife value, general hardiness, quick growth and shade, ease of growing from seed, ease of transplanting saplings, massive leaf production for fall collection and composting for the vegetable gardens, firewood, and sap harvesting for syrup. I have around 45 of them on my property and they suit my needs just fine, and I would never want to go without them.

That being said, they are one of the worst varieties to use as a landscape tree in an urban environment. The exception is if a person only intends on owning a certain piece of real estate for fifteen or twenty years and wants some quick shade or to have an established tree on-site to add value to the property at the time of eventual resale. The next owner will then be the one who has to deal with all the major negatives of having a maturing tree of this variety on the property. Many house-hunters are ignorant of tree varieties and will not even think to consider potential tree issues when buying a house. They will see a healthy tree in its prime, putting out wonderful shade, and will only see it as a positive feature of the property. Caveat emptor.

The negatives of this variety include relatively short lifespan (for a tree), exposed roots, shallow root balls making mature trees susceptible to uprooting and blow-down, perpetual shedding of small branches, lots of dripping sap in spring (attracts flies, dirties house siding, windows and lawn furniture, and is not good for automobile paint), brittle main branches susceptible to breakage due to snow or ice load, very soft wood susceptible to wound rot and insect damage, suckering at the base of the trunk, profuse amounts of bud scales and finished blooms everywhere in spring during the budding-out process, and profuse seed production in early summer that quickly clogs roof gutters and creates volunteers everywhere (and I mean EVERYWHERE - even in the gutters if not properly cleaned out).

We bought a home with 3 enormous beautiful silver maples 4 years ago, and we're down to 1.5. Despite the negatives, I do love them. Yes, millions and billions of helicopers. They drop branches like crazy, but I haven't noticed the sap problem. I'm sure we won't replace them with silver maples because of the downsides.