Jeffries in Manitoba has 3 cultivars of sugar maple: Unity, Inferno, and Lord Selkirk. The latter is actually the seed run root stock when the graft didn't take, and is my preferred cultivar. They haven't told me where they get their seed, but they won't sell it. Sigh. Looking at the native range of SM, and the zone maps, zone 3 is not unreasonable: Any of the northern states at higher elevations seem to be zone 3. The place with the best conditions for prairie hardy seeds would be around Bemidji Minnesota, up to the SE corner of Manitoba. Might be around Lake of the Woods too. But Jeffries has been selling sugar maples on the prairie for some time. Some of them may be starting to set seed. I'd like to trade, or buy a bunch of SM seed if you are in a cold dry part of the world, and have a sugar maple where you can get ahold of the seed. Seeds ripen shortly before the leaves drop in fall, and are yellowish-green when ripe If it's your tree, easiest way is to put tarps down, let the seed fall, and sweep them up. If they are a street tree, sweep the street. I'll sort out the rocks. Shop vac works too. *** I'll pay Schumacher's price: $13 US or $20 Can + shipping for a pound. (Adjust for dirt and grass.) If you have a large crop, I'll give you a list of possible buyers for it. My dream: Grow sugar maples by the thousand for sale to people who are losing their poplar bush.