Glenn Herbert wrote:That's actually a fairly young sugar maple, by the look of it. It will get significantly larger in future decades, but sugar maples don't tend to have low spreading branches. It will maintain a general egg shape in isolation. The ground level will continue to have mostly full sun except at the north side. If you have good moisture levels in your soil through the summer, you may be able to grow shallow rooted crops there, maybe with the addition of mulch or compost.

I don't see sugar maple roots at the surface like I do white pines, and haven't heard of them being aggressive to neighboring plants. Grasses, brush and mayapples grow right up to the base of the one by my driveway.

Marco Banks wrote:Blueberries and other berry bushes may do alright in partial shade, but I wouldn't want them tucked too far under the canopy. I'd keep your plum trees outside the drip line of the tree, or you'll be frustrated that they never really give you the production that you desire. If you do tuck them in close, can you plant them on the south or southwest side of the tree? From the picture, it's difficult to see the orientation of your garden. If the understory trees are planted on the south side of the sugar maple, they'll get a lot more of that early spring sun before the earth rotates and the sun passes directly overhead through the heart of the summer. Since plums usually mature early (mine are ripe in June and July), that might be a way to maximize that seasonal window.

If you plant on the west side, they'll get that afternoon, late afternoon heat from the sun.

Planting them under the big maple on the north side would be the worst of all possible worlds. I wouldn't want a late ripening tree (late July, August or September) be anywhere where it will not get full sun in those months.

You can always train vining veggies and fruits to reach in the direction of the tree, so that you can utilize that space. Watermelon, pumpkins, cucumbers, gourds . . . they want sun, but you can push their vines that direction. Grab the vine, drag it that direction, step back, and yell loudly, "Stay!".

I don't know sugar maple trees -- are they deep rooted or shallow? How far does the root system extend past the drip line? That might be a variable to think about. If it sucks the ground dry for 20 feet in any direction, it'll stunt anything you try to grow, and the more water you put down, the more that big tree will say, "Thank you" and send more roots to suck it up.

One positive is that a tree that old should have a well established fungal network throughout the root system. Your plums, or any other tree, will benefit from that established fungal network.

Glenn Herbert wrote:22" diameter is bigger than I thought, and means that the bottom of the canopy branching is even higher than the typical 8-12', so sunlight should not be an issue. Competition while it was small would be an explanation for the height of the bole.

Monica Eger wrote:Erin, if you want your squash to grow in a certain direction, it might be helpful to know that they will usually grow in the opposite direction of the first two real leaves. So, if you want them to grow north, place them in the ground so that the first two leaves point south.