Sugar maples aren’t only found up north. Even in the Piedmont, they’re a common sight. To most eyes, they look like a red maple. The two key differences are that the leaves of the sugar maple are more deeply cut, and in the fall sugar maples turn yellow or orange while the red maples turn a clear red or an orange-red. If planted on the right site, either species grows well here.
Red maples naturally grow in river bottoms, which are also called floodplains. They don’t mind having their roots wet—you can find plenty of them along the banks of the Eno River or along New Hope Creek. Paradoxically, the same adaptation that allows them to tolerate flooded conditions also allows them to survive severe droughts. Here’s how that works.
When the floodplains are flooded in the winter and spring, the water displaces the air in the soil. Tree roots need air as well as water to survive. So floodplain trees, such as the red maple, slow down the roots’ metabolism to avoid drowning. This same slowdown also allows them to survive drought conditions. This adaptation explains the surprisingly frequent planting of river bottom species like river birch, sycamore, willow oak and red maple on high and dry commercial sites such as parking lots.
Sugar maples evolved on drier slopes and ridge tops so they come by their drought tolerance the old-fashioned way. Unfortunately, their adaptability to drought doesn’t translate into a tolerance for the opposite condition as with the red maple—wet, poorly drained soil will kill a sugar maple.
If Hurricane Fran did nothing else useful, it at least showed us that roots of even the biggest trees are rather shallow. Remember this when you dig your planting holes. Dig no deeper than the depth of the actual root ball. You want it to rest on solid, undisturbed soil. Save your energy for digging a hole that is at least 1-1/2 times wider than the root ball, so the new roots can move horizontally into loose soil.
Once you’ve planted your tree with the root ball at the same level as the surrounding soil, you need to mulch it to suppress weeds, prevent weed whacker damage and hold moisture for the roots. I use a three-inch layer of shredded hardwood bark mulch covering an area wider than the actual plant hole. I prefer shredded hardwood mulch over pine bark because the hardwood mulch decomposes to a nice topsoil and also because it does not wash away like the pine bark does. This is especially important on a slope. Hardwood mulch will hold its place on even the most vertical slope.
Make sure you don’t leave any mulch against the trunk—you want to hold water near the roots, not the bark. Think of the point where the mulch meets the trunk as if it were the collar of a crewneck shirt rather than a turtleneck. Mulch pushed up against the bark of a tree will hold moisture and encourage rot or it may create a home for rodents who’ll eat the bark.
Both sugar maples and red maples make good shade trees or street trees. They cast a wide shadow and will easily be around for a century or so if you follow these steps and get them off to a good start.