Dogwood trees are the most asked-for tree in our nursery, but they can be a challenge to grow successfully. They thrive in well-drained acid soil rich with humus, similar to the rich compost we see in established forests. You’ll rarely see a mature dogwood tree standing in the middle of a field, since they prefer some protection from wind and sun. Dogwood seeds sprout in the semi-shade and rich loamy soil at the edge of woods, and native dogwoods usually become one-sided and crooked reaching for the sun.
If you look closely at a mature dogwood in the woods you’ll see it’s in pretty rough shape and wouldn’t look very good in your front lawn. Often the original main trunk died and rotted years ago and only one side (the sunny side) is still surviving. There’s a lesson in this. Dogwoods do best in filtered sun or partial sun, with protection from drying winds. There are exceptions. We have some gorgeous dogwoods in the fields on our farm which we spared when mowing; trees that grew from seed under four-foot high weeds. Some of these are in very poor soil or clay, but none of them are in wet spots.
The most common cause of dogwood death in landscapes is drowning from being planted too deep in heavy soil and then over-watered. Dogwoods really need to dry out between waterings. Pests and diseases usually attack plants that are under stress and leave healthy plants alone. Bark borers and many types of fungus prey on dogwoods. On older dogwoods in trouble we usually see damage to the lower bark, usually from lawn mower injuries that invite borers and girdle the tree.
Field-dug, “ball and burlapped” dogwood trees in the nursery live can for years above ground, with mulch heaped around the root balls to keep them moist. They like sitting above ground because they have good drainage. Often they die within weeks of being sold, because they are planted in clay ground where they can’t drain properly. They start to wilt (a symptom of drowning) and well-meaning homeowners make the mistake of watering still more. We’ve had wilted, half-dead dogwoods returned to us and tossed them on the “dead pile” only to have them revive once they have a chance to dry out.
Most landscapes have less than ideal conditions for dogwoods, but with a little work you can compensate by preparing your soil to be more like the forest floor. Pick a location where there is some protection from the sun and from winter wind. Till a rich mixture of peat moss, Holly-Tone fertilizer and composted pine bark in a six-foot circle, and plant the tree a little high in the ground so it doesn’t drown. Make a mulch circle around the trunk with pine bark so you won’t nick the bark with your lawnmower or trimmer, and expand it each year as your dogwood tree grows.
Fertilizing each year in early spring and again in mid-summer with an acid-rich fertilizer like Holly-Tone will help your dogwood grow rapidly and resist disease. Maintaining the mulch circle around it eliminates competition from lawn grasses, the major cause of slow tree development. You’d be surprised how rapidly dogwood trees grow in commercial nurseries where they are pampered! Growth of two feet per year is common if there’s no competition from turf.
Unfortunately many dogwoods are planted as “memorial trees” and fail to survive. Nothing is more tragic than a sign saying “This tree planted in memory of…” in front of an empty spot of a dead tree. A strong suggestion is to be realistic about the growing conditions you have and consider different flowering trees that are more suitable. There are lots of small-to-medium sized ornamental trees to choose from. An obvious choice is the Chinese dogwood (Cornus Kousa), which is much sturdier than the native dogwood (Cornus florida). We also like Hawthorn, serviceberry, white fringetree, crabapple, tree lilac, ornamental cherry and ornamental pear. All these trees are easier to grow than dogwood.
Steve Boehme is a landscape designer/installer specializing in landscape “makeovers”. “Let’s Grow” is published weekly; column archives are online at www.goodseedfarm.com. For more information call GoodSeed Farm Landscapes at (937) 587-7021.