GARDEN CAPSULE
The challenge: There’s a low spot in your yard, in the path of the automatic sprinkler. You haven’t had good luck with trees there and are wondering if there’s any that can succeed in periodically wet soil.
The solution: Choose from trees that are native to lowlands or swamps: Bald cypress (Taxodium distichum), red maple (Acer rubrum), cottonwood (Populus deltoides), river birch (Betula nigra), black alder (Alnus glutinosa), weeping willow (Salix alma “Tristis”) or sweet bay magnolia (M. virginiana).
Pluses: Bald cypress turns a beautiful copper color in autumn. The flowers of maples and willows are an early pollen source for bees and other pollinators. The trunk of river birch has peeling bark, providing year-round interest. Cottonwood grows quickly.
Black alder’s summer foliage is glossy-green. Weeping willow forms an attractive, inviting canopy. Sweet bay magnolia has fragrant, white flowers in late spring and tolerates some shade.
Minuses: Except for sweet bay magnolia, the other trees aren’t a good fit for a small yard. Because bald cypress is a deciduous conifer that looks like an evergreen during the growing season, it’s sometimes mistaken for a dying tree when it loses its feathery foliage in autumn.
Cottonwoods, willows and alders are subject to cankers and other diseases. Maples and magnolias are susceptible to verticillium wilt.
All trees, even these, fare better when planted outside the range of an automatic sprinkler.
Sources: Any of the recommended trees should be readily available through your local nursery or garden center.