By Therese Ciesinski, In the Dirt Editor Photographs by the author
Our native river birch (Betula nigra) is an excellent choice if you want a striking, easy-care tree for moist or wet areas. In nature they grow by streams and rivers, in ravines and flood plains: anywhere there’s fresh water. River birch is native from the eastern U.S. south to Florida, and west to Kansas, and is hardy in USDA Plant Hardiness Zones 4 to 9.
The tree in this photo is about seven or eight years old. I bought it at a native plant sale when it was about 18 inches tall, and grew it in a big pot on my deck for four years until it was large enough to go into the ground.
I planted it next to a stream that overruns its banks every once in a while, but unlike many trees, a river birch will take that in stride. In its three years in the ground, growth has really taken off. The tree is settling into the landscape and looks like it belongs.
River birch has a multi-stemmed, graceful habit. But it’s the wonderful bark that makes the tree stand out. The white, tan, and pinkish bark curls off the trunk like parchment. The tree is resistant to the bronze birch borer that decimates non-native birches, and is deer resistant, too. The yellow fall foliage is attractive, but not knock out brilliant. River birch can reach 40 to 60 feet, taller when conditions are ideal, so give it lots of room.
Site in part shade where the soil is moist. The pH should be slightly acid to neutral. It’s not particular about soil type – sandy, clay, loam, all will do, but having enough moisture is crucial. Keep well watered the first year especially. (The pot I grew it in had a moisture reservoir so it never ran dry.)
Hold in moisture by mulching around the base of the tree after planting – just don’t let the mulch touch the trunk. I used a rubber mulch ring, which kept the soil moist and created a buffer for the lawn mower, and it worked like a charm. I only needed to water once or twice the first year and not at all after that. I took the rubber mulch ring off before the trunk got so big it grew around it.
Varieties include ‘Heritage’, ‘Dura Heat’, a more heat-resistant tree that’s a good choice for the south, and ‘Little King’, a dwarf variety that reaches 10 to 15 feet tall. ‘Summer Cascade’, a weeping variety, tops out at about 15 feet.
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