Q: What trees can thrive in prolongued wet soil?
Monday, January 4, 2016
I live in Pennsylvania and have a very moist area of approximately 30' x 50' in my yard. I was wondering what the best type of tree would be to plant in this area, and how many, to help with the moisture. Animals and birds are very welcome, so fruit-bearing trees would work.
A: Wet soils are not easy to deal with. Planting trees may help, but much depends on soil conditions, such as depth to the impermeable layer, soil nutrient content, and other factors. Some trees can tolerate wet soil for prolonged periods, but they may not really thrive, and they may not actually remove much of the water if it is being constantly replenished.
The first step is to figure out why the area is wet and learn if there is some way to help with drainage. If the problem was created by construction activities, like spreading and compacting subsoils over the surface, it may be possible to break up the hard layer that prevents waste from draining down into the soil, or perhaps a drainage swale, ditch, or pipes can be installed.
As to planting trees, you will need to plant species that tolerate and thrive in wet conditions. The best among these is baldcypress (Taxodium disticum). It is an evergreen tree that lives in swamps, often spending most of its life in standing water. It does grow well under dryer conditions, so it's all right if the yard dries up from time to time. Other good choices include black gum or tupelo (Nyssa sylvatica) and most of the willow trees (Salix spp.) The tupelo is a great tree in moist areas but doesn't like standing water. Plant it around the edges of the wet area. Willows are fast-growing trees, known for absorbing a lot of water. They also do not like standing water, especially in the summer months, but do well along the edges of ponds and streams. They are not as long-lived and can present higher than usual risks of failure when they get large, after 30 or 40 years. These should be planted away from buildings and high use areas. Sycamore (Platanus occidentalis) and London planetree (Platanus x acerifolia) may also be good choices. They tolerate wet soil, except during summer months; grow quickly; and are long-lived, often living 200 to 300 years.
Check online for descriptions of these trees to see what matches your needs. Contact a qualified local arborist or Consulting Arborist for more advice.
Responder: Russ Carlson, RCA #354, Bear, DE