According to the Weekend Gardener website, a wet area is defined as an area where there is standing water. In wet areas, drainage is poor and generally occurs at a rate less than one inch per hour. Wet areas may also be subject to large amounts of run-off from higher elevations, causing water to collect at a rate the soil is unable to handle.
Effects on Evergreens
Wet areas are difficult to landscape because even the hardiest of plants suffer. As the water content in an area rises and does not properly drain, the oxygen levels in the soil plummet. According to the University of Minnesota, evergreen trees are some of the hardiest plants available and generally survive when other plants suffer. However, wet soil can be detrimental to the evergreens. Signs of suffering trees include smaller needles, decreased growth and even death.
Cope with wet areas by increasing drainage. Some recommended ideas are installing drain tiles or pipes, according to the Weekend Gardener. This helps draw water away from the trees and improve the chances that they properly survive.
Gypsite is a product that may also help improve the drainage in wet areas. Gypsite helps open up the pores of the soil and drain water away almost instantly, according to the Weekend Gardener. After applying gypsite, allow the area to dry and test the soil. Clay soil generally accompanies wet areas and is poor soil for properly growing evergreens. Add organic mulch or compost to help improve soil conditions.
Evergreens for Wet Areas
Even with new drainage techniques, some areas will still be wet. The University of Minnesota and the Weekend Gardener recommend several types of evergreens that are more tolerant of wet soil than most varieties. They also feature root structures that consume large amounts of water, helping trees grow and drain soil. In wet areas, consider planting American holly, Southern magnolias, American arborvitae, balsam firs, black spruce or Austrian pine.