Plants that like Wet Soil

If you have low-lying areas that tend to gather water, choose plants that love marshy environments. Let's include a few plants that actually like wet soil.

  • Topic: Soil
  • Author: Cindy Bellinger
  • Keywords: perennials, moisture, moist, wet, soil,
  • Date: November 2005

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In continuing with this series on soil drainage, it only makes sense to include a few plants that actually like wet soil.

If you have low-lying areas that tend to gather water, choose plants that love marshy environments. David Salman, President of Santa Fe Greenhouses, suggests using Camassia leichtlinii ‘Blue Danube’, a native bulb from the Pacific Northwest. “It loves wet clay,” he says.

He also recommends Kniphofia uvaria ‘Pfitzer’s Hybrid Mix’ or Red Hot Poker, a plant that grows in the marshes of South Africa. Also Blue-Eyed Grass (Sisyrinchium augustifolium ‘Lucerne’) likes swampy conditions as well.

The Plants Will Tell You

Sometimes sites aren’t obvious as to water drainage so take a look at the plants. On poorly drained sites they may not die, but instead plants might show chronic symptoms associated with root loss. These include yellowing of leaves (chlorosis), defoliation, marginal scorching, dwarfed foliage, and dieback. Trees and shrubs experiencing root decline from excess water are also more susceptible to attack and invasion by secondary diseases and insects.

The Gas Exchange in Soil

In addition to water, soil must contain oxygen. Roots absorb this oxygen and expel carbon dioxide back into the soil in their normal process of respiration. This is done in spaces between soil particles called pores, which are not filled with water. Without this normal exchange of gases, carbon dioxide builds up and oxygen is less available, so roots die.

A good well-drained soil has about half its volume in actual soil solids, and the other half as air space. Of this air space, about half is made up of large spaces and one half small spaces. Under normal periods of irrigation or rainfall the small pores spaces are able to hold water, the larger ones release the water to the pull of gravity and refill with air.

More Plants

So you don’t have to always find ways to drain low areas and David says, “Use the natural marshy places to your best advantage.” Other plants that enjoy those boggy environments include:

  • Red Twig Dogwood
  • Blue Arctic Willow
  • Yellow Groove Bamboo.

A Word of Caution

During construction, excavating or landscaping, the slope or grade of a surface may be changed. Only a few feet of extra soil added to the surface will adversely affect trees. The added soil interferes with the exchange of gases, particularly oxygen, between the roots of trees and the air above the soil surface.

Protect older established trees when carrying out a major grade change. The construction of large “wells” that coincide with the drip line (the furthest extent of the branches) will maintain the existing grade around these trees. Similarly, if soil is to be removed, retain the soil around existing trees through the use of a retaining wall extending to the drip line.

Water is essential for plant growth, but too much can result in the death of plants. Another way to work with soil drainage, is to consider the soil and water needs of plants you’re putting into your garden. More on that another time.