Soil: The Draining and Freezing in Winter

Why drainage is important for plants in the winter.

Kniphofia uvaria 'Pfitzer’s Hybrid Mix'
Item # 96491 		Kniphofia uvaria 'Hybrid Mix'
Red Hot Poker

each $7.99
3 to 6 plants $7.79
7 or more $7.59
Sisyrinchium augustifolium 'Lucerne'
Item # 91850 		Sisyrinchium augustifolium 'Lucerne'
'Lucerne' Blue-eyed Grass

each $7.99
3 to 6 plants $7.79
7 or more $7.59
  • Topic: Soil
  • Author: Cindy Bellinger
  • Keywords: winter, water, drainage, soil, Soil
  • Date: November 2002

© All articles are copyrighted by High Country Gardens. Republication is prohibited without Permission.

It looks like we might be in for a wet winter this time around. Let’s hope so. But when it comes to our gardens, the added moisture can also be an added problem. More water can mean more freezing, and more freezing means potential damage to plants.

Now that you’ve created wells around plants and trees to keep the water in, you need to make sure the water can also get out. Both surface and subsurface drainage is essential to plants for winter survival. If water remains in the soil, freezing can occur. When soil repeatedly freezes then thaws, heaving takes place—that pushing and up ending of soil.

Heaved plants can fracture taproots as well as lateral roots. This heaving activity can also result in elevated crowns, quickly drying out a plant. Plants that endure all this will either die or be severely stunted.

But don’t despair. It’s not all gloomy. Mulching plants will usually take care of the inconsistencies in temperature. And if you’re even a half-way serious gardener, you’ve probably been adding amendments to your soil. We have more than our share of clay soil around here. And any organic matter helps drain water because it’s that heavy clay soil that wrecks havoc in a garden. Especially if it’s in a low-lying area. Clay soil retains just about all the water it gets.

Though the rule is to keep watering during the winter, excessively wet soil or sites with standing water can decrease winter hardiness in some plants. They will wilt even when surrounded by standing water because water-laden roots are unable to gather water, which therefore starves the plant for oxygen and other nutrients.

One solution to tough drainage problems is burming the planting area. That is, making and planting on a raised hill so water will naturally run off. Another solution for areas with standing water is to install a drain line. A perforated 3-inch plastic drainpipe installed 12-15 inches deep works well, but make sure it’s on an even slope so mud doesn’t clog up the low spots in the pipe.

The best time to improve drainage for trees, shrubs, perennials and bulbs is at the time of planting. The planting hole should be three to five times the width of the root ball and about the same depth. Organic matter, such as compost and other soil amendments should be mixed into the soil.

But if you want to be really clever, another solution to low-lying, water gathering areas is to plant 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.

David 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.

Other plants that enjoy boggy soil include Red Twig Dogwood, Blue Arctic Willow and Yellow Groove Bamboo.

David says: “Use the natural marshy places to your best advantage.”

Freezing is the most common cause of winter damage in a garden, and the plants most susceptible to heaving are newly planted ones because their roots aren’t sufficiently anchored. Again, mulching will help. And if they do pop out, just push them back in.

If we do get a wet winter this year, a little forethought along with some careful plant selection can get most gardens through fairly well.