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Select trees, plants that won't damage foundation

With spring just a few weeks away, Wisconsin gardeners are already planning how they'll spruce up their yards this year.  As you make your plans, be sure to consider keeping your foundation safe as you select plants and trees, and decide where to plant them.

When it comes to trees, consider how tall they'll get, how wide they grow, and where you'll need to put them to cast their shade, advises Jim, a blogger for Your Garden Sanctuary.  Jim works in the design/build department of southern Wisconsin nursery/landscaping company. He's also been a horticulturist and aesthetic pruner at a top quality Japanese Garden, as well as a freelance garden consultant.Redbud trees are good for planting near homes and won't damage foundations. Photo by BETTY, Wikimedia Commons.

To keep your house cool, plan to shade the late afternoon sun, which comes in at a lower angle. "In order to get the most useful shade on a house, you should place a shade tree about 20 feet from the house," Jim says.

If you plant trees too close to your home, three main problems can arise:

  1. Mechanical damage from roots exerting pressure on the foundation.
  2. Fluctuations in soil moisture, causing soil to expand and contract and put pressure on the foundation.
  3. Hazards such as branches falling on the house.

Some trees have roots that grow so aggressively that they shouldn't be planted even 20 feet or more from your home, according to Jim. They include:

  • Poplars, Cottonwoods and Aspens (Populus): These seek out water with their wide-spreading root systems. They are one of the worst to plant near homes.
  • Silver Maple (Acer saccharinum): Shallow and dense roots can invade foundations.
  • Norway Maple (Acer platanoides): Because their roots are near the surface, these trees are notorious for lifting and shifting concrete.
  • Willows (Salix spp.): Willow roots run deep to anchor trees and seek moisture. They will invade your  home, septic and water systems.
  • American Elm (Ulmus americana):  American Elms have deep roots that often clog sewer lines and drains. These should also be kept well away from anything related to water.

Two others to avoid near your foundation: Black Alder (Alnus glutinosa) and Black Locust (Robinia pseudoacacia).

So now that we know what you shouldn't plant, what plants are recommended for locations near foundations? Nikki Phipps at GardeningKnowHow.com makes these suggestions.

  • Small ornamental trees, such as dogwood, redbud, Japanese map, crepe myrtle and star magnolia.
  • Vining plants for ground covers, such as liriope, ivy, creeping juniper, periwinkle and sweet woodruff. Keep these at least 12 inches from the foundation.
  • Low-growing shrubs like yew, juniper, boxwood and holly. Allow at least 3 feet between plants to prevent overcrowding.
  • Tree-form evergreen shrubs such as wax myrtle, ligustrum or cherry laurel are good for small areas. Keep these at least 5 feet from the house.