The tradition of foundation planting evolved from a desire to ease the transition from house to landscape or to disguise masonry and basement windows. Shrubs were the perfect solution. Foundation plantings can present an occasional problem, usually in older homes. The main problems usually result from shrubs or trees that are too close to the house.
On the structural side, several things can occur:
- Some plant roots are quite strong and persistent. Years of growth can cause damage to the house foundation, resulting in a leaky basement.
- Roots absorb a lot of moisture and may result in overly dry soil at the foundation. The soil may pull away from the structure and allow water to seep in.
- As plants mature, the increasing height and width boost the chance of mold or mildew on house siding, causing paint problems.
- Taller plantings decrease the lifetime and effectiveness of gutters and roofing and can interfere with utility lines above and below ground.
Concerning the plants themselves:
- When shrubs are planted too close to the house or each other, drastic pruning is often required to keep growth under control. The natural shape and form of the plant is altered or disfigured.
- Planting too close to the house or other plants decreases air circulation. These plants are also more susceptible to pests and disease.
- If one or more of the above situations exist, it's time to start thinking about replacing or renovating your foundation plantings.
Removing mature plants can be difficult. If you want to transplant a shrub to another spot, a lot of careful digging is required to excavate the root ball without causing damage to the plant or the house. The resulting mass will be extremely heavy, so be prepared with the proper equipment to relocate it. A backhoe or skid-steer is often the only recourse.
After removal, whether you transplant or if the shrub is simply not salvageable, you're faced with a large hole — right beside the house. When you dig out a shrub, have something ready to put in its place. If available, use subsoil (or fill dirt) to fill in the lower portion of deep holes. Fill dirt is less porous than topsoil. Fill to about 8-10-in from the top of the hole, tamp it down and finish filling with a more root-friendly topsoil. If you're installing another plant, make sure you locate it so that it will not be too close to the house or other plants. Do not repeat the same mistake you're trying to fix.
Observe and address drainage problems near the foundation at this time as well. Soil should slope away from the structure. Building codes vary by region, but a 6 inch slope in the first 10 linear feet measured out from the foundation is a relatively common standard.
New homes present an easier project, since installing landscape plants is one of the last steps when a new home is completed. New homeowners have the ability to start with a "blank slate."