Reply
Respected Contributor
Posts: 4,010
Registered: ‎08-29-2010

Plants too near the foundation?

The former owner of this house loved to garden, and, luckily for me, she planted the perimeter of the house with my favorite flowers. That said, I think I may have to pull out a few I love most -- the lilac bushes. There are two of them planted within inches of the foundation. They have been kept cut back, are only about 4 feet tall now, but based on the size of the trunks, I suspect they have been there quite some time (the house is 20 years old). There is also a burning bush about the same size that is planted just as closely against the house.

I would appreciate any advice from experienced gardeners. Are these plants a hazard to the foundation?

Strive for respect instead of attention. It lasts longer.
Honored Contributor
Posts: 12,882
Registered: ‎03-09-2010

Re: Plants too near the foundation?

Oh that would be hard to cut down a lilac bush!

We have two on either side of our front porch, but our house is raised on blocks so we don't have to worry about any foundation.

Would the root system be that strong to compromise your foundation?

Super Contributor
Posts: 375
Registered: ‎11-22-2011

Re: Plants too near the foundation?

Yes, a lilac bush will ruin your foundation if it is planted too close.

Honored Contributor
Posts: 17,654
Registered: ‎03-09-2010

Re: Plants too near the foundation?

Is the foundation cinder block or poured cement? I think if it was a cinder block foundation it might be a problem.

Always plant at least 3' or more away from foundations when planting shrubs. Figure 20' away for trees.

Always ask at a nursery what is the height and width of the plant at maturity and plant accordingly.

☼The best place to seek God is in a garden. You can dig for him there. GBShaw☼
Honored Contributor
Posts: 24,102
Registered: ‎03-09-2010

Re: Plants too near the foundation?

I certainly wouldn't recommend planting shrubs too close to a house, but I wouldn't be overly concerned about the foundation. A relatively modern house (you said your house was built twenty years ago) is likely to have waterproofing on the exterior of the foundation walls and that waterproofing typically is designed to resist root penetration/damage.

You also have the option to dig up the Lilacs and relocate them. Their proximity to the foundation wall can make digging them up somewhat less burdensome since they're already essentially half contained by the foundation wall. Instead of having to dig a 360 degree circle around the shrub you'd only have to excavate say a 200 or 210 degree arc around the shrub to free it. Now moving a twenty year old Lilac isn't all that easy, but it's doable.

A long term option is to let it move away from the house on its own. Lilacs tend to send up basal shoots and if you get very vigilant over the next twenty or so years and remove those shoots that come up closer to the house and keep those that come up further from the house and remove a third of the old growth closest to the house each year, you'll eventually "grow" the plant away from the house. Over twenty years or so you should be able to selectively prune the plant so that the plant is now a reasonable distance from the foundation wall. It's not a fast solution and you'd need to be vigilant, but over time you should be able to let the plant grow away from the foundation.

I should also point out that in some cases it's beneficial to plant a plant directly against a foundation wall. You can gain an extra zone or two of planting latitude by planting a delicate plant right against a southern foundation wall. I've got a Brugmansia that's been reliably hardy for me because it's planted in a corner between our brick furnace chimney and southern foundation wall. That sheltered area gives it enough protection to survive our New Jersey winters. If your lilac is a bit delicate for the area then it could have been planted there intentionally to keep it alive.

Fly!!! Eagles!!! Fly!!!