Planting Boxwoods over French Drain

by Jerry Johnston
(Dallas-Ft Worth, TX)

I am a swimming pool contractor. We recently installed a french drain next to a swimming pool. The purpose of the drain was to catch water that drains from property that is higher then where the pool is located. Once we installed the french drain we planted boxwood plants over the french drain. The Boxwoods are doing well even with the drought we have experienced in Texas this summer. My question is:

Will the Boxwoods grow well with planting them over the french drain? I have checked with other landscape contractors and they indicate they have planted over french drains with no problems.

Thanks,
Jerry

ANSWER

Hi Jerry,
Just so I understand things accurately so that I can answer your question correctly, a french drain in this situation would be below the ground, wrapped in fabric, and typically have stone placed over it. And it is not that deep. Is this what was done on your project?

See Perforated Pipe

RESPONSE

Yes, the french drain is down about 12" and is covered with pea gravel. Over the pea gravel we have soil and then the 3 gallon boxwoods.

ANSWER

Hi Jerry,
I would not plant the Boxwood over a drain. First of all, I don't like the idea of the drain being covered with plants. The idea of the drain is to let the water percolate down into it. Actually, most french drains that I am familiar with (for landscaping, not for house foundations) are not that deep. You WANT the water to get down into the drain. So plants prevent this, and if it is a very wet area, they may not soak up the water fast enough to prevent water collecting in that area. I have a french drain. It is only a few inches from the surface and is covered only with gravel.

Also, I don't believe Boxwood like very wet conditions. I don't know how much soil you have over the pea gravel, but plants usually have deep soil beneath them, not gravel. The gravel may help the drainage, and may even help the plants from getting water logged, but I don't think it is best for the plants.

What you might consider if appropriate and if you have the room is moving them back so that their roots are not over the drain. You are in essence making a bed where the drain is, and the Boxwood are then behind the drain area. You can either just leave the area over the drain mulched or plant annuals or a groundcover, or better yet, just leave pea gravel on top. You can divide the pea gravel area fromt the planted area with some steel edging, so that the area stays neat.

Susan