Drainage concerns

Old 03-11-06, 09:14 PM
Thread Starter
Join Date: Jul 2002
Location: Ca
Posts: 756
Received 1 Vote on 1 Post
Drainage concerns

I'm finally at the stage where I'm ready to plant some Peonies (in the fall), Clematis and possibly some Rhododendron. The difficulty I face where I live is the worst clay soil imaginable. For smaller plants this does not really present a problem as I simply add copious amounts of compost to a depth of 12" or so.

For the larger plants, I dug holes as deep as I could (about 3'), put some gravel and gypsum in the bottom and filled the hole with a mix of compost, peat moss and topsoil. This will give the plant the best soil quality possible but experience tels me the hole still will not drain one iota. If the soil becomes saturated into the root zone of the plant they will suffer or die.

Experience with medium size plants tells me that if I'm real careful not to overwater and the plant is not at a low point I may be able to avoid extended periods of soil saturation (rain is rare here in the late spring, summer and early fall). However due to the extreme sensitivity of the plants mentioned to root rot it may be wise to add a raised bed on top of the prep I have already done. Using a treated 2x10" would give another 10" of insurance and the medium sized plants in front of the planter will help disguise it. Anyone have experience with these plants in poor soil?
Old 03-12-06, 07:35 PM
Join Date: Aug 2000
Location: USA
Posts: 15,817
Received 1 Vote on 1 Post
Peonies are typically not too picky about soil, but they would like some organic material and compost in planting holes. With good drainage and a neutral pH soil or only slightly acidid, peonies are good for years. They should be planted away from trees and shrubs where they would have to compete for moisture and nutrients. They do not respond well to transplanting.

Clematis are picky and sometimes difficult to grow. Prepare soil 2 feet deep and about three feet wide. Mix 1/3 of volume of soil with compost to help with aeration and drainage. Clematis prefers pH neutral soil. Most plants prefer full sun while others may suffer from fading blossoms.

Rhododendron and azalea do best in mild, humid climates. They fair best on north or east side of home where not exposed to south and west winds and sun. Filtered sunlight is ideal. Too much shade is not good. Rhododendron and azalea do not do well in heavy soil where roots can not penetrate. Good drainage is necessary. Dig a hole 6 inches deep and fill it with water. If the water has not drained from the hole in four hours, install drainage tile to carry away excess water, or build raised beds at least a foot above ground level. Dig out the bed 18 inches deep and at least 30 inches wide. Plants should be spaced 3to 4 feet apart and at least 18 inches from the edge of the bed. Have soil tested. pH should be acidic at 5 - 5.5. When digging, remove top soil and save, if any, and discard heavy soil. Mix 50 percent ground pine bark, or leaf mold from pine or oak leaves, 25 percent coarse sand and 25 percent topsoil. Prepare bed several weeks in advance to allow pH to change. Recheck pH a year later. Mulch heavily to protect roots, but keep mulch off stems during summer and fall. Use fertilizer for acid-loving plants.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: