Good Ground for Azaleas
As you continue your spring planting and transplanting, remember that many popular species perform best in acid soils. Among them are the now-blooming beauties azalea, rhododendron, mountain laurel, andromeda, Japanese hollies, deciduous hollies and blueberries. Oak and sweetgum trees also like acid soils.
The best time to transplant these species is early spring and, even better, fall, when they’ve stopped growing new stems and leaves and are starting to generate and elongate roots.
Pruning is best done just after blooming, but never on new transplants.
Success in transplanting these species can be guaranteed if you follow the following guidelines.
1. Know the Ph of your soil before planting. I rely on A&L Eastern Agricultural Laboratories in Richmond for all of my soil testing. Each soil test should be made from a composite of five or more core samples. Find directions at al-labs-eastern.com.
2. Select a spot where the soil is well drained. None of these species will grow in poorly drained soils.
3. All of these plants — except the trees — are shallow-rooted. The depth of the planting hole should not exceed 90 percent of the height of the root ball. In other words, 10 percent of the root ball should be above grade.
4. Add one-third to one-half compost by volume to the soil you removed when digging the hole. Do not bring in imported soil.
5. Acid soils are generally low in calcium. Incorporate one rounded tablespoon of gypsum (calcium sulfate) to the compost-amended soil and mix thoroughly.
6. If roots are tightly meshed around the outside edge of the root-ball after you remove it form the container, take a sharp knife and slash the roots at least one inch deep from top to the bottom of the root ball at three- to four-inch intervals around the entire root ball. Cutting the roots hastens root growth into the new soil.
7. Water the plant well, even if it is raining, and repeat watering at four- to five-day intervals. Never water plants daily.
Is Your Soil Well Drained?
To test drainage, dig a hole about a foot deep. Fill with water. Fill it again (some sources say immediately; some say the next day).
Measure the depth with a ruler. In 15 minutes, measure again. How many inches has it dropped? Multiply by four to determine drainage per hour.
Below one inch is poor drainage; over six is excessive. Anything in between is good drainage.
Ask Dr. Gouin your questions at [email protected]. Please include your name and address.