If your heather has root rot, the stems will wilt as though they are drought-stressed and develop soft rotten spots. Heather plants are rarely salvageable when they develop rot and should be replaced with a new, healthy plant.
Use a soil pH test kit to test the soil. The kit can be purchased at your local garden center. To determine the soil’s pH, dig 4 inches deep into the soil to get a good test sample. Avoid touching the soil as contact with your skin can change the soil pH. Let the soil sample dry before testing it. Pour the sample into a clean glass container, add distilled water and the chemicals that are in the test kit. Stir or shake the mixture vigorously and let it sit until the soil settles to the bottom. Compare the color of the liquid to the test strip to determine the soil pH.
Sandy soil will require about 1 ¼ pounds of lime per 25 square feet to bring the pH up from 5. 5 to 6. 5 or about 1/3 pound of iron sulfate to adjust the pH down from 7. 5 to 6. 5. Mix the lime or iron sulfate into the top 6 inches of soil thoroughly before planting the heather. If the heather has already been planted, gently work the lime or iron sulfate into the top 1 inch of soil, being careful not to disturb the plant’s roots. Before planting the heather, a 3- to 6-inch layer of sphagnum peat moss, well-aged cow manure, pine bark humus, leaf mold or compost should be mixed into the top 8 to 10 inches of soil thoroughly with a tiller. If the heather has already been planted, spread a depth of 2-inches of organic matter around the plant and mix it into the top inch of soil. Spread a 1-inch depth of sphagnum peat moss over the soil around the heather to help keep the area moist.
Push the rod into the soil until it meets some resistance. Grasp the rod just above the soil when it hits dry dirt, pull the rod out and measure the depth of the wet soil.
Pour enough water over the soil around the heather to moisten it to a depth of 6 inches. You can measure the depth with the thin metal rod.
Be sure to rake up all of the trimmings and remove them from the garden to reduce the possibility for fungal or bacterial disease like stem or root rot.
