No, fertilizing heather is not recommended. Heaths and heathers like a lean soil. A little bit of 5-5-5 (tsp) probably won't do damage, but it's not a practice to maintain. More important are soil conditions and, before new growth begins, a light shearing of the plants to induce fuller growth. More info is available in Rock Spray Nursery's online catalog or in that from heathsandheathers.com.

Here is a link that might be useful: Rock Spray

A light application of fertilizer formulated for acid lovers in spring as new growth begins is not unreasonable. Otherwise, proper siting and correct soil conditions are overriding factors in the successful growing of these plants.

I'm not sure what the fertilizer ratio is for acid-loving plants (I used 5-5-5), but I'm not sure I even used a 1/2 of a teaspoon per plant, so that's good, at least...

Thanks for your help!