Fertilizing Holly Bushes
Gardeners have lots of options when choosing a holly plant fertilizer. Compost or well-rotted livestock manure makes excellent (and often free) slow-release fertilizers that continue to feed the plant throughout the season. A complete fertilizer that contains eight to ten percent nitrogen is another good choice. The first number of the three-number ratio on the fertilizer bag tells you the percentage of nitrogen. For example, a fertilizer ratio of 10-20-20 contains 10 percent nitrogen. Holly bushes like soil with a pH between 5.0 and 6.0, and some fertilizers can acidify the soil while fertilizing holly bushes. Fertilizers formulated for broad-leaved evergreens (such as azaleas, rhododendrons, and camellias) work well for hollies, too. Some manufactures produce fertilizers designed specifically for hollies. Holly-tone is a good example of this type of product.
How to Fertilize Holly
Pull back the mulch and apply the fertilizer directly to the soil around the holly. If you are using a complete fertilizer with a nitrogen content of eight to ten percent, use one-half pound (0.25 kg.) of fertilizer for each half-inch (1 cm.) of trunk diameter. Alternatively, spread three inches (7.5 cm.) of rich compost or two inches (5 cm.) of well-rotted livestock manure over the root zone. The root zone extends about as far as the longest branch. Work the compost or manure into the top inch or two (2.5 or 5 cm.) of soil, taking care not to damage surface roots. When using Holly-tone or an azalea and camellia fertilizer, follow the directions on the container because formulations vary. Holly-tone recommends three cups per inch (1 L per 2.5 cm.) of trunk diameter for trees and one cup per inch (0.25 L per 2.5 cm.) of branch length for shrubs. Replace the mulch and water slowly and deeply after applying the fertilizer. Slow watering allows the fertilizer to sink into the soil rather than running off.
When to Feed Holly Shrubs
The optimum times for holly fertilization are spring and fall. Fertilize in spring just as the shrubs begin to put on new growth. Wait until growth stops for fall fertilization.
