Tips on Proper Care of Genus Ilex Opaca

Moisture

• In its native environment, holly lives in wooded environments with moist, well-draining soil enriched by leaves, pine needles and other organic matter. Replicate this environment by watering regularly, especially during warm, dry weather when natural rainfall is less than 1 inch per week. Water deeply, providing 1 to 3 inches of water, as deep watering encourages long, healthy roots and a strong plant able to resist pests and disease. Let the soil dry slightly between waterings because soggy soil can cause rot and diseases caused by excess humidity. A 2-inch layer of mulch, such as pine needles or bark chips, conserves moisture and helps weeds in check. Extend the mulch to the drip line, which is the point where water drips from the outermost branches.

Feeding

• American holly is a light feeder that benefits from a single application of fertilizer every spring. While an annual dose of fertilizer promotes healthy growth and shiny green foliage, too much makes the tree weak and more prone to disease. Use a slow-release fertilizer formulated for acid-loving plants, such as a 4-3-4, which provides the right blend of nutrients and helps keep soil pH in the right range. Use 1 cup of dry fertilizer for every 1 foot of branch spread. Increase the amount to 2 cups of fertilizer for every 1 foot of branch spread if the spread of the plant is more than 3 feet. Read the label on the product you buy because instructions vary.

Pruning

• American holly has a naturally pyramidal shape. To maintain this shape, prune to keep the base of the plant wider than the top, which also allows more air and light to reach the lower parts of the tree. Winter is the best time to prune American holly, as the plant is dormant. Prune around the winter holidays and bring the clippings indoors to use as decorations. Remove branches that rub or cross other branches, making each cut at a branch union -- the angle where two branches join. You can prune the tree lightly any time of year by trimming the ends of branches to a node, which is a small bump where a leaf or bud grows from the stem. Make sure you trim to shape the tree and not to control the size, because trimming stimulates new growth and creates the need for more pruning.

Pests

• Encourage beneficial insects to come to your garden, because insects, including lady beetles, lace wings and parasitic wasps, feed on harmful pests such as aphids, scale insects and leafminers. Avoid pesticides if you notice pests on your plant. Instead, use an insecticidal soap spray. Soap spray kills only on contact and has no residual effect, making it less harmful to beneficial insects. Spray the tree every four to seven days, as needed, using a solution mixed at a rate of 2 1/2 to 10 tablespoons per 1 gallon of water, depending on the severity of the infestation. You can also purchase pre-mixed, ready-to-use insecticidal soap. Check the product's label, as instructions vary by brand.