Cherry Laurel: Identify and Manage Problems

Cold-hardy in USDA zones 6 to 8. Performs best in moist, well-drained soil with higher organic matter content. Tolerant of a range of soil acidity (pH) levels. Best grown in full sun, but also very tolerant of partial to full shade. Tolerant of salt spray and regular pruning.

Planting sites too close to building exteriors, solid fences, or pavement that reflects heat or sun in hot summer months can cause sunscald and stress. Check the soil drainage and make sure there are no downspouts or other drain outlets adding water to the root zone.

Disease- and insect-resistant plants prevent or help to reduce problems in your landscape. However, no cherry laurel cultivars are currently significantly resistant to insects or diseases. Some varieties might have slightly better resistance to cherry shot hole disease, but these have not been tested locally.
 

Mature size generally ranges from 10 to 15 feet high and about 6 to 12 feet wide, but will vary with the cultivar. Check plant tags for approximate mature size. Dwarf cultivars like ‘Otto Luyken’ grow to approximately 4 feet tall and can reach 6 feet wide. Give plants enough space to mature without relying on pruning to restrict their size.

For container-grown plants, if the roots are root-bound (tangled and circling in the shape of the pot), make several cuts along the outside of the root ball and spread the roots outward so they can establish into the surrounding soil. For balled-and-burlapped (B&B) plants, remove the burlap and any twine or wire cage.

Dig the planting hole just deep enough to accommodate the root ball with the root flare (where roots begin to branch off the stem) level with, or slightly above, ground level. Visit Planting a Tree or Shrub for more details.

Mulch should be laid no thicker than 2 to 3 inches in depth, and keep it several inches away from the base of the plant stems.

Monitor the soil moisture of new plants regularly, and water deeply if it begins to dry out several inches below the surface.

If there is less than 1 inch of rainfall per week, water thoroughly to maintain even soil moisture during dry periods. This is important for plants in their first two years of establishment. Well-established plants should still be watered thoroughly during dry periods. Water at the base of the plants rather than overhead to minimize leaf wetness as much as possible, since moist leaf surfaces can be easier for disease spores to infect.

Fertilize cherry laurel if a laboratory soil test indicates a nutrient deficiency. If planted with an organic soil amendment (such as compost) or with an organic mulch (bark, wood chips, pine needles), most plants should not need additional nutrients from fertilizer.

If desired, prune and shape the shrubs by using hand pruners in early spring (around March). New growth emerging after flowering can be pruned as needed to control size around June. Avoid shearing, which promotes dense outer foliage and bare inner branches, and also increases vulnerability to pests and diseases. Ideally, these shrubs should only be grown where their mature size can be accommodated without relying on regular pruning.

Leaves may turn yellow, brown, and fall off as branch tips die back. Cherry laurel does not tolerate compacted clay soil that drains poorly. In those conditions, excess soil moisture reduces oxygen levels. This can stress or kill roots, resulting in a reduced root system that is unable to function well.

Amending the planting area with compost can improve soil drainage, but cannot reverse root loss that may have already occurred. Roof downspouts or drain pipes that add water to the root zone should be redirected, or another planting site should be chosen. Raised beds can improve drainage, but might not be desirable next to a house foundation.

Broadleaved evergreens are susceptible to drying winter winds, low temperatures, and late frosts or freezes. When the soil surface freezes, moisture becomes unavailable to the plant, similar to drought stress. Leaves dehydrate as the evaporation of water (from wind or dry winter air) occurs faster than the plant can replace it through root absorption. Browning along the leaf edge or surface that results from these conditions is called “winter burn.”

The risk of winter burn can be reduced by planting in locations less exposed to winter winds. Temporary physical barriers, placed about 18 inches from the plants on the windward side and made from a material such as burlap, can also lessen winter wind damage by reducing wind velocity. Water deeply during mild dry spells so there is enough moisture available to the roots before the ground freezes.

Symptoms from stressful site conditions include leaf yellowing or browning, branch dieback, or an entire shrub declining and dying. This may be due to over- or under-watering, a planting location with reflected heat in full sun, and/or poor soil conditions. Poor soil conditions can include compaction, limited root space, too little organic matter, and contamination with excess fertilizer or ice-melt.

Peachtree borer, the larva of a moth, is primarily a pest of cherry, peach, plum, and other related plants (all belonging to the genus Prunus). Cherry laurel is commonly affected, primarily when under stress. Monitor for leaf yellowing, uneven wilting, and branch dieback associated with gummosis (oozing sap), sawdust, and/or frass (insect droppings) at the base of major stems. Lesser peachtree borer looks similar to peachtree borer and is also primarily a pest of Prunus.

Management

There are no conventional insecticides that will kill borer larvae once they are inside the branches. The best control option for home gardeners with only a few plants is to prune out and destroy infested branches. Shrubs can gradually replace lost growth if they remain otherwise healthy.

To discourage borers, keep mulch away from the base of the shrub (do not cover the bark), and lay it no thicker than 2 to 3 inches deep. Do not plant too deeply where the root flare is buried. To minimize stress, keep shrubs watered during dry periods, and avoid injuries, especially with lawnmowers and string trimmers that could cut into bark. 

White prunicola scale (Pseudaulacaspis prunicola) is a type of armored scale insect that feeds on the contents of plant cells. Inspect branch bark for white scale covers; they may look like white fungal growth when abundant.). These waxy body coverings shield the insects from predators and certain pesticides, making them difficult to control. This is a common pest of cherry laurel that causes leaf yellowing, plant decline, and dieback when populations are high. This scale insect can use several other plant species as hosts, but cherry laurels are frequent targets.

Another scale that can feed on cherry laurel is white peach scale (Pseudaulacaspis pentagona). This is a different species from white prunicola scale, but they look practically identical and cause the same kind of plant damage over time. They can occur year-round on the branches of the plant and have a similar life cycle. Management is the same as for white prunicola scale.

Management

The high number of generations per year for prunicola scale means that monitoring and treatment will need to occur several times a year to be effective. Prune out any dead or dying branches because they will not recover; this will also physically remove most of the scale insects. If the infestation is not heavy, use a soft brush to remove the white scale covers from the branches, which will expose the insects to predators and dry them out.

Refer to our general scale management recommendations for both chemical-based and pesticide-free options. When pesticides are warranted, a combination of dormant oil applications and the use of systemic or growth-regulating insecticides is the most effective approach. If you do not wish to use pesticides and are not obtaining good control from manual removal efforts alone, remove and replace the infested plants.

Snowy tree crickets (Oecanthus fultoni) commonly feed on cherry laurel and rhododendron leaves. They have an elongate, narrow, pale green body (about ½ inch, 15 to 18 mm) with orange on the head. The antennae are long and thin, and the long hind legs are muscular for jumping. They generally have one generation a year, and adults are most active from July through August.

Feeding damage becomes apparent in September but does not typically warrant control, since injury to the plant is inconsequential. Chewed leaves appear somewhat ragged or have a scraped appearance. Since snowy tree crickets are also predators, feeding on a variety of insects (mostly sap-suckers like aphids, scale, and psyllids), they are important beneficials that help suppress pests.

Cherry laurel shrubs that are mulched too deeply, or which have excessive weed growth at their base, are susceptible to vole damage. Voles injure stems by chewing into and girdling the base of the shrub, by feeding on roots, and by tunneling through the root system. They cause damage primarily in fall and winter. If removing sources of shelter like excess mulch does not discourage voles from repeatedly gnawing bark, then the use of traps may be needed.

Cherry shot hole disease is a general term that refers to the development of leaf holes as the disease progresses. Infected leaves first develop a reddish-brown spot, some with yellow halos, eventually becoming brown and brittle. As the infected tissue dies and dries out, the spots fall out of the leaf to create a shot-hole pattern that looks like it was caused by a chewing insect. The two pathogens that produce these leaf spot symptoms are the bacterium Xanthomonas pruni and the fungus Blumeriella jaapii. Both diseases are favored by warm, wet spring weather and irrigation that is used frequently or which keeps leaves wet overnight.

The damage is cosmetic and no chemical controls are recommended. If too unsightly, you can prune out heavily-damaged branches and rake-up any fallen foliage. Discard any infected debris to keep the pathogen from spreading. In most cases, the plant will continue to grow and recover. New growth will also hide damaged leaves from the previous season until they eventually fall off with age.