Escallonia Leaves Curling

Frost damage

Frost is the most significant cause of leaf damage and curling on escallonia in the UK, and the factor that most limits where these plants can be grown successfully. Escallonia is native to South America, principally Chile and adjacent regions, and its evergreen foliage is vulnerable to the combination of frost and cold drying winds that characterises British winters in inland and northern positions. The glossy, small leaves brown, curl, and collapse after exposure to sharp frosts, and in severe winters the damage can extend through all the foliage and into the stems, killing the plant back to the crown or below. In mild coastal gardens and sheltered urban positions in southern England, escallonia is essentially trouble-free through winter; in colder, more exposed positions, frost damage ranging from leaf browning to total above-ground death is common after hard winters. The most widely grown hybrid cultivars including Escallonia Apple Blossom, Donard Seedling, and Iveyi are more cold-tolerant than the straight Escallonia macrantha species, which is best restricted to mild coastal gardens in the UK.

Cut back frost-damaged escallonia in late spring after the risk of further frost has passed. Scrape stems at intervals from the tips downward to identify where green, living tissue resumes and cut back to that point. Established escallonia with living roots and crown tissue regenerates strongly from the base even after losing all top growth, and cutting back to the living wood rather than removing the plant entirely is nearly always the right response. Protect newly planted escallonia and tender cultivars with horticultural fleece during cold snaps in their first few years. Planting against a south or west-facing wall or fence provides significantly better frost protection than an open position, both through the structural shelter the wall provides against cold winds and the heat the wall stores and radiates through cold nights. In exposed or inland gardens, choosing the hardiest available cultivars rather than the ornamentally attractive but tender Escallonia macrantha types reduces the frost risk substantially.

Scale insects

Scale insects are the most common pest on escallonia, particularly on wall-trained plants in sheltered positions where the warm microclimate accelerates scale population development and natural predator populations are lower than in open garden settings. Several species colonise escallonia, with brown soft scale (Coccus hesperidum) and cushion scale (Pulvinaria species) the most frequently encountered. The scales attach firmly to stems and to the undersides of the glossy leaves, feeding continuously on plant sap. The honeydew they produce as a waste product falls onto the leaf surfaces below and provides the growth medium for black sooty mould fungi that rapidly colonise the affected leaves. Escallonia's naturally glossy foliage, which is one of its ornamental features, becomes visibly dull and blackened under heavy sooty mould deposits, and the leaves may curl and drop prematurely as the infestation reduces photosynthesis. Stems with heavy scale infestations take on a rough, encrusted appearance from the bodies of the scale insects.

Treat scale insects in late spring or early summer when the mobile juvenile crawlers are hatching from egg masses and are vulnerable to contact sprays before they settle and develop their protective covering. A fatty acid spray, neem oil solution, or a plant oil-based insecticide applied thoroughly to all stem and leaf surfaces at this timing is the most effective treatment. The glossy leaves of escallonia hold spray well, which improves contact with crawlers. Repeat the application at ten to fourteen day intervals for two applications to catch crawlers that hatched after the first treatment. For established infestations of adult scale, physically wiping the scales off stems with a damp cloth removes many individuals and reduces the population before spraying for crawlers. Keep plants growing vigorously, as healthy escallonia tolerates and recovers from moderate scale infestations more readily than stressed plants.

Drought and leaf scorch

Drought stress causes escallonia leaves to curl inward, lose their characteristic gloss, and develop a slightly dull, greyish-green tone. The small, leathery, glossy leaves of escallonia provide good protection against moisture loss compared with the thin foliage of many other evergreens, but wall-planted escallonia growing in the rain shadow of a building is particularly exposed to drought because the wall base receives significantly less natural rainfall than an open position and the wall itself generates heat that increases evapotranspiration. Leaf scorch, producing brown tips and margins on the leaves, occurs when the rate of moisture loss from the leaf surface exceeds the rate at which the roots can supply water, particularly in hot, windy conditions. Newly planted escallonia in its first summer is most at risk, before its root system has spread to access moisture across a wider area of soil.

Water newly planted escallonia consistently through its first two to three growing seasons. Once established, escallonia is relatively drought-tolerant but wall-planted specimens benefit from supplementary watering during prolonged dry spells throughout their life. Apply a generous mulch annually at the base of the plant, keeping it away from the stem base, to retain soil moisture and reduce the temperature extremes of the soil that most stress the roots. Escallonia's naturally glossy foliage means that drought-related leaf curl is often less visually prominent than on larger-leaved shrubs, but the plant's growth and flowering capacity are reduced by water stress even when the visual symptoms are mild.

Phytophthora root rot

Phytophthora root rot occasionally kills escallonia planted in poorly drained or waterlogged soil. The water mould attacks the feeder roots and spreads into the crown, causing the root system to rot progressively. Above-ground symptoms develop as the plant's ability to take up water and nutrients declines: the leaves wilt, curl, and lose their colour, and individual stems begin to die back before the whole plant collapses. The speed of collapse once symptoms appear, often within weeks, is characteristic of phytophthora. Escallonia planted in heavy clay without drainage improvement or in low-lying positions where water accumulates is most at risk. The risk is lower than for highly susceptible genera such as ceanothus, but escallonia in genuinely waterlogged soil can succumb to phytophthora particularly in wet winters.

Plant escallonia in well-drained to moderately moist soil. In heavy clay, incorporate grit and organic matter and plant at or slightly above the surrounding soil level to ensure the crown is not in contact with standing water. Avoid planting in positions where water is visible on the surface for extended periods after rain. If an established plant shows sudden wilting and collapse in a poorly drained position, phytophthora is the most likely cause; remove the plant including roots and improve drainage before replanting with a different species.

Honey fungus

Honey fungus (Armillaria species) occasionally affects escallonia, spreading from infected root systems of dead trees or large shrubs through the soil on dark, bootlace-like rhizomorphs. An escallonia affected by honey fungus shows progressive decline in growth and vigour, with leaves yellowing and curling and stems dying back over one or two seasons, ending in plant death. The diagnostic white mycelium with a distinct mushroom smell beneath the bark at the stem base and soil level, and the possibility of honey-coloured toadstools appearing in autumn, distinguish honey fungus from other causes of decline. Escallonia in a garden that previously contained old tree stumps or root systems is at greater risk.

There is no chemical control for honey fungus. Remove affected plants including as much of the root system as possible. Physical barriers of heavy-duty polythene installed vertically in the soil around affected areas limit rhizomorph spread. Replanting with a honey fungus-resistant species in the affected area reduces the risk of further losses from the same rhizomorph network. Escallonia is moderately susceptible and should not be replanted in an area with known honey fungus activity without addressing the source of infection first.

Frequently asked questions

Why are my escallonia leaves curling?

Frost damage is the most common cause of leaf curling and browning on escallonia in the UK, particularly in cold winters or exposed positions. Scale insects cause leaf curl, sticky honeydew deposits, and sooty mould on the glossy foliage. Drought stress causes the small, glossy leaves to curl inward and lose their sheen in hot, dry conditions.

Why are my escallonia leaves turning brown?

Brown leaves on escallonia most often indicate frost damage, where the evergreen foliage is damaged or killed by cold temperatures in winter. Brown tips and margins in summer indicate drought stress or leaf scorch in hot, exposed conditions. Scale insect infestations produce black sooty mould on the leaf surfaces that appears as browning or blackening of the normally glossy leaves.

Is escallonia frost hardy?

Escallonia hardiness varies by species and cultivar. Escallonia rubra and most common hybrid cultivars are moderately hardy, tolerating temperatures down to about minus ten degrees Celsius in sheltered positions. They are reliably hardy in coastal and southern UK gardens but may suffer significant dieback in severe winters inland or in exposed northern positions. Escallonia macrantha is less hardy than the hybrid varieties and is best suited to mild coastal gardens.

Does escallonia get scale insects?

Yes, escallonia is susceptible to scale insects, particularly in sheltered wall positions. Scale insects attach to the stems and undersides of the glossy leaves and feed on plant sap, producing sticky honeydew that develops into black sooty mould. Treat in late spring when the crawler stage is active with a fatty acid or neem oil spray, and physically remove scale from accessible stems with a damp cloth.