Plant problems

Why Are My Cornelian Cherry Leaves Curling?

Q: Can I grow cornelian cherry in the UK?

Cornelian cherry (Cornus mas) is one of the most underplanted and rewarding fruiting shrubs for UK gardens. It is fully winter-hardy, long-lived, drought-tolerant once established, and adaptable to a wide range of soils including alkaline and chalk soils where many fruiting plants struggle. It grows slowly into a large, multi-stemmed shrub or small tree reaching 3 to 6 metres over many years. One of its most striking features is its flowering time: the small, bright yellow flowers appear in late winter or early spring (February to March in most UK locations), on bare stems, making it one of the earliest flowering garden plants and a valuable source of early pollen for bees. The bright red, olive-shaped berries ripen in August and September; they have a sour-sweet flavour similar to a very tart cherry and are used in cooking rather than eaten raw in quantity. Cornus mas is available from most specialist nurseries and some garden centres. Two or more plants are beneficial for cross-pollination, though the plant is self-fertile to a degree. It grows well in full sun or partial shade and tolerates exposed positions. No regular pruning is required; mature specimens can be lightly shaped after fruiting.

Q: What do cornelian cherries taste like?

Cornelian cherries (Cornus mas) are small, oblong, bright red berries with a flavour that is intensely tart and sour when underripe, mellowing to a sour-sweet, slightly astringent, cherry-like flavour when fully ripe. The fully ripe berries (which are soft to the touch, like an overripe tomato, and have become deeply red or almost burgundy) are more palatable fresh than the firm, underripe ones; they can be eaten directly from the tree when fully ripe and have a pleasant if sharp flavour. Most culinary use, however, involves cooking the berries with sugar. Cornelian cherry is widely used in Turkish cuisine (the fresh and dried fruit, called kizilcik, appears in jams, liqueurs, and fruit waters), in Eastern European cooking (particularly in Romania and Poland), and in the Middle East. Cornelian cherry jam has a beautiful deep red colour and an intensely tart, complex flavour. Cornelian cherry liqueur (vodka infused with the berries and sweetened) is a traditional preparation in Eastern Europe. The berries are high in vitamin C, anthocyanins, and organic acids. The name 'cornelian cherry' refers to the rich red colour of the berries, which resembles cornelian (carnelian) gemstone.

Q: What is spot anthracnose on cornelian cherry?

Spot anthracnose on cornelian cherry (Cornus mas) is caused by the fungus Elsinoe corni. It produces small, circular spots on the leaves, typically tan or pale brown in the centre with a darker purple-red or reddish-brown margin; the spots may merge in severe infections, causing larger areas of the leaf to die and brown. Affected leaf tissue eventually dries out and may crack, creating a shot-hole effect; the surrounding leaf tissue curls and distorts. In a wet summer the disease can spread rapidly and cause significant premature leaf drop, which weakens the plant but rarely kills it. Spot anthracnose is different from dogwood anthracnose (Discula destructiva), a more serious disease that can kill branches and entire trees; dogwood anthracnose is not currently widespread in the UK but is established in parts of the United States where it has caused significant losses in woodland dogwoods. Control of spot anthracnose on cornelian cherry involves collecting and destroying fallen leaves, improving air circulation, and applying copper-based fungicide in early spring. Established cornelian cherry plants generally tolerate moderate spot anthracnose without permanent damage.

Cornelian cherry (Cornus mas) is a large, slow-growing shrub or small tree from central and southern Europe with bright yellow flowers in February and March that appear before most other garden plants have stirred. In late summer and autumn it produces small, bright red, intensely sour-sweet berries used in Turkish cuisine, Eastern European cooking, and for liqueurs and jams. It is one of the hardiest and most adaptable fruiting shrubs for UK gardens, tolerating alkaline soils and exposed positions. Problems are rare; when the leaves curl, drought stress or a wet-summer fungal disease is usually responsible.

Drought stress

Drought stress is the most common cause of leaf curl on cornelian cherry in UK gardens, particularly on plants that have not yet fully established their root systems (typically in the first two to four years after planting). The leaf margins brown and curl inward in response to water deficit; in severe drought, the whole leaf wilts and droops before curling. Established cornelian cherry is considerably more drought-tolerant than most fruiting shrubs and can withstand prolonged dry periods without serious damage, but young plants do not yet have the root depth to access moisture reserves in dry summers.

What to do

Water young plants thoroughly (10 to 20 litres) once or twice a week during dry periods in the first two to four years. Apply a deep mulch of bark or wood chip over the root zone in spring to retain moisture. Established plants in ordinary UK garden soil rarely need supplementary watering; water during droughts of more than 3 weeks without significant rainfall. Plants in containers need regular watering throughout the growing season.

Spot anthracnose

Spot anthracnose (Elsinoe corni) is a fungal disease of Cornus species that produces small, circular, tan-centred spots with dark reddish-purple margins on the leaves. In a wet UK summer, the spots multiply and coalesce; affected tissue dries and cracks (creating a shot-hole effect), and the surrounding leaf curls and may drop prematurely. Severe infections can cause significant defoliation and weaken the plant, but established cornelian cherry tolerates the disease without permanent damage. The disease overwinters on fallen leaves and infected wood; autumn hygiene reduces the following year's infection.

What to do

Collect and destroy fallen leaves in autumn. Apply a copper-based fungicide spray in early spring as the new leaves emerge, and repeat every 14 days during prolonged wet periods. Improve air circulation by pruning out crossing or congested branches. Avoid overhead watering that keeps the foliage wet.

Aphids

Aphids can colonise the young shoot tips of cornelian cherry in spring, causing the young leaves to curl and distort; the damage is usually minor and self-limiting as natural predators establish on the colony. Several aphid species, including the dogwood aphid (Anoecia corni) and general garden aphids, may be involved; the dogwood aphid is black and often forms conspicuous colonies on the undersides of the leaves. The damage on cornelian cherry is rarely as severe as on more susceptible plants such as blackcurrant or apple.

What to do

Check the shoot tips and leaf undersides in spring. A strong jet of water from a hose can dislodge aphid colonies without chemicals. Apply insecticidal soap or neem oil if populations are heavy. In most cases, natural predator control is sufficient and intervention is not needed; the vigorous growth of cornelian cherry allows it to outgrow moderate aphid damage.

Frequently asked questions

Why are my cornelian cherry leaves curling?

Cornelian cherry (Cornus mas) leaves curl most commonly in the UK because of drought stress, spot anthracnose (Elsinoe corni), or aphid infestation. Cornus mas is generally hardy and problem-free; drought stress causes marginal browning and inward leaf curl, particularly on plants in their first few years. Spot anthracnose causes tan spots with dark margins that spread in wet summers, with the surrounding leaf curling and dropping. Aphids occasionally colonise the young growth, causing leaf curl at the shoot tips.

Can I grow cornelian cherry in the UK?

Cornelian cherry (Cornus mas) is one of the most adaptable and underplanted fruiting shrubs for UK gardens. Fully winter-hardy, drought-tolerant once established, and adaptable to alkaline and chalk soils. It grows slowly to 3 to 6 metres and flowers with bright yellow blooms in February to March on bare stems. The bright red berries ripen in August and September. No regular pruning is required; self-fertile but benefits from a second plant for cross-pollination.

What do cornelian cherries taste like?

Cornelian cherries are intensely tart and sour when underripe, mellowing to sour-sweet and slightly astringent when fully ripe (soft to the touch, deeply red). Most culinary use involves cooking with sugar: the jam has a beautiful deep red colour and complex tart flavour. Widely used in Turkish cuisine (kizilcik), Eastern European cooking, and for liqueurs. High in vitamin C and anthocyanins. The name refers to the berries' resemblance to cornelian (carnelian) gemstone.

What is spot anthracnose on cornelian cherry?

Spot anthracnose (Elsinoe corni) causes small, circular, tan-centred spots with dark reddish-purple margins on cornelian cherry leaves. In wet summers, spots multiply and coalesce; affected tissue dries, cracks (shot-hole effect), and the leaf curls and drops. Established plants tolerate the disease without permanent damage. Control by collecting fallen leaves in autumn, applying copper-based fungicide in early spring, and improving air circulation. It is distinct from the more serious dogwood anthracnose (Discula destructiva), not currently widespread in the UK.