Plant problems

Why Are My Buffaloberry Leaves Curling?

Q: Why are my buffaloberry leaves curling?

Buffaloberry (Shepherdia argentea, silver buffaloberry) or russet buffaloberry (Shepherdia canadensis) leaves curl most commonly in UK cultivation because of drought stress, aphid infestation, or leaf rust (Puccinia species). Buffaloberry is a hardy, drought-tolerant, nitrogen-fixing shrub from North American prairies, dry plains, and open woodland; in its native habitat it grows in hot, dry conditions with thin, alkaline, or nutrient-poor soils. In the UK it requires very different management from most garden shrubs and does best in full sun with very well-drained, low-fertility soil. Despite its drought tolerance once established, newly planted buffaloberry in the UK can suffer drought stress because the UK's more humid climate means the plant may initially develop a shallower root system than in its native dry environment. Aphids can colonise the tender young shoot tips in spring, causing them to curl. Leaf rust (Puccinia species) can cause small, yellow-orange pustules on the leaf undersides and corresponding pale spots on the upper surface; severely affected leaves may curl, yellow, and drop. Waterlogged soil causes root rot and sudden collapse of the plant, which looks different from curl but is a common cause of decline in UK conditions where the plant is sometimes grown in soil that is too wet.

Q: What is buffaloberry and can I grow it in the UK?

Buffaloberry is the common name for Shepherdia argentea (silver buffaloberry) and Shepherdia canadensis (russet buffaloberry or soapberry), two species of nitrogen-fixing shrubs from North America. Silver buffaloberry (Shepherdia argentea) is a thorny shrub or small tree to 4 metres with distinctive silver-grey leaves covered in fine silvery scales (similar in appearance to the related oleaster, Elaeagnus); it produces small, bright red to orange-yellow berries in late summer with an extremely tart, acidic flavour. Russet buffaloberry (Shepherdia canadensis) is smaller and thornless, producing orange-red berries. Both species are members of the Elaeagnaceae family and fix atmospheric nitrogen through root nodule symbiosis with Frankia bacteria, which allows them to grow in very poor, alkaline, or disturbed soils. Both species can be grown in the UK, and silver buffaloberry in particular is available from a small number of specialist UK nurseries. The plant is fully frost-hardy, tolerates exposed, dry positions, and makes an attractive specimen or windbreak shrub in a sunny, well-drained UK garden. It is dioecious (separate male and female plants are needed for fruit); a single male will pollinate up to 5 female plants. In practice, UK growers typically obtain a mixed group. The berries are edible and are considered a delicacy in some parts of North America; their very high saponin content causes them to foam when agitated.

Q: What do buffaloberries taste like?

Buffaloberries (Shepherdia argentea) are extremely tart, acidic, and bitter when eaten raw; the flavour has been described as a cross between redcurrant and unripe tomato, with a strong astringency. The berries contain very high levels of lycopene (which gives them a red-orange colour), vitamin C, and saponins; the saponin content is notable because it causes the berries to foam strongly when agitated with a beater or whisk, which is the basis for the traditional indigenous North American preparation known as 'Indian ice cream' (sxusem in the Okanagan language). This dish is made by whipping buffaloberries vigorously (traditionally with a stick or by hand) with a small amount of water or animal fat until a pink foam forms; the result has a texture similar to meringue or whipped cream and is traditionally sweetened with sugar or dried fruit. The dish is still prepared by indigenous communities across the Great Plains and Plateau regions. Cooked buffaloberries become milder and are used in jams, jellies, sauces, and wine; when sweetened, they develop a pleasant cranberry-like flavour. In UK gardens, the berries of planted shrubs are rarely eaten because UK growers are often unaware of their culinary potential; they are considered an ornamental and edible novelty rather than a productive fruit crop.

Q: How do I grow buffaloberry in the UK?

Buffaloberry (Shepherdia argentea) requires full sun and very well-drained soil with low to moderate fertility; it does poorly in wet, heavy clay soils or in heavily fertilised beds. It tolerates chalk and alkaline soils well, which distinguishes it from most fruiting shrubs. Plant in spring in a sunny, open position; space at 2 to 3 metres. Buffaloberry is dioecious: plant at least one male plant alongside female plants to ensure fruiting. The silver-grey foliage is attractive throughout the season; the plant also provides value as a wildlife plant (the berries are eaten by birds). No regular pruning is required beyond removing dead wood; the thorns make pruning of silver buffaloberry uncomfortable without gloves. Once established, buffaloberry requires minimal irrigation and is among the most drought-tolerant fruiting shrubs that can be grown in the UK. Avoid fertilising with nitrogen; the plant's root nodules provide all the nitrogen it needs. In very fertile UK soils, excessive vegetative growth can be a problem; grow in a lean position. Propagation from seed requires cold stratification (6 weeks at 4°C); layering and root cuttings are also possible.

Buffaloberry (Shepherdia argentea, silver buffaloberry) is a thorny, nitrogen-fixing, drought-tolerant shrub from North American prairies with distinctive silver-grey foliage and small, intensely tart red-orange berries. Unlike most fruiting shrubs, it thrives in poor, dry, even alkaline soils and requires no nitrogen fertiliser because its root nodules fix atmospheric nitrogen. When the silvery leaves curl or distort in UK cultivation, drought stress or aphid infestation are the most likely culprits.

Drought stress

Although buffaloberry is highly drought-tolerant when established, newly planted specimens in the UK can suffer from drought stress because they have not yet developed the deep root system that allows mature plants to find water in dry conditions. In its native prairie habitat, buffaloberry develops roots several metres deep in well-drained soil; in UK cultivation in shallow or compacted soil, this deep rooting may be restricted. Drought-stressed buffaloberry shows wilting and curling of the younger leaves first; the silvery leaf surface (caused by a covering of fine scales) may give a dry, papery appearance.

What to do

Water newly planted buffaloberry through the first two to three growing seasons during dry spells; established plants require little irrigation. Do not overwater or create waterlogged conditions, which is more damaging to buffaloberry than drought. Mulch around the root zone to reduce evaporation. Once established in well-drained soil, buffaloberry rarely needs watering in a typical UK climate.

Aphids

Aphids can colonise the young shoot tips of buffaloberry in spring, causing the tender new leaves to curl and distort. The infestations are usually short-lived as natural predators (ladybirds, lacewings, hoverfly larvae) build up in response; buffaloberry is not as severely affected by aphids as soft fruit species such as gooseberry and blackcurrant. However, on young plants or in early spring when predators are still scarce, heavy aphid colonies on the growing tips can cause noticeable leaf curl and slow the growth of new shoots.

What to do

Check the shoot tips from April. Knock aphids off with a strong water jet or pinch off the most heavily colonised tips. Apply insecticidal soap if the infestation is heavy. Encourage natural predators by growing flowering plants alongside. On established, healthy buffaloberry, aphid damage rarely requires intervention; natural predators typically resolve the problem without help.

Leaf rust

Leaf rust (Puccinia species) can affect buffaloberry, producing small, bright orange or yellow pustules on the undersides of the leaves and corresponding pale, yellow spots on the upper surface; severely infected leaves may curl and drop. Rust on buffaloberry is relatively uncommon in UK gardens but can occur in wet summers. Puccinia rusts typically have alternate hosts (they require two different plant species to complete their life cycle), so identifying and removing alternate host plants in the vicinity can help reduce rust pressure.

What to do

Remove and destroy infected leaves. Improve air circulation by pruning out congested growth. Apply a sulphur-based fungicide at the first sign of infection, repeating every 14 days. Avoid wetting the foliage when watering. On buffaloberry, rust infections rarely cause serious long-term harm to an established, vigorous plant.

Waterlogging

Waterlogging is more damaging to buffaloberry than drought; the plant is adapted to the freely draining, arid conditions of the North American prairies and has no tolerance for waterlogged soil. In UK heavy clay soils or in low-lying positions, waterlogged roots quickly develop root rot. The first sign is yellowing leaves, then wilting and sudden collapse; the distinction from drought-induced wilt is that the soil is wet rather than dry. If waterlogging is the cause, the roots will be brown and mushy rather than white and firm.

What to do

Ensure planting sites are very well drained; break up any hardpan below the planting hole and add grit or gravel if the soil drains poorly. Plant on a slope or raised mound in heavy clay gardens. Do not plant in depressions where water collects. In container cultivation, ensure excellent drainage and do not allow the pot to sit in standing water.

Frequently asked questions

Why are my buffaloberry leaves curling?

Buffaloberry (Shepherdia argentea) leaves curl most commonly because of drought stress in newly planted specimens, aphid infestation on the young shoot tips in spring, or leaf rust. Waterlogging is more damaging than drought and causes root rot and sudden collapse rather than leaf curl. Buffaloberry is very hardy and generally low-maintenance once established in a well-drained, sunny position.

What is buffaloberry and can I grow it in the UK?

Buffaloberry (Shepherdia argentea) is a thorny, nitrogen-fixing shrub from North American prairies with silver-grey leaves and tart red-orange berries. It tolerates chalk, alkaline soils, drought, and poor fertility; it does poorly in wet or heavy soils. It is dioecious (separate male and female plants needed for fruit). Fully frost-hardy; available from specialist UK nurseries. An ornamental and productive curiosity for sunny, well-drained UK gardens.

What do buffaloberries taste like?

Buffaloberries are extremely tart, acidic, and slightly bitter raw; cooked or sweetened, they develop a cranberry-like flavour. Their high saponin content causes them to foam vigorously when beaten, which is the basis for the traditional indigenous North American preparation called "Indian ice cream" (sxusem): the berries are whipped with water until a pink meringue-like foam forms and then sweetened. In UK gardens, the berries are rarely used for cooking despite being edible.

How do I grow buffaloberry in the UK?

Plant in full sun in very well-drained, low-fertility soil; tolerates chalk and alkaline conditions. Dioecious: plant at least one male plant alongside female plants for fruit. No nitrogen fertiliser is needed (root nodules fix atmospheric nitrogen). Minimal pruning required. Very drought-tolerant once established. Space at 2 to 3 metres. Cold-stratified seed or layering for propagation.