Abeliophyllum distichum, the white forsythia or Korean forsythia, is one of the most rewarding and underused shrubs in the UK garden. In February and March it covers every bare stem in fragrant white or pale pink blossom at a time when the garden offers almost nothing else. The variety 'Roseum' produces flowers with a warm pink flush. The scent is sweet and noticeable even from a few feet away, and the display comes without any effort from the gardener: abeliophyllum flowers reliably, tolerates most soils, and reaches a very manageable 1 to 1.5 metres. It belongs to the olive family and is closely related to forsythia, differing most obviously in its white flowers rather than yellow and in a slightly more arching, open habit.
Despite its attractions, abeliophyllum remains rare in UK gardens compared to forsythia. Those who do grow it tend to become devoted to it, pairing it with witch hazel, sarcococca, and other winter-flowering plants for a border that earns its space from November through to April. In cooler gardens and in the Midlands and north, it performs best against a warm south or west-facing wall, which ripens the wood through autumn and encourages a far more generous flower display than an open freestanding position provides.
When the leaves of abeliophyllum start to curl, the cause is usually straightforward. The two most common problems are aphid colonies on the lush new spring growth that follows flowering, and drought stress on plants in a wall's rain shadow. A handful of other issues, including powdery mildew, late frost, and coral spot on dead wood, are worth knowing about as well.
Cause 1: Aphids on spring growth
The weeks immediately after flowering are when abeliophyllum pushes its most vigorous growth of the year. The bare stems that carried the white blossoms through February and March suddenly break into leaf, producing a flush of soft, thin-textured new foliage that is unusually tender and rich in the nutrients that aphids seek. This combination of timing and tissue quality makes the spring growth of abeliophyllum a reliable target for generalist aphid species, most commonly the peach-potato aphid, Myzus persicae.
Aphid colonies on abeliophyllum are typically found on the undersides of the youngest leaves and at the soft growing tips of new shoots. The feeding causes the affected leaves to curl downward and inward, cupping around the colony and partially concealing it. If you unfurl a curled leaf you will usually find a dense cluster of small, soft-bodied, pale green or yellowish insects. The feeding also produces copious honeydew, a sticky sugary secretion that coats the leaf surfaces below the colony and supports the growth of sooty mould, giving the leaves a shiny, slightly tacky look before the black sooty coating develops on top.
On established abeliophyllum plants, aphid colonies in spring are usually self-limiting. Ladybirds, hoverfly larvae, lacewing larvae, and parasitic wasps arrive through late April and May and reduce the colonies rapidly, often collapsing a large infestation within a week or two of natural predators finding it. The foliage may remain slightly distorted where curled leaves have hardened off in the rolled position, but the plant grows through this without lasting harm. On a young or recently planted abeliophyllum where every leaf is valuable for establishment, or on a plant that has suffered other stresses, a heavy early aphid attack can set back growth more noticeably.
What to do
For light to moderate infestations on established plants, the most effective and ecologically sensible approach is to wait for natural predators and do nothing except monitor. A strong jet of water from a hose directed at the undersides of the affected leaves and shoot tips dislodges many aphids physically and creates humidity that slows colony growth, without killing the beneficial insects you want to encourage. For heavier infestations, or where a young plant needs more active protection, apply an insecticidal soap spray directly to the colonies on the leaf undersides and shoot tips, repeating after seven to ten days. Insecticidal soap kills aphids on contact but breaks down quickly and does not persist to harm arriving predators. Avoid systemic insecticides and broad-spectrum sprays, which kill the ladybirds and hoverflies that provide natural control through the rest of the season.
Cause 2: Drought stress
Abeliophyllum produces notably thin, soft foliage that wilts and responds to water stress more visibly than most garden shrubs. The leaves curl inward along the midrib as the plant reduces the surface area exposed to sun and wind, and they lose their fresh mid-green colour, becoming slightly dull and grey-green in prolonged dry conditions. In severe drought the tips of the curled leaves may start to brown.
This sensitivity to drought is particularly relevant for abeliophyllum grown against a wall, which is precisely the position that produces the best flowering. The base of a wall sits in a rain shadow where a significant proportion of UK rainfall never reaches the soil, and the wall itself stores and radiates heat that accelerates moisture loss from both plant and soil. A wall-grown abeliophyllum in a dry summer can be in genuine drought stress even after what feels like adequate rain, because most of that rain never made it to its root zone.
Abeliophyllum is more drought-sensitive than forsythia, which has a more vigorous root system and thicker, slightly more waxy foliage. This is worth bearing in mind when both plants are growing in similar conditions: forsythia will look completely healthy through a dry spell that leaves abeliophyllum visibly stressed.
What to do
Water at the base of the plant rather than overhead, directing water to the root zone rather than the foliage. Wall-grown plants benefit from watering during dry spells throughout the growing season, not just in the first years after planting. A generous mulch of composted bark or well-rotted compost applied each spring, kept clear of the crown and stems, reduces moisture loss from the soil significantly and moderates the extreme temperature swings at root level that worsen drought stress. In a dry period, a thorough deep watering every seven to ten days is more effective than frequent shallow watering, which encourages a shallow root system and increases susceptibility to drought in subsequent seasons. Abeliophyllum recovers quickly from moderate drought stress once watering resumes, with the leaves uncurling within a day or two as soil moisture is restored.
Other causes worth checking
Powdery mildew affects abeliophyllum in warm, dry summer conditions, producing a white floury coating on the leaf surfaces and causing the margins to curl and distort. It is most common on plants in crowded positions where air circulation through the foliage is restricted. Abeliophyllum's open, arching habit means good airflow is usually maintained naturally, but dense planting against a wall or in a tight border can create the stagnant air conditions that mildew fungi favour. Remove and bin affected leaves, prune to improve airflow, avoid wetting the foliage when watering, and apply a potassium bicarbonate spray at the first sign of white coating on the leaves.
Late frost is a specific risk for abeliophyllum because it flowers so early. The flowers open on bare stems in February, sometimes into early March, when hard frosts remain common across much of the UK. A late frost after the flowers are fully open blackens and kills the open blossoms within hours, turning the fragrant white display to brown papery ruin overnight. The emerging foliage in March is similarly vulnerable: the young leaves that follow the flowers emerge when frosts are still possible, and a sharp frost on newly unfurled foliage causes blackening and curl at the leaf tips and margins. A wall position provides some protection from radiation frost, and fleece draped over a wall-trained plant on forecast hard-frost nights can protect the flowers during the critical two or three weeks of peak bloom. Frost-damaged leaves are not worth treating; remove them or leave them to fall naturally and allow the plant to push new undamaged growth.
Coral spot fungus (Nectria cinnabarina) occasionally appears on dead wood in abeliophyllum, producing the characteristic small salmon-pink pustules on the bark of dead or dying stems. Coral spot is a wound pathogen that enters through dead wood rather than a primary cause of leaf problems, but an infected branch can cause the leaves on that section to wilt and curl as the branch dies back. Cut back any dead wood to healthy green tissue and dispose of it well away from the plant; coral spot spreads from the infected wood to healthy tissue nearby if dead material is left in contact with the plant.
Leaf spot diseases caused by various fungal pathogens occasionally produce brown spots with yellow margins on abeliophyllum leaves; heavily spotted leaves may cup or curl as the affected tissue dies. The spots are discrete lesions rather than the diffuse white coating of mildew, and they typically appear from late summer onwards. Removing fallen leaves in autumn reduces the spore reservoir that causes reinfection the following season.
Scale insects can establish on the older wood of abeliophyllum in sheltered wall positions, where the combination of warmth and reduced natural predator activity allows populations to build. Heavy scale infestation produces honeydew and sooty mould on stems and leaves, and can weaken the plant over time. Brown soft scale (Coccus hesperidum) is the species most likely to be encountered. Treat in late spring when the juvenile crawler stage is active with a fatty acid or neem oil spray applied to all stem surfaces.
Prevention
Prune abeliophyllum immediately after flowering ends in late February or March, before the leaves emerge. This is the single most important cultural practice for maintaining a healthy, well-shaped plant. Removing a proportion of the oldest stems at the base each year encourages strong new growth from the crown through summer; it is this vigorous new growth that carries next year's flower buds, so the quality of the pruning directly affects next winter's display. Mulch generously each spring to retain soil moisture through summer, and water during dry spells, particularly for wall-grown plants in a rain shadow. Monitor the emerging spring foliage for the first signs of aphid colonies on the new growth and decide at that point whether the infestation warrants action or whether natural predators can be trusted to deal with it. Avoid overhead irrigation at all times, both to limit the humid conditions that favour mildew and to avoid wetting the flower buds in late winter when they are about to open.
Abeliophyllum distichum is an exceptional plant for UK gardens that deserves to be far more widely grown. It pairs beautifully with witch hazel, sarcococca, Daphne bholua, and other winter-flowering shrubs to create a border with genuine four-month interest from November through to March. It grows well in sun to partial shade, tolerates most well-drained soils, and requires only light annual pruning to remain in good shape. The fragrant white flowers on bare stems in the depths of winter are one of the garden's most unexpected and genuinely uplifting sights.
Frequently asked questions
Why are my abeliophyllum leaves curling?
The two most common causes are aphid colonies on the soft new spring growth and drought stress, particularly on plants grown against a wall in a rain shadow. Aphids cause the young leaves to curl downward with honeydew deposits visible on the surfaces below the colonies. Drought causes the thin foliage to curl inward, losing its fresh colour. Powdery mildew in warm dry summers and late frost damage on the emerging foliage in February and March are also worth checking.
Is abeliophyllum the same as forsythia?
Abeliophyllum distichum is closely related to forsythia and belongs to the same plant family, Oleaceae, but it is a distinct genus with one species. The key difference in flower colour is striking: forsythia produces bright yellow flowers while abeliophyllum produces white or pale pink flowers. Abeliophyllum flowers slightly earlier than forsythia in most UK gardens, typically in February and March, on bare stems before the leaves appear. It is rarer in UK gardens than forsythia but equally easy to grow and arguably more elegant, with its fragrant white blossoms having a subtlety that yellow forsythia lacks.
Why is my abeliophyllum not flowering?
Poor flowering on abeliophyllum is most often caused by pruning at the wrong time, by insufficient sun to ripen the wood in autumn, or by late frosts damaging the flower buds before they open. Prune immediately after flowering ends in March, before the leaves emerge, as the new growth produced after that pruning will carry next year's flowers. Pruning in autumn or late summer removes the flowering wood and results in a bare spring the following year. In cooler or shadier positions, planting against a warm south or west-facing wall dramatically improves flowering by ripening the wood through autumn.
How do you prune abeliophyllum?
Prune abeliophyllum immediately after flowering in late February or March, before the leaves open. Remove about a quarter to a third of the oldest stems at the base to encourage vigorous new growth from the crown; this new growth will carry the following year's flowers. Lightly shorten any very long or untidy stems to maintain the shape. Wall-trained plants can have the sideshoots shortened back to two or three buds from the main framework after flowering. Avoid pruning in late summer or autumn, which removes the ripened wood that carries the flower buds.
Does abeliophyllum grow well against a wall in the UK?
Yes. A warm south or west-facing wall is the ideal position for abeliophyllum in UK gardens, particularly in the Midlands and northern England where summer warmth is less reliable. The wall radiates stored heat that ripens the wood through autumn and encourages better flower bud development; this translates directly into a more generous flowering display in February and March. The wall also gives some protection from the worst winter winds, which can desiccate the flower buds. Even in milder southern gardens a wall position produces noticeably better flowering than an open freestanding position.