Why Are My Narcissus Leaves Curling?

Narcissus fly

The large narcissus fly (Merodon equestris) is the most damaging pest of narcissus in UK gardens. The bumblebee-mimic adult fly lays eggs at the base of the leaves in late spring after the flowers have faded. The resulting larva tunnels down into the bulb and feeds on the interior through summer, hollowing it out completely. In the following spring, the damaged bulb produces a characteristic cluster of few, narrow, grass-like leaves that curl and twist but no flower spike. When you dig up the bulb, you find it partially or completely hollowed out, often with the larva still inside. The small narcissus fly (Sminthurus viridis) causes similar but less severe damage, and multiple larvae attack smaller bulbs.

What to do

• Cover the bulb area with fine insect mesh or horticultural fleece immediately after flowering until the leaves have fully died back, typically from April to June. This is the most effective prevention available to gardeners.
• Firm the soil over the bulb area as the leaves begin to die down: this reduces the fly's ability to find the bulb neck and lay eggs.
• Lift and inspect bulbs every three to five years when dividing: discard any that are soft, light, or contain larvae.
• Lifting and storing bulbs dry through summer removes them entirely from fly risk: replant in autumn.

Basal rot

Basal rot, caused by the soil-borne fungus Fusarium oxysporum f.sp. narcissi, is one of the most serious diseases of narcissus in the UK. The fungus attacks the basal plate of the bulb, causing it to turn brown and deteriorate. The roots rot and the plant is unable to take up water and nutrients properly. Affected leaves turn yellow, curl, and the plant fails to flower. When you dig up a bulb with basal rot, the base has a characteristic brown, dry rot with a reddish-brown discolouration that progresses up through the bulb. Basal rot spreads through the soil and through infected bulbs and can persist for many years.

What to do

• Dig up and destroy all affected bulbs immediately. Do not compost basal rot-infected material as the fungus can persist in compost.
• Avoid replanting narcissus in an area known to have basal rot for several years.
• Purchase only firm, sound, dry bulbs from reputable sources. Inspect carefully before planting: discard any that show brown discolouration at the base.
• Ensure good soil drainage: wet conditions favour the spread of Fusarium basal rot. Well-drained soil significantly reduces the risk.
• Dip bulbs in a fungicide solution before planting in areas where basal rot has been a previous problem.

Narcissus eelworm

Narcissus stem and bulb eelworm (Ditylenchus dipsaci) is a microscopic nematode that lives inside the bulb and stem tissue of narcissus. Infested plants produce distorted, curling, twisted leaves with characteristic yellow rings or bumps on the stem (called spikkels). The plants are usually stunted and do not flower normally. When you cut through an infested bulb, you see characteristic brown ring markings in the white flesh. Eelworm spreads through infected bulbs, tools, and soil. There is no chemical treatment available to gardeners.

What to do

• Dig up and destroy all plants showing characteristic leaf distortion, curling, and the yellow-ring stem markings. Do not compost eelworm-infested material.
• Do not replant narcissus in an infested area for at least six years. The eelworm can survive without a host in the soil for several years.
• Disinfect tools with a garden disinfectant between working in different areas. Do not move soil from infested areas.
• Purchase only certified disease-free bulbs from reputable suppliers.

Waterlogging

Waterlogging causes narcissus bulbs to rot, producing leaves that curl and yellow in spring as the deteriorating bulb struggles to supply the expanding growth. Narcissus is substantially more tolerant of wet conditions than many bulbs and naturalises successfully in damp meadows, but persistently waterlogged, anaerobic soil in winter and spring causes basal rot and root deterioration. Container-grown narcissus without adequate drainage is particularly at risk.

What to do

• In very poorly drained soil, improve drainage with coarse grit or plant in raised beds. Narcissus tolerates moist soil but not standing water for extended periods.
• In containers, ensure excellent drainage holes and use a free-draining bulb compost. Never leave containers sitting in saucers of water through winter.
• In lawns where narcissus is naturalised, ensure the grass is not compacted or waterlogged: aerate the lawn in autumn to improve drainage around the bulbs.

Overcrowding

Overcrowding is the most common reason established narcissus clumps begin producing blind stems (leaves with no flowers) and increasingly curled or distorted foliage. As narcissus bulbs increase by producing offsets, the competition for water, nutrients, and space in densely packed clumps causes individual bulbs to be unable to accumulate the resources needed to build a flower bud. The leaves become progressively smaller and more crowded. This typically becomes a problem after five to eight years in established plantings.

What to do

• Lift and divide overcrowded clumps in early summer, immediately after the leaves have fully died back. Separate the individual bulbs and replant at the correct spacing of 10 to 15 cm apart.
• Feed established clumps with a high-potash fertiliser immediately after flowering each year. This supports the development of next year's flower bud in the bulb.
• Allow the leaves to die back completely (at least six weeks after flowering) before removing them. Early removal of the leaves significantly reduces the bulb's ability to store energy for the following season.

Frequently asked questions

Why are my daffodil leaves curling?

Daffodil leaves curl most often from narcissus fly damage or basal rot. The large narcissus fly lays eggs at the base of the leaves in late spring and the resulting larva hollows out the bulb over summer. In spring, the damaged bulb produces few, narrow, twisted, curling leaves but no flowers. Basal rot (Fusarium oxysporum) causes brown discolouration of the bulb base, preventing water uptake, and the leaves yellow and curl as a result.

Why are my daffodil leaves coming up blind?

Daffodils that produce leaves but no flowers (going blind) are most often the result of overcrowded bulbs that need dividing, narcissus fly damage, insufficient chilling, planting too shallowly, or the leaves being removed too early the previous year before they had fully died back. Feeding with a high-potash fertiliser after flowering and allowing the leaves to die back naturally for at least six weeks after the flowers fade helps restore flowering the following year.

When should I plant narcissus bulbs?

Plant narcissus bulbs in autumn from September to November, at a depth of three times the height of the bulb (typically 10 to 15 cm) in well-drained soil. They perform best in full sun or light dappled shade. Narcissus naturalises readily in grass and increases well by producing offsets over successive years. Established clumps should be lifted and divided every three to five years when flowering begins to decline.

How do I stop narcissus fly?

The most effective prevention against narcissus fly is to cover the bulb area with fine insect mesh or horticultural fleece from the time the flowers finish until the leaves have fully died down, typically from April to June. This prevents the adult flies from laying eggs at the base of the leaves. Firm the soil around the dying leaves as they collapse: this makes it harder for the fly to access the bulb neck. Lifting and storing bulbs dry over summer also removes them from fly risk.