Gadenin日本語Get the appRot is what actually kills established clumps
Almost every nerine that dies outright dies of rot at the base plate, and almost every case traces back to water sitting around the bulb during the summer rest or in a cold wet winter. The bulb goes soft at the bottom, the neck loosens so it lifts out at a touch, and the tissue inside turns brown and smells sour. By the time this is visible the bulb is beyond saving.
The defenses are all structural rather than chemical: sharp drainage, shallow planting with the necks in the air, no organic mulch over the top, and no irrigation in summer. On heavy clay, raise the strip a few inches (7 to 10 cm) and rebuild it with grit, or grow the bulbs in pots where you control the water entirely.
Check for it in autumn as the stems come up. Gently lift one suspect bulb and feel the base. Firm bulbs go back exactly as they were; soft ones come out along with the soil immediately around them, so the rot does not spread through a congested clump.
Pests worth knowing about
Nerine is troubled by few pests, but the ones that do turn up cause damage that is easy to misread as failure to flower. Slugs and snails are the main nuisance outdoors, since a newly emerging stem is soft and sits at ground level for several days. Under glass or in a conservatory, mealybug tucked into the neck of the bulb and between the leaf bases is the common problem, and it is easy to miss because the bulb necks look scruffy anyway.
The bulb fly, whose grubs hollow out the inside of the bulb, occasionally attacks nerine. The symptom is a bulb that produces a few thin leaves and no flowers, then proves hollow and mushy when lifted. There is no cure once grubs are inside; lift and destroy the bulb rather than replanting it.
| Symptom | Likely cause | Response |
|---|---|---|
| Flower stem sheared off near ground level, slime trails nearby | Slugs or snails on emerging buds | Check the strip nightly as stems appear after rain; clear hiding places and use barriers or traps |
| Bulb soft at the base, lifts out easily, sour smell | Basal rot from wet soil | Remove the bulb and surrounding soil, improve drainage, keep the strip dry in summer |
| White fluffy patches in the bulb neck and leaf bases | Mealybug, usually under cover | Wipe out with a cotton bud dipped in alcohol, repeat weekly, improve ventilation |
| Thin sparse leaves, no flowers, bulb hollow when lifted | Bulb fly grubs feeding inside | Destroy the affected bulb; do not replant it or compost it |
| Yellow streaks or mottling running along the leaves | Virus, spread by aphids or on tools | Remove and destroy the affected bulb, control aphids, do not divide from that clump |
| Gray furry mold on flowers in wet weather | Botrytis on damp, crowded blooms | Cut off affected heads, improve air movement, avoid overhead watering |
| Brown scorched leaf tips after frost | Cold damage to winter foliage | No action; the fan recovers. Use a loose grit or dry leaf cover in hard winters |
The failure that is not a failure
Most reports of a sick nerine are not disease at all. A clump with strong leaves and no flowers is almost always planted too deep, shaded in summer, watered in summer, or recently divided, and the plant is perfectly healthy. Reach for the trowel only after you have ruled out all four, since digging to investigate is itself one of the causes.
Equally, a clump that vanishes completely in summer is not dead, and one that shows leaves in the first winter after planting but no flowers is on schedule. The rhythm of this plant, flowering on bare stems and growing through winter, produces a run of apparent emergencies that are simply the plant doing what it does.
The bulbs contain alkaloids and are poisonous if eaten. Handle them with the same care you would give daffodil bulbs, keep them away from children and pets, and wash your hands afterwards, especially if you have been cutting or cleaning rotten bulbs.
What to record when something goes wrong
When you find a problem, write down what you saw, exactly where in the clump it was, and the date. Position matters more than it sounds: rot almost always starts at the wettest end of a strip, and slug damage clusters where there is cover nearby. Two seasons of notes will point at a downpipe, a shaded corner or an irrigation head far more reliably than any single inspection.
Also record what you removed. If you lift rotten bulbs, note how many and from where, so that next autumn you can check whether the gap has stayed a gap or whether the trouble is spreading along the row. That is the difference between a one-off loss and a drainage fault you need to fix before it takes the whole planting.