Tulips are tougher than they look, but a wet British spring can undo a lot of autumn's good work. A row that seemed immaculate in April can be full of ragged leaves, twisted shoots and streaky petals by early May — and the cause is usually something you can see, catch and deal with in an afternoon. The trick is knowing what you are looking at. Slug damage looks nothing like tulip fire, and mistaking one for the other costs you bulbs and time. Here is what to check for, what to leave alone, and how to keep a tulip bed productive year after year.
Slugs and snails: the night-time raid
The damage is easy to recognise once you know it: ragged, irregular holes in leaves, silver slime trails across the foliage, and young shoots nibbled flat to the ground. Fresh, soft growth in a damp, mild spring is the danger zone, and heavy mulched soil gives slugs somewhere cool to hide during the day.
Go out with a torch after rain and pick them off by hand — it is grim work but remarkably effective, and two or three patrols in a wet week will make a visible difference. Beer traps work if you sink a jar so the rim sits a couple of centimetres above the soil, which keeps ground beetles out. Barriers of copper tape, wool pellets or sharp grit help on pots and dry soil, though they lose their edge in constant rain. Biological slug nematodes, watered onto moist soil when the ground has warmed, are worth using in late spring and again in early autumn.
If you use pellets, check the current UK rules first: metaldehyde products are no longer approved for outdoor garden use, and ferric phosphate is the usual alternative. Use any pellet sparingly, and keep children and pets away from treated beds. Encouraging thrushes, frogs, hedgehogs and ground beetles does more for you long term, so leave a rough corner somewhere in the garden.
Aphids, and the viruses they carry
From April, check buds, stems and the undersides of leaves. Aphids cluster there, leaving sticky honeydew that turns into a sooty black film. A modest colony does little harm on its own — squash them with your fingers or knock them off with a jet of water, and let ladybirds, hoverflies and lacewings do the rest. Avoid high-nitrogen feeds in spring, which push soft growth that aphids love.
The real concern is what they pass on. Tulip breaking virus shows as mottled, streaky leaves and petals flamed with a contrasting colour. There is no cure, and the bulb stays infected, so lift the whole plant and put it in the bin rather than the compost heap. Never save bulbs from a plant with streaked or mottled foliage, however handsome it looks.
Tulip fire: the one to take seriously
Tulip fire, caused by Botrytis tulipae, is the most destructive problem UK growers face. Watch for shoots that emerge twisted, stunted or bent over, then develop pale brown spots with soaked-looking edges. In damp weather the spots grow a grey, fuzzy mould, and a badly affected leaf looks scorched, as though someone held a flame to it. Bulbs in the ground can rot away entirely.
The fungus survives in the soil and on bulb skins for years, so the same patch can reinfect new plantings. Act the day you spot it: lift the entire plant with its bulb and a generous trowel of surrounding soil, bag it and bin it. Never compost it and never drop it back on the bed. There is no garden fungicide that cures tulip fire, so prevention carries the weight:
- Plant late — late October into November — when cooler, drier soil slows the fungus.
- Space bulbs 15–20cm apart in full sun, in soil that drains freely; add grit to heavy clay.
- Water the soil, not the foliage, and avoid crowding tulips among wet-loving perennials.
- Deadhead as petals fall, and let the leaves die back naturally.
- If you lift bulbs to store, dry them thoroughly and keep them cool and airy.
- Avoid growing tulips on the same ground for several years after an outbreak.
Bulb rots and eelworm
Basal rot usually announces itself as a plant that yellowss and stalls while its neighbours romp away. Lift it and the bulb base will feel soft and smell faintly unpleasant, with brown, dusty patches and poor roots. It often follows damage — a nicked bulb, a waterlogged winter, a heavy soil. Bin the affected bulb and the soil clinging to it, and improve drainage before replanting.
Eelworm is less common but nastier. Shoots come up swollen, stunted and misshapen, sometimes split or blind, and the bulb inside is soft and rotten. This is the classic "tulip root" picture, and there is no treatment. Lift and bin the plants, and do not grow tulips on that ground for several years.
Bulbs in store can also rot. Check them monthly, keep them in a cool, dark, airy place in shallow boxes or net bags — never sealed plastic — and throw out anything with brown, dusty patches or a soft feel.
Furry and feathered visitors
Squirrels dig bulbs up and carry them off; mice and voles eat them underground, leaving tidy holes and no bulbs. Deer and rabbits graze the leaves and bite the buds off cleanly just as they colour. Planting deeper than feels necessary, at roughly three times the bulb's height, helps. So does laying chicken wire flat over the bed after planting and pegging it down, removing it as shoots emerge. For deer and rabbits, netting or fleece over the buds is usually the only reliable answer. Fresh manure and blood-based fertilisers attract digging animals, so keep those for spring.
Quick diagnosis
- Ragged holes, slime trails, shoots cut off overnight: slugs and snails.
- Mottled leaves, petals flamed with another colour: virus. Lift, bin, do not save the bulb.
- Twisted shoots, brown spots, grey mould: tulip fire. Remove with the surrounding soil at once.
- Swollen, stunted, misshapen stems and a soft bulb: eelworm. Clear the ground and rotate.
- Holes where bulbs used to be: squirrels, mice or voles.
- Sticky residue and clusters on buds: aphids. Squash and encourage predators.
- Leaves yellowing from the base after flowering: usually natural dieback. Leave them for six weeks.
A simple routine that prevents most trouble
Buy firm, clean bulbs from a supplier you trust, and give them a quick squeeze before planting — anything soft or mouldy goes back. Choose the sunniest, best-drained spot you have, and if your soil is heavy clay, plant in pots or add grit and compost to the planting hole. Plant late. Keep a note of which beds have had tulip fire or eelworm, and treat those patches as tulip-free for several years.
Then walk the bed once a week from March, secateurs and a bag in hand. Most problems are far easier to deal with on day one than on day ten, and a single infected tulip left in place can spoil a whole row. Bin rather than compost, water the roots rather than the leaves, deadhead faithfully, and let the foliage ripen until it yellows. Treat tulips as short-term tenants rather than permanent residents, and they will reward you with a spring display worth the small effort.
Photo: Marjonhorn / Pixabay
