When to Plant Hyacinth Bulbs (and How to Force Them for Christmas)

Few spring flowers earn their place like hyacinths: dense spikes in blue, pink, white and apricot, with a perfume strong enough to fill a room from a single pot. And they are one of the easiest bulbs of all — if you get the timing right. September is the month that matters, both for planting outdoors and for starting the pots that will flower on the Christmas table.

When to plant hyacinths outdoors

Early to mid-autumn — September and October — is ideal. The soil is still warm enough for bulbs to root well before winter, which is exactly what a hyacinth needs to throw a full flower spike in March or April. You can plant as late as November and still get flowers, though they may arrive a little later and shorter in the first spring. (Unlike tulips, which actually prefer a November planting, hyacinths gain nothing from waiting.)

How to plant them

• Choose the fattest, firmest bulbs you can find — spike size is decided by bulb size — and reject anything soft or mouldy.
• Pick a sunny or lightly shaded spot with well-drained soil; bulbs rot in winter-wet ground. In heavy clay, add coarse grit to the planting hole or use containers.
• Plant 10 cm deep and 7–8 cm apart, pointed end up.
• Plant in groups of at least five — hyacinths look municipal in rows, glorious in clumps.
• Water once after planting, then leave winter to do the rest.

Warning: handle hyacinth bulbs with gloves. They contain oxalate crystals that give many people an itchy rash known as "hyacinth itch". They are also toxic to cats and dogs — the concentrated toxins are in the bulb itself, so keep sacks of bulbs out of reach and cover freshly planted areas if your dog is a digger.

Forcing hyacinths for Christmas

A bowl of scented hyacinths in flower midwinter is one of gardening's best tricks, and September is when it starts. You need "prepared" bulbs — ones the supplier has pre-chilled to fool them into thinking winter has already happened. Ordinary bulbs forced indoors will flower too, but not until late winter.

• Early to mid-September: pot prepared bulbs in bulb fibre or ordinary peat-free compost, shoulders touching, noses just proud of the surface.
• Water lightly, then give them 10–12 weeks somewhere dark and cold (under 9°C) — a shed, garage, cellar or a spare fridge shelf all work.
• Check monthly and keep the compost barely moist.
• When shoots reach about 5 cm and the flower bud is clear of the bulb's neck, bring the bowl into a cool, bright room (not straight to a warm one, or the leaves stretch and flop).
• After a week or two of acclimatising, move it to the warm room where you want the display; flowers open about three weeks after the pots come indoors.

Tip: pot two or three bowls a fortnight apart, and store some in a cooler spot than others. Staggered starts give you a relay of flowers from Christmas to February instead of one crowded, glorious week.

No garden shed required: hyacinths also force beautifully in water. Sit a bulb in a hyacinth vase (or any glass that holds it above the water) with the water level just below the base of the bulb, and give it the same cold, dark rooting period before bringing it into the light. Watching the roots fill the glass is half the pleasure.

After flowering

When the flowers fade, cut the spike off at its base but leave every leaf — the foliage feeds next year's bulb for about six weeks before it yellows and can be cleared. Feed plants in the ground or in containers with a high-potassium fertiliser while the leaves are green. Forced bulbs cannot be forced a second time, but they are not spent: plant them out in the garden once frosts ease and they will flower outdoors in future springs. Garden hyacinths return for years, with spikes that become looser and more informal — many gardeners prefer them that way; if you want fat show spikes, add a few fresh bulbs each autumn.

If something goes wrong

• Leaves but no flower ("blind" bulbs) — usually a too-short or too-warm cold period when forcing, or an undersized bulb outdoors.
• Floppy, stretched leaves and stems — brought into warmth too fast or kept too dark; stake discreetly this year, acclimatise more slowly next.
• Bulbs rotted in the ground — waterlogged soil. Replant on grit or switch to pots.
• Spikes shrinking year on year — normal; feed after flowering and replace a few bulbs annually.

And if you cannot tell whether that green nose pushing up in February is the hyacinth you planted or something else entirely, point PlantMe at it — the app identifies plants from a photo at any stage, bulbs included.