When to plant tulip bulbs

When to plant tulips: three RHS dates

Tulip bulbs go in the ground in autumn, while they are dormant. But the RHS does not give one single date, and its guides differ.

The RHS tulip growing guide says to plant in autumn, from September to November.

The RHS bulb planting guide is more specific. It says to plant daffodils, crocus and hyacinths preferably by the end of September, but to plant tulips in November.

An RHS guide to planting tulips for seasonal colour goes further. It says tulips grow well when planted between September and December, and that if you thought it was too late to plant bulbs, you should think again.

So if you are reading this in November, you are right on time. Even into December, one RHS guide says you can still plant.

Plant soon after you buy

The date matters less than how long the bulbs sit in the bag. The RHS seasonal guide says the key is to plant as soon as you can after buying or receiving them by mail order, so they do not deteriorate before they go in the ground.

The RHS bulb planting guide explains why. Bulbs are bought dry and dormant, without leaves or roots. They may flower poorly if planted later than recommended or after lengthy storage. It adds that some bulbs store longer than others, comparing tulips with daffodils, so late planting is a bit hit and miss.

The RHS tulip guide also notes that tulips with short stems may be the result of late planting, or mild winters.

Depth, spacing and soil

The RHS tulip guide says to plant bulbs at a depth of two to three times their height and to space them at least twice their width apart, with the pointed end uppermost. The bulb planting guide gives an example: for a bulb 5 cm high, dig a hole 10–15 cm deep. It also suggests planting in groups of at least six, because more bulbs together make a better display.

In areas with very cold winters, the tulip guide says tulips benefit from deeper planting to protect them from frost getting into the ground. It also says that tulips which do not flower are caused by shallow planting, and to replant such bulbs at least three times their depth in the ground.

Tulips grow best in full sun, though some tolerate light shade. They prefer nutrient-rich, free-draining soil that is neutral to alkaline, the RHS says, but will flower fine as long as the ground is not waterlogged.

Tulip fire: check your bulbs first

Tulip fire is caused by the fungus *Botrytis tulipae*, the RHS says. Leaves come up distorted or twisted, with brown patches of dead tissue. In damp weather a fuzzy grey mould appears.

The fungus forms small black seed-like bodies called sclerotia. They can contaminate the soil for several years and also stay in the outer scales of the bulb. So before planting, check your bulbs carefully and throw away any with sclerotia in the outer scales or any sign of decay.

If tulip fire has appeared in a bed, the RHS says do not plant tulips there for at least three years. Space bulbs adequately and plant them where the air circulates well. There are no chemical controls available to home gardeners for tulip fire.

Squirrels

The RHS tulip guide says grey squirrels often dig up bulbs. Its bulb planting guide names tulips and crocus as the bulbs squirrels go for most.

One idea from the RHS: interplanting tulips with daffodils, which squirrels avoid, may reduce your losses.

Slugs can also damage the leaves and flowers in early spring, the RHS adds. Our slugs guide covers what UK sources say about them.

Tulips in pots

For containers, the RHS tulip guide mixes three parts peat-free multipurpose compost with one part grit. For a fuller display, it suggests a bulb lasagne: two or three layers of bulbs in one pot.

The bulb planting guide has two mixes. For long-term displays, use three parts peat-free John Innes No 2 to one part grit. For a single season, use three parts peat-free multipurpose compost to one part grit. In pots it plants bulbs at three times their depth and one bulb width apart, and keeps the compost moist but not waterlogged.

The RHS seasonal guide adds that smaller tulips work well in containers, small gardens and gravel, and are less likely than taller ones to be damaged by spring gales.

Watering and feeding in spring

Tulips in beds and borders usually do not need watering if there is enough rain to keep the ground damp, the RHS says. Only water in prolonged dry spells of more than two to three weeks, aiming for moist, not soggy, ground. A shortage of water can cause poor development or a shorter flowering period.

Once the plants are growing, from March onwards, the RHS feeds them weekly with a potassium-rich liquid fertiliser such as tomato feed, and stops once the leaves begin to yellow and die back. If you grow tulips as bedding and throw the bulbs away after flowering, there is no need to feed them.

Which tulips come back every year

The RHS tulip guide says border tulips often fail to flower in their second year when left in the ground. A few, such as the Darwin hybrids and Kaufmanniana cultivars, are known to flower again with greater certainty, and some other cultivars can be left in the ground where they often flower for several years.

Specialist tulips, such as alpine species, can be left undisturbed in pots or in the ground, where they often multiply naturally. The RHS seasonal guide also mentions varieties suitable for permanent planting, or even naturalising in wilder parts of the garden.

Lifting and storing bulbs

After flowering, the RHS deadheads by cutting off the stalk just above the leaves. If you leave the bulbs in, remove the withered stems and leaves in summer once they have turned straw-coloured.

To lift them, wait until the leaves turn yellow, about six weeks after flowering. Let the bulbs dry thoroughly, until the brown skin becomes papery. Store them in trays or net or paper bags in a warm, dark, well-ventilated place at 18–20 °C, then replant in autumn, from September to November.