When to plant hostas: spring, summer or autumn?

Hostas are forgiving about planting time, but not endlessly so. The RHS says they can go in at almost any time of year apart from the height of summer, yet a bare-root division, the way our hostas travel, has needs of its own. Here is when to plant, month by month, and how to deal with late frosts and hot spells.

When should you plant hostas?

In spring, from the moment the soil can be dug, neither frozen nor sodden, until early summer. The RHS and BBC Gardeners' World both name spring and autumn as the best seasons, and both warn against the height of summer, when heat and dry ground make it hard for new roots to grow. Gardeners' World also rules out midwinter, when the soil is cold and often frozen.

Which of the two good seasons suits you depends on what you are planting. Bare-root divisions belong to spring. A potted hosta that already has leaves and a ball of roots can go in during either season, and the RHS allows container-grown perennials to be planted at any time, as long as the ground is not frozen or waterlogged.

Why we send bare-root hostas in spring

A bare-root division travels without soil, as a crown with buds and roots. It establishes best when it goes into the ground in spring, once the soil can be worked, and keeps growing through early summer. Later in the year two things work against it: there is less time to root before winter, and hot weather is hard on bare roots in transit. That is why we send hostas only between 1 March and 1 July.

Ordering is open all year. Order after 1 July and your plants are put aside for you, then sent from 1 March in the order the orders came in, so they arrive at the start of the season. Our guide to bare-root hostas explains what arrives and how to plant it.

Every variety is sent and planted the same way, fragrant ones such as Fragrant Bouquet and Invincible included. Do not count on flowers in the first summer, though: the RHS says divisions flower from their second year. More scented varieties are among our fragrant hostas.

Planting hostas month by month

The table is a guide, not a timetable: your own soil decides. The test works anywhere. If you can dig a hole without the soil clinging to the spade in clods or crunching with frost, you can plant.

When is the last frost in spring?

Later than many gardeners hope, and the answer depends on where you live and even on where in your garden. The weather services of three countries in north-west Europe give these figures:

Frost is retreating, but slowly. KNMI notes that the last night frost now tends to come about 10 days earlier than it used to, yet on 14 May 2020 De Bilt still recorded −1.0 °C. Two local factors matter as much as the date. In May, the Met Office points out, ground frost is more common than air frost, especially after clear, still nights, and the DWD warns that late frosts strike above all in sheltered hollows, where cold air collects. A low corner of the garden can be white while the rest stays clear.

What if frost comes after planting?

A newly planted division is tougher than it looks. Until the shoots appear, its buds sit at or just below the surface, out of the worst of the cold. The risk starts once the young shoots unfurl, and even then a light frost often does little harm: Iowa State University sees most damage to young hosta leaves below about −2 to −3 °C.

The Hosta Helper, a guide sponsored by the American Hosta Society, describes what a harder frost does. It kills cells inside the tightly rolled shoots, so the leaves open torn and full of holes, and those leaves never heal. Varieties that wake up early are the most exposed. The plant recovers all the same: Iowa State says that when spring frost destroys the young leaves of perennials, the crowns and roots survive and a second flush of leaves follows within a few weeks.

If frost is forecast once the shoots are up, cover them for the night. The RHS suggests two or three layers of fleece; for a single plant, an upturned plastic pot, as the Hosta Helper suggests, does the job too. Take the cover off in the morning. Never dig up a frosted plant: water it once a week if the weather is dry, as Iowa State advises, and let the new leaves come. What else to expect over the next months is in our guide to your hosta's first year.

Can I plant hostas in summer?

In early summer, yes; in midsummer, only if you must. A division planted in June still has the rest of the season to root, but it needs steady moisture. The RHS advises watering well after planting, even when the soil is damp and rain is forecast, and keeping anything planted in summer moist. Iowa State suggests checking new perennials once or twice a week in their first season, and the Met Office reminds gardeners that whatever went in during the last two years needs water in clear, warm and windy weather.

Water deeply whenever the top few centimetres are dry, and spread a mulch over the soil to keep it cool and damp. In a heatwave, shade newly planted hostas for the hottest hours with a sheet of fleece or a garden chair.

Varieties that take more sun, such as the medium to large Summer Breeze, need the same care in their first summer: our product pages rate them for partial shade to sun only as long as the soil stays moist. Our sun-tolerant hostas are no exception while they settle in.

Can I plant hostas in autumn?

Yes, if they are in pots. The RHS gives late September and October as the autumn window for perennials, while the soil is still moist, and potted hostas from a garden centre fit into it well. Water them in dry spells until the weather turns cold.

Autumn is also one of the two times the RHS gives for dividing hostas. The other is early spring, which we recommend for most of northern and central Europe, and the RHS itself says to wait for spring when the autumn is wet. Our guide to dividing hostas compares the advice and shows how it is done.

Bare-root divisions are a spring product. If you are planning a new border in autumn, prepare the soil now and order for the spring season; our full range of hostas can be ordered all year. The planting and care guide covers soil preparation and spacing.

Pots buy you time

A pot gives you more freedom with timing. You can pot up a bare-root division the day it arrives, even if the border is not ready, and plant it out later in the season; the RHS suggests exactly that for bare-root perennials, setting them out a few months on. A potted hosta in leaf can go into the garden in autumn as well. A medium variety such as Praying Hands, which our product page lists as good for large pots, is a sound choice. Our guide to hostas in pots covers pot sizes, compost and winter care.

Common mistakes

• Planting into frozen or waterlogged soil just because the plants have arrived.
• Leaving a box of bare-root divisions unopened for days, waiting for a better weekend.
• Forgetting to water a plant set out in June during its first dry spell.
• Digging up a new plant because nothing has shown after a cold spring week.
• Planting in midsummer heat without shade or regular watering.

In short

• Plant bare-root hostas in spring, as soon as the soil can be dug.
• Watch the frost forecast once the shoots are up, and cover them on cold nights.
• Water new plants whenever the top few centimetres dry out, all through their first summer.
• Leave autumn for potted hostas and for dividing clumps in your own garden.
• Order in winter if you like: we ship from 1 March.