Hosta: where to plant it by leaf colour and how to protect it from slugs

In brief: Hosta (plantain lily) is a frost-hardy foliage perennial for partial shade and shade. It needs moist, fertile soil and protection from slugs, which are its main enemy. Blue-leaved varieties want shade, yellow-leaved ones tolerate morning sun. It is poisonous to dogs, cats and horses.

Hosta is a plant you buy for its leaves. You will find them in blue-green, yellow, deep green and with white and cream margins, from tiny spoons to leaves as big as a plate. In spring it comes up late, in summer it forms a dense clump that keeps weeds out, and in July to August it adds clusters of white or violet bells.

Two things, however, decide success more than the variety: moist soil and slugs. In this article we deal with both, and also with choosing a spot by leaf colour, dividing clumps and what to watch out for when you have a dog or cat.

Leaf colour tells you where to plant a hosta

It is said that hosta is a plant for shade. It is more accurate to say that it needs shade from the midday sun and that each group of varieties tolerates light differently.

In deep shade under spruces or by a north wall hosta grows, but the clumps are smaller and sparser. In dry places under trees, where roots suck up the water, it does not thrive at all. You can find other plants for shady corners in the articles which plants suit the shade and ornamental perennials.

Planting in a bed and in a container

Hosta is undemanding as to soil type and copes even with heavy clay if you improve it with compost. It dislikes only drought and standing water. You can plant any time from spring to autumn, best in spring or at the beginning of autumn. In midsummer new plants suffer in the heat.

• Dig a hole twice as wide as the root ball and mix the excavated soil with compost.
• Plant it to the same depth as it grew in the container.
• Choose spacing according to final size: miniatures 30 cm, medium 45–60 cm, large-leaved up to 90 cm.
• Water and mulch with compost, which keeps moisture in.

In a container hosta does well and often better, because slugs find it harder to get at. Choose a container 30–45 cm in diameter with drainage holes and a loamy substrate. In summer water regularly and from spring to August add a liquid fertiliser once a month. In winter the container may stay outdoors; just move it against a wall and wrap the root area so that it does not freeze through. Container types are compared in the article what to grow in.

Slugs: a defence plan in six steps

Holey hosta leaves are the most common complaint of growers. Slugs and snails attack mainly in spring the emerging, rolled-up shoots. Every hole in a young leaf grows as the leaf grows and stays visible all season. So protection must start before the leaves unfurl.

1. Start in March and April, as soon as the tips of the shoots poke out of the soil. Protection is then most effective.
2. Remove hiding places nearby: boards, stones, piles of leaves, overgrown grass by the bed.
3. Collect slugs at dusk and after rain, or into traps.
4. Use a product based on ferric phosphate, for example Ferramol. Scatter the granules thinly over the bed according to the label, not in heaps.
5. Water in the morning, not in the evening, so that the soil surface dries overnight.
6. Choose more resistant varieties with thick, waxy leaves, such as many blue-leaved hostas. Thin-leaved and variegated ones are the most vulnerable.

An overview of gastropod species and other methods, including natural enemies, is described in the article fighting slugs in the garden.

Dividing clumps

Hostas are divided in spring, when the shoots are just emerging, or at the beginning of autumn. In spring it is easiest, the shoots are clearly visible and nothing gets broken. Lift the clump, divide it with a sharp spade or knife into pieces with several buds and roots and replant at once. Older clumps in the ground contract into a hard root ball that is hard to divide, so division is recommended after 4–5 years. If the clump is healthy and has room, you can leave it longer.

Water, feeding and autumn clear-up

On fertile soil a layer of compost or well-rotted manure around the clump every spring is enough. Mineral fertiliser is not necessary. Hosta, however, must not dry out; in a dry summer the leaves turn brown from the margins and the clump yellows prematurely. Water infrequently but generously, at the roots, not over the leaves.

In autumn, after the first frosts, the leaves turn yellow and collapse. You can clear them away at once, as decaying leaves are a hiding place for slugs. The plant is fully frost-hardy and needs no winter protection in the ground.

When the leaves do not look as they should

• Brown margins and bleached patches in midsummer – sunscald or drought.
• Irregular holes – slugs. Semicircular notches on leaf margins are made by vine weevil.
• Translucent spots, mosaic and twisting, leaf colour "running" along the veins – may be viruses, in hostas mainly Hosta virus X. There is no treatment; dispose of the plant with its roots in household waste, not on the compost. The virus is transmitted by sap, so clean tools after working with a suspect plant.
• Leaves damaged by hail or late frost – the hosta will not form new leaves that year; wait until the next spring.

Pictorial help with identifying pests is offered by the visual guide to plant diseases and pests.

Hosta and pets

According to the ASPCA hosta is poisonous to dogs, cats and horses. It contains saponins, which after eating cause vomiting, diarrhoea and lethargy. Dogs most often nibble it as young emerging shoots. If you have a puppy that chews everything in the garden, plant hostas out of its reach or in raised containers. If you suspect poisoning, call a vet.

Beware also of slug products. Older types with metaldehyde are very dangerous to dogs and cats. In a garden with animals choose products with ferric phosphate and always follow the label.

Frequently asked questions

Does hosta tolerate sun?

Morning sun is tolerated mainly by yellow-leaved and green varieties. Midday and afternoon sun scorch the leaves, and blue varieties lose their blue colour in it. It does best in light shade.

How do I protect hosta from slugs?

Start in March and April, when the emerging shoots come out of the ground. Remove hiding places, collect slugs at dusk and use granules with ferric phosphate. Growing in a container and choosing varieties with thick leaves also help.

When is hosta divided?

In spring at sprouting or at the beginning of autumn. Spring is easiest, because the shoots are visible. Clumps usually need dividing only after four to five years.

Is hosta poisonous to dogs and cats?

Yes. The ASPCA lists it as toxic to dogs, cats and horses because of its saponin content. After eating it, vomiting, diarrhoea and lethargy appear.

Can hosta grow in a pot?

It can, and it is often better protected from slugs there. Use a container 30–45 cm in diameter with drainage holes, water regularly and feed once a month from spring to August.

Why is my hosta turning yellow?

In summer most often because of drought or direct sun; in autumn yellowing is natural before it dies back. A yellow-green mosaic on the leaves may mean a virus.

Recommended products

• Ferramol slug killer, 200 g – granules with ferric phosphate for spring protection of emerging shoots.
• Garland SlugX slug trap – a trap for the hosta bed, a supplement to collecting and granules.
• BIOPON universal fertiliser 1 kg – spring feeding of hostas in containers and on poor soil.
• Planting trowel – for planting the divided pieces of a clump.

Sources

• Royal Horticultural Society: How to grow hostas
• Royal Horticultural Society: Slugs and snails
• ASPCA Animal Poison Control: Hosta

Updated: 27 September 2026