In short
- Grows in shade and partial shade - does not tolerate full sun.
- Requires consistently moist, fertile soil.
- The foliage is the main ornamental feature; the flowers are secondary.
- Prone to slug damage - protection is advisable.
- Toxic to dogs and cats if eaten.
- The blue tint of the leaves comes from a waxy bloom - sun, rain and touch rub it off, so by late summer the clump usually turns green.
- The thick, puckered leaves are harder going for slugs than the thin blades of green-leaved hostas - this is one of the less susceptible species, but in wet summers protection can still be needed.
- It emerges late, at the end of April or in May - it is worth marking its spot in the bed so the rhizome is not damaged during spring work.
Botanical data
- Family
- Asparagaceae (Asparagaceae)
- Height
- 0.4–0.7 m
- Width
- 0.6–1 m
- Habit
- Clump-forming
- Growth rate
- Slow
- Position
- Partial shade, Shade
- Soil
- Humus-rich, Loamy
- pH reaction
- pH 6–7.5
- Moisture
- Moist
- Bloom
- July–August
- Hardiness
- USDA 3a–8b
- Propagation
- By division
Characteristics
Forms dense clumps of large, heart-shaped, blue-green leaves with prominent veining. The flowers are small, bell-shaped, pale violet or white, carried on tall flower stems above the foliage. Tall flower stems are, however, a feature of the many hybrids sold under this species name - in Hosta sieboldiana itself, and especially in var. elegans, the scapes are short and the inflorescences rise only slightly above the blades or stay hidden within the clump. A mature clump reaches 40-70 cm in height including the inflorescences and 60-100 cm across, taking on a regular, dome-shaped habit. Individual blades grow to about 30 cm long; they are thick, stiff and strongly puckered between the veins - this "seersuckering" is the most reliable identifying feature of the species when set against thin-leaved green hostas. The bluish shade comes from a waxy bloom covering the leaf surface: the bloom rubs off under sun, rain and touch, which is why the clump is at its most intensely blue in spring and usually turns green by late summer - most slowly in cultivars with the thickest blades, such as Elegans. It is a perennial that overwinters solely as a rhizome - in autumn the leaves yellow and die back completely, and new shoots emerge late, at the end of April or in May, as rolled, pointed spikes, so they are caught by spring frosts less often than early-starting perennials; shoots that have already emerged can, however, blacken after a May frost, and such leaves will not regrow before the end of the season. It grows slowly, but is very long-lived and hardy all the way down to zone 3a. It needs a shady or partially shaded position and humus-rich, consistently moist soil with a slightly acidic to slightly alkaline reaction (pH 6.0-7.5), ideally close to neutral; drought is what it tolerates worst - when water is short the leaf margins turn brown and will not recover that season.
Popular cultivars
- ‘Elegans’
- A classic cultivar with exceptionally thick, intensely blue-grey and heavily puckered leaves; formally Hosta sieboldiana var. elegans, sold in the trade as a cultivar. It forms imposing, dome-shaped clumps, and the waxy bloom persists on its thick blades longer than on thinner-leaved hostas, although it too rubs off by the end of summer. It also has the shortest flower scapes in this group - the flowers barely rise above the leaves.
- ‘Frances Williams’
- A sport of Elegans: blue-green, puckered leaves with a broad, irregular creamy-yellow margin. One of the most popular hostas, but the leaf margins have an inherent tendency to spring necrosis, which the sun merely intensifies - scorched margins also occur in full shade.
- ‘Great Expectations’
- The reverse colour arrangement to Frances Williams: a creamy-yellow centre to the blade within a blue-green margin. It grows markedly more slowly than the species and is demanding in cultivation - it needs bright shade with a few hours of gentle morning sun, which colours up the centre of the blade; it will not tolerate midday or afternoon sun.
Growing and care
Watering
The large leaves transpire a great deal of water — the plant needs consistently moist soil, especially on hot days.
Fertilizing
Moderate feeding supports large, decorative leaves.
Planting
Fertile, moist, humus-rich soil in shade or partial shade; add compost before planting.
Pruning
Remove the withered leaves and flower stalks at the base.
Companion plants
Good companions
Shares a preference for partial shade and moist, humus-rich soil — a good shade-loving combination.
Similar water and light needs; the contrasting leaf texture makes for a striking pairing.
The hosta's leaves emerge later than the tulips and hide their yellowing foliage after flowering.
Bad companions
Conflicting light and water requirements make healthy joint cultivation impossible.
The evidence level indicates whether the relationship is backed by research, observation, or gardening tradition.
Diseases and pests
Small (1–3 mm) soft-bodied insects, green, black or pink, feeding in clusters on young shoots and the underside of leaves. They excrete sticky honeydew. The diagnostic feature that distinguishes aphids from other small sucking insects is the pair of siphunculi (tubular projections) at the rear of the abdomen together with a tail-like cauda; a single colony usually holds wingless forms (parthenogenetic females) alongside winged migrants that fly onto new plants in summer. In summer aphids reproduce parthenogenetically and viviparously over many generations, so the population builds up explosively; in autumn many species produce a sexual generation that lays overwintering eggs on the host, and host-alternating species move between a winter host (often a tree or shrub) and a summer host (a herbaceous plant). Feeding symptoms include curling, crinkling and distortion of young leaves, stunted growth, yellowing, and the shedding of buds and fruitlets. Abundant honeydew coats the leaves, and the sooty mould fungus that develops on it forms a black film which limits photosynthesis; the honeydew is fed on by ants, which in return defend the colony against predators. Aphids are also important vectors of plant viruses (mosaics among them), transmitting them from plant to plant even during a brief probing puncture.
Slugs and snailsSlugs and shelled snails that feed at night and after rain. Symptoms: irregular holes in the leaves and young seedlings eaten off completely, silvery slime trails on leaves and soil. The greatest damage occurs in damp, shaded spots — particularly on lettuce, strawberries and hostas. The most damaging in gardens are the slugs (which lack an external shell): the Spanish slug (Arion vulgaris, formerly described as A. lusitanicus) and the grey field slug (Deroceras reticulatum). The leopard slug (Limax maximus) can be morphologically similar to them, but it feeds mainly on decaying organic matter and fungi and may even prey on other slugs, so it is of little importance as a pest of living plants. Shelled forms — grove snails (Cepaea) or the protected Roman snail (Helix pomatia) — usually cause less damage. The body is soft, elongated and permanently covered in slime; on the head there are two pairs of retractable tentacles — the longer upper pair bears the eyes, the shorter lower pair serves a tactile and olfactory function. Slugs and snails are hermaphrodites: they lay spherical, transparent or pearly eggs in clusters, hidden in damp soil, under stones and in leaf litter. A single Spanish slug can lay several hundred eggs; both eggs and young slugs overwinter, and feeding lasts from spring to late autumn, intensifying on warm, damp nights. The damage has smooth edges and often appears in the middle of the leaf blade, not only from the margin; seedlings and transplants are sometimes eaten down to bare soil, and on strawberries and ripening vegetables the slugs gnaw hollows into the fruit. The decisive diagnostic sign is the dried, silvery glistening slime trail — no insect leaves one.
VolesSmall rodents with a stocky body, short tail and blunt muzzle, about 9–13 cm long, active all year round. They dig shallow tunnels just below the soil surface. Symptoms: gnawed roots and bark at the base of trees and shrubs (girdling of trunks under the snow in winter), eaten-out bulbs and tubers, dying plants that pull out of the ground easily, and small mounds of excavated soil with numerous shallow burrow openings linked by nibbled runways in the grass. In garden practice the name refers above all to the plant-eating field voles of the genus Microtus. Their fur is grey-brown to reddish-brown, and their small but clearly visible eyes and ears distinguish them from the mole. They breed exceptionally fast — a female produces several litters of several young per season, which mature within a few weeks — so numbers can rise sharply in multi-year cycles (outbreak years), when the damage becomes severe. They do not hibernate; the worst losses occur in late autumn, winter and early spring, when green food is scarce and they switch to roots, bark and bulbs overwintering in the soil. Under the snow cover, sheltered from predators, they gnaw the bark around the base of young trees (girdling), which after the thaw shows up as sudden wilting or death of the tree. Most at risk are young fruit and ornamental trees (especially apple trees on weak-growing rootstocks), tulip and crocus bulbs, tubers, root vegetables, perennials, and plants stored in clamps and compost heaps; daffodil bulbs, being poisonous, are usually left alone. Characteristic signs are the even, smooth tooth marks on roots and bark, roots cut off just below the soil surface, and a network of shallow runs with numerous open exits — unlike the mole, whose mounds have no entrance hole.
Toxicity
| For whom | Level | Notes |
|---|---|---|
| Humans | Mild | Eating large amounts may cause stomach upset. |
| Dogs | Moderate | Contains saponins that are harmful to dogs if ingested. |
| Cats | Moderate | — |
History and origin
Hostas gained enormous popularity in ornamental gardens during the 20th century thanks to their easy cultivation and the hundreds of cultivars bred, differing in leaf colour and size. The species comes from the moist, shady mountain forests of Japan, where it grows on the woodland floor on deep, humus-rich soils. It reached Europe in the first half of the 19th century with the wave of Japanese plants brought in by Philipp Franz von Siebold, a German physician working at the Dutch trading post of Dejima in the port of Nagasaki - his surname is commemorated in the species epithet. In Japan itself, hostas had been grown in temple and residence gardens long before their introduction to Europe. Breeding truly flourished in the second half of the 20th century in the United States, where Hosta sieboldiana - alongside Hosta plantaginea and the hybrids of the Hosta fortunei group - became one of the principal parent species of modern cultivars, especially those with thick, blue, puckered leaves.
Uses
For shady beds, edgings under trees, woodland gardens, and as a ground cover that suppresses weeds in the shade. It is planted in April-May or in September, and spacing depends on the aim: at 70-80 cm each clump keeps its regular, dome-shaped habit and stays legible as a single mass, whereas a dense, weed-suppressing cover calls for the lower end of the range, every 50 cm - the clumps then close up faster, deliberately at the cost of seeing the individual plants. It looks best in larger groups of a single cultivar and in combinations that contrast in texture: with ferns, astilbes, heucheras and sedges, whose fine or feathery leaves emphasise the bulk of the hosta blades. It also works well as a plant that masks the dying foliage of spring bulbs, because it develops only once they are finishing their growth. Under shallow-rooted deciduous trees (maple, birch) it will grow, but loses the competition for water - such positions require regular watering and a mulch of bark or compost. Under spruces and other conifers it usually fails: year-round shade, exceptionally dry soil and acidifying needle litter combine there. It suits the edges of garden ponds, but on the moist bank above the water line, not in flooded ground or in the marginal marsh zone - permanently waterlogged substrate leads to rhizome rot. It is also suitable for shady containers; in a container it needs a large volume of substrate, and in winter the container itself must be protected, because the root ball freezes through far more easily there than in the ground. The thick, long-lasting leaves are sometimes used in floristry as material for bouquets and arrangements.
Trivia
- There are over 2,500 registered hosta cultivars.
- The young shoots of the hosta are edible and used in Japanese cuisine as "urui".
- The genus name Hosta commemorates the Austrian botanist Nicolaus Thomas Host, while the Polish and German name "funkia"/"Funkie" comes from an older name for the genus - Funkia, given in honour of Heinrich Christian Funck.
- Fragrance in the genus Hosta comes almost exclusively from Hosta plantaginea and its hybrids - the flowers of this species are scentless.
- In Japan the young shoots are eaten as urui only after processing and only once the plant has been identified with certainty: poisonings occur there every year, because at the emerging-shoot stage they are confused with the highly poisonous false hellebore (Veratrum), which grows in the same habitats. In a European garden there is no reason to try it - the hosta contains saponins and is classed as a toxic plant.
Frequently asked questions
Why do hosta leaves have holes?
The most common cause is slug feeding, as slugs are the main pest of hostas. Ash barriers, beer traps or slug-controlling nematodes all help.
Does the hosta grow in full sun?
It is not recommended - the leaves, especially of blue-leaved cultivars, fade and scorch in full sun. It grows best in shade or partial shade.
How long does a hosta take to reach full size?
The hosta grows slowly - a clump usually reaches its full size 4-5 years after planting.
Does a hosta need dividing, and when should it be done?
There is no need - a hosta can grow in one place for well over a decade and looks more impressive with age. It is divided mainly in order to obtain new plants: in early spring, when the shoots are just coming out of the ground, or in September. The clump is dug up and cut with a sharp spade or knife into pieces with 2-3 buds and their own roots, and after planting it is watered generously for several weeks.
Does a hosta need covering for the winter?
In the ground it does not - the species is hardy to zone 3a and overwinters without cover, losing all its top growth for the winter; the withered leaves are removed after the first frosts. Only specimens grown in containers need protection: a root ball in a container freezes through far faster than in the ground, so the container has to be wrapped, sunk into the soil or moved somewhere cool and unheated - an unheated garage, cellar or summerhouse, where the temperature may drop slightly below zero. The point is to protect the root ball from freezing through, not the plant from cold: the hosta needs a cool dormancy, so a warm cellar or a heated room pushes it into premature growth and weakens it.
Sources
- Plants of the World Online (POWO)Database (GBIF, POWO…)
- RHS — Hosta sieboldianaInstitution / botanical garden
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