Synonyms

Hosta nigrescens 'Krossa Regal'

Family

Asparagaceae

Common name/s ?

Plantain lily 'Krossa Regal', Corfu lily 'Krossa Regal', day lily 'Krossa Regal', hosta 'Krossa Regal', Giboshi 'Krossa Regal' and funkia 'Krossa Regal'.

Skill rating

Easy

Origin

Asia (China, Japan and Korea).

Type of plant ?

Deciduous herbaceous perennial.

Hardiness zone ?

RHS zone

Hardy

EGF zone

H4

USDA zone

3-9

Eventual size

To 70cm height by 75cm spread.

Growth rate ?

Moderate, will reach full size in 2 to 5 years.

Shape it grows into

Forms large clumps of foliage with flowers on taller stems.

Season/s of interest

Flowers in summer. Foliage interest from spring to autumn.

Where to grow it

Happiest in part shade.
Prefers well drained to moist soil.

Hostas prefer fertile (nutrient-rich), clay or loam soil which is moist but well draining and of a neutral to acidic pH (although they will grow on alkaline soils if these can be enriched). They need a sheltered position away from drying winds, ideally a north or east facing spot.

While they prefer part shade, they can cope with shade, but for the best colour they like more sun early in the season and more shade later on.

Hosta 'Krossa Regal'

Features

Clumps of large, blue/green leaves are held up on tall stems. Taller spikes bear racemes of pale violet flowers in summer.

What to use it for

Hostas are good for beds and borders, including for ground cover and edging. They work well for underplanting trees and large shrubs, trees with deep roots (eg oaks) in particular. Hostas may be planted in containers and are useful for flower arranging, thanks to the tall stems bearing the flowers. The striking foliage works well with both informal, cottage style planting schemes and in more formal or modern design gardens.

How to look after it

Mulch well in the spring, ideally with leaf mould. Over the hotter months the soil should be kept moist, though not wet, although hostas can survive short periods of drought thanks to their roots retaining water.

How to prune it

Remove any spent foliage and cut the dead foliage back down at the end of the season. Some growers prefer to remove the flower stalks as they develop so they don’t detract attention from the foliage.

How to propagate it

Can be propagated by division, but newly planted plants should be left undisturbed for around 5 years before dividing. Division can then be done a maximum of once every five years. Divide your hosta in spring, breaking dense clumps apart with a spade, looser ones by hand, into single buds if required (so long as each has some roots attached). Soak the roots of the divided plants for one minute before re-planting in pots or a nursery bed, to minimise the transplantation shock. Divided single buds can be ‘topped’ to encourage more shoots to grow, forming a larger crown. To ‘top’ the buds, scrape the soil away from the base of the bud in spring, as it begins to grow, and wipe the base clean. Then make a small, vertical cut, through the base of the shoot (where the crown is forming) and apply hormone rooting compound before re-covering the crown and watering well.

Seeds can also be collected in autumn from the ripe fruits (legumes) and sown at 15°C, then grown on in a cold frame (in fact, most hostas tend to self-seed freely). The resulting plants should flower in 2 to 3 years. As this is a cultivar it won’t come true from seed, but you may find some interesting and pleasing variations occur.

Common problems

Slugs and snails are the main enemy of hostas, gorging themselves on the luscious leaves. Rabbits and deer can also be a problem, as can vine weevils and leaf eelworms. ‘Hosta virus X’ is increasingly becoming a problem.

Other useful information

Hostas were first brought to Europe from Asia in the 1800s and arrived in the USA shortly afterwards. The genus Hosta was named after Austrian botanist Nicholas Thomas Host (1761 – 1834).

This hosta has been given the Award of Garden Merit by the RHS and also the Eunice Fisher Distinguished Hybridizer Merit Award by the American Hosta Society. It was originally brought from Japan and cultivated by Gus Krossa and was formally registered in 1980.