Hostas

Hostas are invaluable foliage plants which provide architectural structure to borders and come in wide range of sizes, colours and levels of variegation.

Hostas have been the most popular perennial plant grown for it's foliage in Britain for many years and are perhaps even more well loved in America. There are approximately between 40 and 70 wild species of Hosta. Originally, botanists assumed that all the plants brought back to the west were collected from the wild, but it was only later realised that many of the early introductions were garden plants and were therefore cultivated rather than wild species. Over recent years, the number of garden species developed by breeders has exploded to well over 4000, giving every possible colour, shape, size and flower variation.

The wild species are clump forming perennials by nature with green leaves which generally have lilac bell shaped flowers. They are generally shade loving plants which grow well in woodland conditions.

Various Hosta varieties

Hostas are natives of the Far East: China, Japan and Korea and have been grown in temple gardens there for hundreds of years. It is only in the most recent of times that they were discovered by the west when a medical doctor with the Dutch East India Company (Engelbert Kaempfer) made a drawing of a plant we now know as Hosta lancifolia.

It was Hosta plantaginea that made it to western shores first however in the form of seed sent in the 1780's. The first time the plants were imported on a large scale was in 1830 when another medical doctor working for the Dutch East India company (Phillip von Siebold) shipped a collection of them to Ghent in Belgium. They were grown on here and then distributed to many parts of Europe including Britain shortly after.

America had to wait a few years for it's first large imported collection by Thomas Hogg junior in 1862. Plants were sent back to the Thomas Hogg nursery in Manhattan.

Hosta 'Striptease'

The naming of hostas has always been a problem. When the first ones were brought back to the west from overseas, there was no naming system in place and names for the same plants existed both in Japanese and Chinese, and on top of that they had common and scholarly names in both languages. The first hosta to be drawn by Kaempfer was called 'Joksan, vulgo gibboosi Gladiolus Plantaginis folio'. It translates as 'The Joksan commonly known as gibboosi; the gladiolus with the plantain-like leaves. 'Gibboosi' is the Japanese name for hosta and although less so these days, the hostas common name is 'Plantain Lily'.

As the naming system was developed, so the problems multiplied with hostas names. Hostas classification in the plant kingdom has been just as difficult but the absolute way to identify a hosta and it's cultivated forms is by it's flowers since it's leaves my change with differing regional variations.

Propagation

Commercially, hostas are grown by means of micropropagation (tissue culture) in a laboratory but it is easy to increase your hosta numbers at home by either sowing seed or division. It's worth noting that division however is the only way to guarantee that the plant is the same as the original.

By Division

The first method is to slice them in much the same way you would slice a circular cake, using a sharp knife dipped in fungicide beforehand. The new surfaces should be also dipped in fungicide to prevent rotting before being potted up or planted somewhere else to grow.

The second way, which I personally find easier is to divide them by digging up the whole clump and either using two forks back to back to prise them apart or teasing out each individual fan of leaves by hand and re-planting.

Generally, hostas are best divided in early spring just as the new sprouts are forming above ground. It can be achieved in early Autumn if the weather is mild as the plants then can establish again before the onset of winter. It is possible to divide in summer provided that the leaves are cut off first and are given plenty of water afterwards. Do not divide them during periods of frost or drought however.

By Seed

Hostas seed well naturally on some soils, without any interruption from man. The resulting plants tend to have little in common with their parent parents and have limited garden value.

The seed pods should be picked as soon as they start to open, and placed in an envelope until they pop out. It is important to separate the seeds from the husks, stem and other litter at this point as fungus may get into the storage and destroy all seeds. They should be ideally stored in an air tight tin in a fridge until spring. Seeds last for about 6 months. They are frost hardy, but they must have protection from slugs and snails as they will be eaten!

Cultivation

The process of planting hostas is like painting your living room. The more time spent preparing the soil, the better the plant will be. They are best planted in spring whilst the soil is warm or in later autumn as long as it is still warm.

• Dig the hole the size required (around twice the depth of the plant).
• Break up the soil at the bottom of the hole.
• Fill the hole up to half way with alternate layers of well rotten manure and original soil dug from the hole.
• Tease out the roots from the root ball after removing the pot.
• Place the plant in the hole with the crown of the plant level with the original soil level.
• Firm the plant in with your heel.
• Drench the plant in water, ideally by means of using a hose trickling rather than a bucket full of water.
• Mulch around the plant with well rotted manure or over mulch.

In terms of location, each hosta needs a specific amount of light or shade to produce it’s ideal leaf colour and shape. Most need a dappled shade from a trees branches for example, but generally, hostas with white margined leaves need more shade than yellow margined or centred leaves. Green and yellow leaves or white variation in the centre of the leaf prefer a few hours morning sun (providing they have plenty of moisture) and grey leaved varieties loose their glaucous colour if exposed to direct sunlight. The bottom line is after planting, keep an eye on them and if they show signs of not liking their new home; move them!

Hosta albomarginata

Hostas planted in pots are best grown in soil based potting medium like John Innes No 3. Smaller hostas prefer peat based containers however. They should be re-potted every 3-4 years as they will eventually exhaust the potting medium, giving a good chance to divide the plants and re-invigorate them.

Care

Hostas need a constant supply of moisture in the soil to make healthy large plants. If watering from the surface, water beneath the leaves using a watering can or hose pipe. Water early in a morning rather than evening as this attracts slugs and snails. Medium sized varieties need to be watered every 2 or 3 days whilst larger species need water almost every day from one source or another, especially in high summer. Work on approximately 4.5 litres per plant, but some bigger species which are fully grown can take 12 litres a day.

Feed approximately every couple of weeks from late spring to mid summer. Apply a weak solution of balanced fertilizer with N, P and K along with the usual trace elements. Apply one application of high N fertilizer in early spring. It is advisable to add a nitrogen rich fertilizer to any organic mulch as they will need to be replenished on a regular basis.

Mulching hostas in autumn or early winter is beneficial to the plant (although it can be done at any time of year). It should be replaced annually however, and make sure that the centre of the crown is not covered as the plant may rot when the mulch rots down, and leaves tend to get distorted as they first emerge.

Soil

Hostas will grow in many reasonably fertile soils provided it will hold moisture but is well drained, especially if enriched with well-rotten organic material like garden compost. Clay soils make it difficult for soils to establish and therefore they will take longer to establish. Sandy soils are better but these do not hold much water so soil improvement is best for both clay and sandy soils. Hostas don’t mind chalk too much although they are not happy on thin soils over a chalk base as it cases then green leaves to turn yellow.

Shelter

The leaves easily damage from strong winds and also loose far more moisture this way so keep out of the way of strong winds


Pests and Diseases

Everyone that has ever tried growing hostas knows that it really is pretty easy, apart from the dreaded slug and snails. Garden centres have vast selections of cures for these insatiable predators, but all are limited in effectiveness Nematodes, growing them in pots, and going out every night with a bucket and torch are my only real options for less eaten leaves!

Slug and snail damage to hosta leaves

Vine weevils

A problem in both adult and larvae stage. They generally like the conditions in pots better than open ground.

Necrotic Spots

Tiny spots can appear on the leaves in spring. These can be brown and with a very small hole in the middle and are more frequent when the weather is cold and damp. Fungi can then infect the leaves quite easily. The return of warmer weather and better circulation of air will usually prevent it's return.

Viral infections

Yellow mottling on the leaves, usually on just part of the leaf than all of it but fading in midsummer is a sign of a viral infection. Other types of virus cause the leaves to distort but do not get confused with drought damage. There is no known cure and current advice is to dig up and burn the plant.

Melting out

This is physiological damage occouring to leaves of some hostas (mainly those with white, central variegation. Brown marks appear on the centre of leaves which eventually will dry up and fall away leaving behind a hole.  Damage like this usually occurs to younger plants exposed to strong sunlight but can in some varieties appear in intense shade.

The American Hosta Society
http://www.hosta.org/

The Hosta Registry of the American Hosta Society
http://hostaregistrar.org/

The British Hosta and Hemerocallis Society
http://www.hostahem.org.uk/

The Hosta Library
http://www.hostalibrary.org/

 
Where to see hosta's:

The nearest places in the North west to see a national collection of hosta is:

Tetraploid varieties

Contact: Mr T Saville
12 Burnham Close
Cheadle Hulme
Cheadle
Cheshire
SK8 6DN

Tel: 0161 485 6630

E-mail: americanhostas@breathemail.net

By appointment only

and

Large leaved varieties

Leeds City Council: The Hollies Park (Part of Meanwood Valley)

Contact: Mr D Lockwood
National Collections Co-ordinator
Leeds City Council
7th Floor West
Merrion House
Merrion Centre
Leeds
Yorkshire
LS2 8DT

Telephone: 0113 3957400

Outside the area, HRH The Prince of Wales, has the national collection of giant and larged leaved hostas at Highgrove within the natural setting of a stumpery.