o Hostas in North America

Dr. Warren Pollock wrote this article for Diana Grenfell's new book, The Gardeners Guide to Growing Hostas. This is a book published in the U.K. and hopefully will soon be available in the U.S. Warren and his wife Ali have an amazing Hosta collection in their Wilmington, Deleware, garden. Warren writes extensively for the American Hosta Society and is one of its most active members.

         Don't forget to visit the Hosta Forum!

o The growing popularity of Hostas

According to trade information, the genus Hosta is now the most favored herbaceous perennial in the United States, overtaking Hemerocallis as the biggest seller in American nursries. The advantages of hosta are being increasingly recognized by home gardeners, the general nursery trade and landscape designers and contractors. A prime reason for their popularity is that hostas will tolerate shade; in fact, almost all of them need a degree of shade in the United States.

Hostas can grow in all but the semi-tropical and extremely frigid regions of North America, a vast geographic expanse extending from at least the US Department of Agriculture(USDA) Plant Hardiness Zone 7 in the South to Zone 2 in the North - the exact limit of their cold hardiness has not been determined. It seems that their only requirement is a period of dormancy during the winter months. Beautiful specimen clumps can be found in Birmingham, Alabama, Atlanta, Georgia; the Carolinas; Portland, Maine; Minneapolis, Minnesota; Salt Lake City, Ut; Portland, Oregon; and Toronto, Ontario. Though the season is short, hostas will grow even in Anchorage, Alaska.

Low-maintenance gardening is fashionable today, especially with busy young homemakers and senior citizens, and hostas are a relatively maintenance-free plant. They require no periodic dividing as is necessary for many other perennials such as daylilies (Hemerocallis) and irises. Slugs, snails and black vine weevils eat hosta leaves, but many people choose to ignore this disfigurement. Further, although hostas thrive best with copious watering and moderate fertilizing, these are not essential requirements for establishing clumps.

As hosta clumps become older and bigger, they become more attractive. Borders on variegated leaves become wider; depressions in leaves, such as dimples and seersuckering (puckering), become more prominent; and leaf colouring often becomes more pronounced and intense. Their handsome leaves are an attractive feature all season.

o American Hybridizers

In recent years there has been considerable activity in developing hybrids and finding sports of hostas in the U.S. This has resulted in the introduction of a large number of very attractive, new cultivars with blue, gold, green and highly variegated leaves; leaf blade sizes as small as 2.5 cm(1in) wide to huge dimensions of over 38cm(15in); leaf shapes ranging from long and lancelike to heart-shaped(cordate) or round; leaf textures from smooth to seersuckered; and leaves flat as a table top to wavy-edged to deeply cupped like a fruit bowl. For just about every gardening need, it is possible to find a hosta with suitable leaf colour, pattern, size and shape, as well as suitable dimensions and growth habit of the clump.

Tissue culture propagation (micropropagation) of hostas, pioneered in the U.S., has made available scores of species and cultivars, each in quantities of tens of thousands, very rapidly and fairly inexpensively. The time from the discovery of a worthwhile new variety to its introduction and sale in a 0.5 litre (1pt) pot in a nursery can be as short as just two years. Many large American retail nurseries and garden centres now carry a selection of two to three dozen different hostas in container sizes from 0.5 litre(1pt) to 14 litres (3 gal) - and the number of varieties being stocked each year is increasing.

Many Americans have pioneered the introduction of new cultivars. Some early ones are 'Rod Cummings, of the Bristol Nursery in Connecticut, hybridizer of the green-leaved, fragrant, lavender-flowered 'Honeybells' of H. plantaginea parentage; and John Grullemans of the old Wayside Nursery in Ohio, whose 'Royal Standard', also a green-leaved hybrid of H. plantaginea, but with beautiful, large, highly fragrant white flowers, was the first hosta to be patented (1965). To these must be added Mrs. Frances Williams, who in the mid-1930s discovered the hosta that bears her name, a gold-edged sport of the big seersuckered blue-leaved H. sieboldiana 'Elegans'. This event can be considered to be the keystone for the interest worldwide in new and colourful hostas for the garden.

In the last 25 or so years there have been many prominent hosta introducers, including; Gus Krossa, whose large upright 'Krossa Regal' with blue-grey leaves is considered a classic hosta; Robert Savory, the hybridizer of the very popular small green-leaved and gold edged 'Golden Tiara'; Peter Ruh, whose distinctive 'Paul's Glory' with yellow leaves and blue-green border is rapidly gaining popularity; Mrs. Mildred Seaver, noted for hybridizing many hostas, one being 'Sea Dream' with yellow leaves land a white margin; and Dr. Ralph Benedict, another prolific hybridizer, whose 'Crested Surf' has long lance-shaped leaves, green with a variable golden margin and distinct undulating edges.

Two people especially stand out: Alex Summers and Paul Aden. Alex Summers helped to found the American Hosta Society(AHS), served as its first president and was the first editor of the AHS Bulletin, now the Hosta Journal. Many of his imports from Japan, for example the large gold-margined H. fluctuans 'Variegated' and the small white-edged H. 'Ginko Craig', as well as many American-originated hostas such as the large gold-leaved H. 'August Moon', are now widely available and are regarded as classics.

Paul Aden has hybridized perhaps the largest number of outstanding hostas. He was among the first to see the advantages of tissue culture propagation, and has had most of his introductions propagated in large quantities by means of this technique. His very popular large-leaved hybrid 'Sum and Substance', medium-sized to large seer-suckered and cupped blue-leaved 'Love Pat', large blue-leaved 'Blue Angel' and other exceptionally fine cultivars have made him the doyen of hosta introducers.

The name of W. George Schmid cannot be omitted. His book The Genus Hosta, published in 1991, has become a standard reference. In particular, he has helped to clarify the taxonomy of both Hosta species and cultivars.

o The American Hosta Society

The American Hosta Society was founded in 1968 and today has a membership of well over 2500. The Hosta Journal is published twice a year and the Hosta Yearbook, a recent publication, is issued annually. A several-day AHS National Convention is held each summer with tours of gardens, a cut-leaf exhibit show (Hosta may be the only genus which has a competitive show where leaves, not flowers, are the entries), special lectures, and an auction where new and rare varieties are contributed by members for sale.

Supporting the AHS--and now a very important part of it--are regional and local hosta societies. There is, for example, a Midwest Regional Hosta Society which includes the Minnesota, Michigan and Indianapolis Hosta Societies. The Mid-Atlantic Hosta Society includes the Delaware Valley Hosta Society with members mainly in the Philadelphia area; the Potomac Hosta Club with members mostly in the Washington, DC, area; and the Carolina Hosta Society. Formation of these local groups, some with over 200 members, has increased markedly in recent years; it seems every geographic area has a handful of interested hosta gardeners wanting to establish a local hosta society. The attractions are that gardens with specimen hostas in the local area can easily be visited, common cultural problems can be discussed, and new varieties can be purchased at the meetings.

Several regional hosta societies sponsor one-day conferences which draw over a hundred aficionados. In the Chicago area in January a Winter Scientific Meeting is held; in Ohio in March there is a Hosta College with dozens of courses; and in the Washington, DC, area a Hosta in Focus Festival in November features photographic exhibits, video presentations and slide lectures.

o The Cultavation of Hostas

Gardening in the shade is not as easy as gardening in the sun. There are many degrees of shade, ranging from the side of a building that never receives any direct sunlight or under the dense, low covering of overlapping large tree leaves in a heavily wooded site to the open, filtered and dappled light coming through the high canopy of an up-limbed, thinly branched pine tree.

Also, the cllimate of the U.S. varies greatly between the South and the North. In the South, two hours of direct sun in the afternoon is more intense than in the North, so more shade is often required and morning sun is preferred over afternoon sun. Descriptions of hostas which say they require sun for a quarter or half of the day have little meaning unless they include information on the geographic region. In general, hostas often grow bigger in the North than in the South, given the same cultural conditions. Further, blue-leaved hostas seem to be more blue in the North, while yellow-leaved hostas often appear more yellow in the South.

British growers have noted that hostas grow bigger and the flowers are lighter in colour in the U.S. than in the U.K. The blooms of 'Halcyon' are often white or near-white in the States and greyish-lavender in Britain. Then, blue-leaved hostas seem to be bluer in Britain, perhaps due to a hazy atmosphere. Because of the generally mild climate, hosta flowers stay in bloom for a longer period in Britain than in the U.S. Also, hostas with viridescent variegation tend to fade earlier in the U.S. than those in British or European gardens, a prime example of this being H. 'Fortunei Albopicta', one of the most popular hostas in Britain but hardly ever encountered in gardens in the U.S.

Thus, the amount and type of shade and the geographical area will affect the selection, placement and performance of hostas, something that is not sufficiently recognized by many gardeners and garden designers. In general, yellow or gold-leaved hostas need some sun to develop their brightest colouring. It is frequently stated that a yellow hosta will brighten up a dark spot. This is true, but they often don't do well in such locations, finding them too shady.

The blue colouring of some hosta leaves, called pruinose or glaucous--given by a waxy, silvery coating that develops in the spring--will last longer if the plants are grown in light shade. It will also last longer in the North (because of the cooler weather) than in the South.

In general, green-leaved hostas can take a fair amount of sunlight, although in too much direct sun leaf colouring will be dulled considerably. For any hosta, too much sun, combined with lack of water, will scorch the leaves, especially in July and August.

The more sun, the more profuse the flowering. It comes as a surprise to many gardeners that there are several hostas with outstanding fragrance. H. plantaginea and the double-flowered H. p. 'Aphrodite', considered by many to have the most beautiful hosta flower, need considerable sun (and also hot weather and plenty of water) to bloom well. Their flowers are pure white with long trumpets. On the other hand, H. 'Royal Standard', with smaller, white, fragrant flowers, blooms well in fairly shady sites in both the North and South.

For variegated-leaf hostas, placement will depend on the most dominant leaf colour, usually the centre colouring. H. 'Gold Standard', with a dark green border, needs sunlight in mid-season to have its chartreuse centre change to a handsome parchment gold. In a very shady site, it becomes just a yellowish-green; given too much sun, the centre turns first to a gold and then to a light creamy white or even a near white, a less attractive colour in my opinion than the parchment gold.

H. 'June', the popular British hosta with a blue-green border, should not be grown in a very shady location. It needs considerable sun in early season to develop its brightly coloured yellow centre, and good sunlight throughout the season to help retain it.

The green-edged H. 'On Stage' also needs bright sunlight to develop and retain its yellow centre. In the South, for example Raleigh, North Carolina, this is morning sun. Further north, near Philadelphia, where I live, strong afternoon sun is required and almost all-day sun is better, provided it is kept well watered.

The axiom is: experiment in placing your hostas. If one doesn't do well in a certain location, move it to another, or replace it with a different variety. Do not be too categorical about placing a specific hosta in a specific location.

One point to bear in mind is that if your shade is from trees, the amount of shade will become more dense over the years and your hostas will not be as luxuriant; they may even decrease in size each year. Another is that some trees have greedy surface roots and will compete with the hostas for water and nutrients. Hostas don't like such competition, so if possible, plant your hostas far enough away from trees to avoid this problem.

Another solution is to plant hostas in containers. We have grown and overwintered hostas in containers for many years. They require, of course, very frequent watering during the growing season, and potting up or repotting - all requiring considerable effort. The results, though, are very rewarding as the potted hostas can be placed anywhere: on a patio; hanging from a wall; and under trees among plants in the ground. They can also be moved at any time during the growing season according to whim.

Overwintering can be a concern, depending on the geographical area and the facilities the gardener has available. Our plants are overwintered in our unheated garage. The containers are lined up on shelves along the back wall up to the ceiling; 150 pots take up only 1m (3 1/4ft) of the garage's depth.

o Recommendations

Hundreds of first-class hostas can be recommended for planting in North America if given a suitable location and sufficient water. The best of these are:

o Hosta Collections in the U.S.

At the Minnesota Landscape Arboretum near Minneapolis is the AHS National Hosta Display, featuring hundreds of varieties. Called the 'Hosta Glade', it is visited by a large number of people wanting to see mature, named varieties in an attractive setting.

Some other horticultural sites that feature hosta displays are: Dubuque Arboretum and Botanical Gardens in Iowa; Boerner Botanical Gardens in Hales Corner, Wisconsin; Herb and Dorothy Benedict Hosta Hillside at Hidden Lake Gardens in Tipton, Michigan, the Michigan State University Garden; Idea Garden at the world-famous Longwood Gardens in Kennett Square, Pennsylvania; and Pine Tree State Arboretum in August, Maine.

There are large collections of hostas in private home gardens, some having over 500 different species and cultivars. They are often on garden tours and open to the public. In the south and east, to name a few, are the gardens of Joe and Olive Langdon, Birmingham, Alabama; Robert Harris, Stone Mountain, Georgia; W. George Schmid, Tucker, Georgia, specializing in hosta spcies; Judy Springe, Great Falls, Virginia; Alex Summers, Bridgeville, Delaware; and Warren and Ali Pollock, Wilmington, Delaware.

The Midwest has an abundance of excellent hosta gardens. A few are: Van and Shirley Wade in Beltville, Ohio; Peter and Jean Ruh in Chesterland, Ohio; Richard and Jane Ware in Columbus, Ohio; James and Jill Wilkins in Jackson, Michigan; William Brinka and Basil Cross in Michigan City, Indiana; and Russell O'Harra in Des Moines, Iowa.

Hosta specialist nurseries, of which there are scores in the US, usually have a large number of specimen hostas, many of them not mentioned in their catalogues and lists.

o Hostas in Garden Design

A common fault when planting hostas is to group the young plants too closely together. Within five years they will have reached their mature sizes and be crowding each other. Except for some hosta borders, allow enough room for each clump to be recognized and show its full beauty.

All too frequently, hosta enthusiasts in North America will grow nothing but hostas, usually as borders along paths winding back and forth in back gardens and sometimes even as single-variety edging in front gardens. (One of the plants most commonly used in this way is H. 'Undulata', which was one of the first hostas to be grown in the US.) Often the entire gardening area will be used for displaying a hosta collection, resulting in a 'monoculture ghetto' (an interesting term coined by Ann Lovejoy, the American gardening writer). The well-known English plantsman Christopher Lloyd observes that 'monocultures' though simple to grasp as a concept, are unnecessarily restrictive'.

To all but the most dedicated hosta collector, large collections of hostas can be a boring scene, albeit one with very colourful foliage. To British gardeners, many hosta gardens in the States are perhaps too colourful, too garish, but America is a sunnier and hotter country that the UK, and bright, bold colours seem to suit the climate and living conditions.

In recent years, however, there is a trend to include other plants in hosta gardens, in particular those with attractive foliage all season. Combining them with hostas can be very effective, providing a pleasing foil to the hostas' foliage. Ferns, especially Athyrium nipponicum 'Pictum' (Japanese painted fern), Polygonatum odoratum 'Variegatum' (striped Japanese solomon's seal), Tricyrtis (toad lily), Heuchera (coral bells) and Pulmonaria (lungwort) are popular. Take care when planting Solomon's seal, toad lily and most ferns; they grow to a large size, and can quickly overpower small hostas.

Tricyrtis hirta 'Albomarginata' has handsome variegated leaves that blend well with solid colour hosta leaves, while the flowers of any tricyrtis are welcome vertical splashes of brigtness in late summer and autumn. Beautiful new tricyrtis, heuchera and pulmonaria cultivars are coming on the market yearly. Hellebores are good companion plants also, and small clumps of Tiarella (foam flower), with green maple foliage and usually white spring flowers, give a pleasing effect.

However, the mixed border, as exemplified in British gardens where the best features and examples of different plant categories are combined in a judicious mixture, is not often seen in American gardens. A rare exception is the gardens of James and Jill Wilkins, in Jackson, Michigan, where conifers and deciduous shrubs are used in some of the hosta beds. Blue-needled conifers, a speciality of the Wilkinses, are combined very effectively with blue-leaved hosta clumps.

In our garden in Wilmington, Delaware, Hydrangea quercifolia 'Snow Queen', a cultivar that is a great improvement on the species, is used as a background for Hosta sieboldiana 'Elegans' clumps. The hydrangea has white upright flower trusses; the hosta, scapes with near-white flowers. They both bloom at the same time, usually July. Other hostas could be used instead of 'Elegans', H. 'Blue Angel' being an excellent candidate. It has whiter flowers and taller scapes than 'Elegans'.

Information on joining the American Hosta Society and its regional and local societies can be obtained from the AHS Membership Secretary, 7802 NE 63rd St. Vancouver, WA 98662.

Information on hosta specialist nurseries are to be found in the national and local societies' publications.

         Don't forget to visit the Hosta Forum!

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