Hostas

Hostas are among the most popular of garden plants, but unlike most of the others at the top of the list, hostas are there mainly because of their foliage. Alas they are herbaceous and die back during the winter, but they are with us for the other three seasons of the year, providing a mixture of excitement and practicalities. The excitement comes from the huge range of different shapes, colors and textures of the leaves and the diverse ways in which these can be used. The practicalities come from the fact that hostas are good 'sensible' plants. They can create a backbone for borders throughout the seasons and are dense enough to provide ground cover in shady areas.

Hostas are not a very big genus as some plants go. There are only about 40 or so species, but on the other hand there are countless thousands of cultivars, most of which have been bred in America or Japan. In the wild they originate from eastern Asia: from China, Japan and Korea. They are basically woodland plants that like to grow in light shade. The marvel of hostas is that they will grow in moist, boggy conditions as well as very dry situations. The size of hostas varies considerably from tiny plants not more than a few inches high to enormous clumps up to 2 feet tall (or more if you include the flower stems). An individual plant will form a dome of foliage, as it ages so it expands and the dome grows broader. When several hostas are planted near each other the plants merge to form a continuous and effective ground cover.

Nearly everybody that grows hostas does so for their foliage. The shapes of the leaves vary from thin narrow ones to those which are almost round. The surface is often heavily pleated, creating a play of light and shade. The margins also vary from flat to wavy. Their texture can vary from the shiny to dull.

There is a tremendous variation in color, although the range of colors is relatively limited. As with all foliage the basic ingredient is green, there is an enormous number of different greens, from light green to dark green. The textures of the leaves, in turn, affect these colors: a shiny dark green is quite different from a dull dark green.

The influence of white and cream and yellow and gold changes the leaves completely, they suddenly become much more alive. The green is never lost (if it was the plant would not be able to photosynthesize and produce food); it is always hovering in the background. In the main the green leaves are either margined with white or yellow or the green itself is the margin and the variegation is in the center. The variegation can be either regular or irregular. The leaves are rarely splashed with irregular splashes.

Sometimes the whole leaf is yellow or gold, but there is always some green in the color, and even if the leaves open up as a pure color, they soon begin to become tinged with green. The only real color break is that some hosta leaves have a blue coloration, admittedly a greenish blue but blue nonetheless. Although green leaves can also be glaucous (covered with a sort of fine greyish powder) it is most notable on the blue forms. This gives them an added attraction.

Hosta flowers are often overlooked in the enthusiasm for the foliage; indeed some growers even cut them off. However, flowers are a very attractive part of the plant. The generally leafless stems are thrown up well clear of the foliage, each bearing a series of pendulous, lily-like flowers. The flowers vary from white and lilac right through to quite a dark blue. They do not flower very well in dark conditions, but will do so in light shade. The light coloration of the flowers means that they stand out beautifully when many other flowers fade into the shadowy background. Flowers appear from midsummer onwards.

Hostas are very valuable in the garden. Apart from anything else they simply look good and fit in with so many other plants (for example irises, tulips, roses). On top of this they make valuable, attractive ground cover. One of their most important contributions to the garden, is that they are superb plants for shady conditions, either under trees or in open shade against north walls.

One aspect that is often overlooked, is that hostas grow well in pots and other containers. These can be placed in full sun if they are kept well-watered, but are best used in shady areas where it may be difficult to find other subjects for containers. Although clumps can be grown in the border for many years, it is necessary to repot those grown in containers every three or four years to keep them looking fresh and at their best and prevent them becoming too pot bound.

The cultivation of hostas is very straightforward. They do best in a typical moist woodland soil, that is one that includes plenty of well-rotted organic material. If possible treat the whole border but if compost is in short supply, just add it to the area around the plant. Hostas grow best in light shade but can also be grown in full sun, although it is then essential to keep the soil moist (they are more tolerant of drought in shade). Another advantage of light shade is that over-hanging trees or shrubs offer some protection from hail. This may seem trivial but in areas prone to summer storms this may be of importance, as the foliage can be shredded in seconds by a sudden downfall. Wind can also be a problem, especially if laden with sea salt. Again shrubs and trees will afford protection, but it may be necessary to provide extra windbreak in extreme conditions.

History of hostas The anatomy of hostas Propagation of hostas Cultivation of hostas Pest and diseases of hostas Hostas species & cultivars

The best times for planting are in fall, while the soil is still warm enough for the roots to become established, or in the spring as things are warming up. Always plant to the same depth as they were in their pots. After planting, water well and mulch to preserve moisture. Water daily, if necessary, for a week or so until the plant becomes established.

One of the most serious problems for any grower is slugs and snails. These can ruin the appearance of any hosta in a single night. Going out at night with a torch and collecting up any you can find will reduce the population. Slug bait is an option for those who do not mind using chemicals, indeed it is the only sure way of totally protecting the foliage. Various other traditional methods are often recommended, such as surrounding plants with ashes or grit, but these rarely deter the determined slug.

The other problem that besets many growers is that a late frost can turn the emerging leaves to mush, from which the plants will not fully recover until the following year. The only solution is to keep an eye out for frosts and cover your hostas with fleece, old blankets, sheets, towels or anything else you have to protect the plants. Growing under trees or shrubs will give some protection and it will only be severe frosts that will be a problem here. General winter protection may be needed in cold areas.