The genus Hosta is the essential and could be the predominant perennial for your shade garden. Dare to compare Hosta with any other group of serviceable garden plants. Hosta has all of the positive traits such as low maintenance requirements, hardiness, shade tolerance, and beauty. They are native to China, Japan and Korea and have been grown in the USA for about 150 years. During that time many varieties have come and gone. Currently nearly 1,000 cultivars have been officially registered and another 1,500 have not been registered, but have been identified, described and written about. (See references at end of article.)
Hostas provide you with an endless variety of size, color, texture and shapes and they are excellent to blend with other genus or even to have a specialty Hosta garden. They remain attractive from spring until frost. Hosta flowers borne on scapes (like daylily) range from dark purple to white and some are even striped. Current breeding work is putting more emphasis on better flowers, and in particular fragrant flowers. Beginning in June they bloom through September maybe even till October, if various cultivars are planted. Known principally for their foliage, Hosta leaves range from miniatures to plants that have leaves much larger than a dinner plate with textures of smooth to leathery to seersucker. Some age slowly, taking five years to fully mature but the majority mature nicely after three years.
No matter your landscape or garden need, there is a Hosta waiting to fill it in a picturesque manner. Hostas will provide foliage contrasts unequaled by any other genus of garden plants and they will continue to thrive for many years. They can be used as a magnificent specimen garden centerpiece, border plants, prevent soil erosion, and anything in between. Best of all, Hostas improve with age to form beautiful clumps to mounds three feet across.
Hosta colors can be solids of green, blue, gold, almost white or with mixed colors with edge or center variegations.
A few notes on color:
- Blue Hosta – Blues need darker areas of shade to hold their deep blue color. To get the best blue color, limit overhead watering (use a soaker hose), provide good light without direct sun (or they will turn green) and be careful with chemical applications as some solvents can dissolve the natural waxy leaf coating. Most important of all, start with a very nice blue cultivar. Blues are the easiest color to blend in. They look great next to bright annuals, such as impatiens, add contrast next to gold Hosta and provide a darker shade next to popular greens. They will fit in most anywhere!
- Yellow to Gold Shades of Hosta – The fantastic thing about yellow to gold shades is that they will brighten up the darkest corner. Do not overdo it, though. One gold spark of Hosta will draw your eye to that spot but a scattered group here and there can look confusing. Many gold Hosta hold their color best with at least dappled light. Generally the thicker the leaf substance the more sun they need to help keep their rich gold color. Gold Hosta seem to hold up best in brighter light without sun-burning (full sun in heated conditions can deteriorate leaves from outward in) and used in this way look best next to bright colored flowers. They also blend in nicely with Hosta with gold-margin variegation, bringing out the bright gold.
- White-Margined Hosta – Used effectively when planted sparingly in your landscape to provide diversity with solid colors. They provide pleasant eye appeal when planted next to soft – colored annuals or perennials with pinks and mauves.
- Cream to Gold-Margined Hosta – Like the white variegated types, these are best used next to solid colors. Unlike the white variegated types, however, the gold margined Hosta are most eye appealing with bright or “hot” color combinations. Solid gold Hosta, being bright, look very attractive next to them. Perennials with yellow flowers complement them.
The following growing hints provide you with a core of working knowledge upon which you can build as you become more interested in the genus Hosta.
When to Plant Hosta
The best time to plant Hostas is from mid-May to mid-September, although most people plant Hosta in the spring. Hostas grown in pots grow better than bare root crowns; however, excellent success is possible with bare root Hostas if you follow the suggestions below.
Where to Plant Hostas
By now you realize that Hostas usually prefer a semi-shade location. Some morning sun is good, but avoid the hot mid-afternoon sun. Bear in mind, the more sun, the more water may be necessary. Select a site with good drainage (deep soil permeability). The soil should be open and loose and able to retain moisture. Organic matter such as pine fines, spaghnum peat moss or compost should be mixed into the soil. A mixture that works well is 1/3 native soil (the stuff in the hole), 1/3 peat humus or pro-mix, 1/3 pine bark fines. When you site your Hosta try to get the maximum contrast. This can be done with more than just color. For example, a large tree trunk in the background for a yellow Hosta works well, so do rock and brick walls. Texture contrast can be achieved with fine foliage plants like ferns and astilbe.
How to Plant Hostas
Prepare a hole, about the size of a half-bushel basket to that of a full size bushel basket, depending on the size of the Hosta clump. Plant the center of the crown just slightly below the soil surface. The crown is where the roots and leaves join together. Water in slowly and thoroughly and mulch sparingly. The amount and type of fertilizer is subject to much debate among hostaphiles. The norm seems to be an application of around 10-10-10, three to four times per year. For the lazier gardener, you can use a slow release (and more costly) fertilizer such as Sierra Blend or Osmocote one time in early spring and perhaps a boost in mid-season with Miracle-Gro. Remember to account for the fact that your Hosta will be growing larger. A common mistake is to plant too closely, and end up with clumps that are not shown to their full advantage. As noted earlier, it takes about three to five years for a fully mature Hosta to develop, although they are very beautiful from the second year onward. A good rule of thumb is an area 3′ x 3′ for the large cultivars and 1′ x 1′ for the smaller types.
Water well especially the first growing season. After that, it is essential that Hostas receive a minimum of one inch of water per week (either by irrigation or rain) during the growing season. After the leaves wither and die from frosts, trim the leaves off. If you leave the bloom scapes about two inches long you will know exactly where you planted your Hosta. Clean up your Hosta area after full killing frosts. This will help sterilize the top of the soil and plant tips and will help to eliminate slugs and other critters that congregate and over winter in the dead foliage. For the new and young Hosta, a mulch of white pine needles (get these from your neighbor’s tree) over the new crowns, is a good idea.
Insect and Disease Problems for Hostas
Hostas are tough plants! Only a few problems exist. The only significant pest is the dreaded mollusk—the slug— ugh. They prevail in the rainy season but they are a nemesis almost anytime. If you see holes in your leaves, you have got slugs or possibly snails. Slugs prefer moist, dark areas so it is important to avoid watering that will leave your plants wet before dark. Sanitation is a major key in control of these guys. Finding the slugs and removing them along with removal of debris from Hosta beds is important. Slug bait is also an effective control. The chemical of choice is metaldehyde. It comes in the form of a pellet or a viscous liquid (squeeze drops from spout on bottle). Some effective non-chemical approaches are stale beer in a pie tin, wet newspapers, diatomaceous earth, wood ashes and three inch-wide copper strips (expensive but permanent). The beer and newspaper methods are traps so the slugs can be removed. It is nice to know that, in general, the older a plant gets the more pest resistant it becomes. Also, many cultivars are being bred for greater resistance to slugs. Note: After a hard rain you need to reapply whatever slug stuff you choose. If you see notches on the sides of leaves and stems (leaf petioles) then you may have black vine weevil. Rare instance of virus and foliar nematodes are insignificant to date. Most quality Hosta growers destroy plants with these two problems instantly, at their nursery, and thus present no apparent danger to the retail buyer.
Another area of controversy. Some say it is not necessary and you should leave the clump to make a striking statement. The other camp, feel Hostas should be lifted and the clump divided on a regular basis every 3-4 years. GRAINETHUMB takes the view that you can divide your Hosta if it has outgrown the space you allowed, you want to trade with someone, or for the purpose of propagation. If you feel it is time to divide your Hosta, a good time to do so is late summer while the Hosta still has some leaves. Then you can see how much you want to remove, but a Hosta can be divided at almost any time. Some even prefer spring when the eyes are just starting to come out of the ground.
- The Hosta Book, 2nd ed. Compiled and edited by Paul Aden, 1990, 133 pp, 209 color photos, $17.50, paperback.
- The Genus Hosta by W. George Schmid, 1992, 480pp, 208 color photos, 200 b/w photos, $55.00, hardbound.
- Hosta: The Flowering Plant by Diana Grenfell, 1991, 240 pp, 49 color illustrations, 27 line drawings, $37.50, hardbound.