In the last decade, few plants have caught the attention of gardeners as much as shade-loving hostas.  Easy to grow and propagate, hostas offer graceful forms and radiating patterns in a wide range of colors, textures, shapes and sizes.

Native to Japan, China and Korea, hostas are hardy perennials grown primarily for their beautiful foliage.   Introduced to Europe in the late 1700s, hostas came to the United States in the mid 1800s and were often called plaintain lilies or funkia.  Easily maintained and widely available, today's nurseries and catalogs offer more than 4,000 cultivars, of which 500 are probably distinct and garden-worthy.  The last few years have witnessed a substantial rise in the quality and quantity of new hosta introductions, or cultivars.  These "cultivated varieties" are developed for desirable or improved features, such as plant form, size, bloom, leaf color, variegation or pest resistance.

Hostas are hardy for Colorado's climate and--when roots are established after the first year or two--have no problem surviving harsh winters, even without snow cover.  Although new hosta plantings should be mulched for protection from summer's heat and winter's dryness, most gardeners consider hostas similar to daylilies, in that they are usually foolproof plants.  Plant and water them and soon they're on their own.

Usually symmetrical, hosta plants take fountain, mounded or upright forms.  Their sizes range from two-inch miniatures, with leaves like thumbnails, to platter-leaved specimens fanning out over four feet.  Just when midsummer mainstays are waning, hostas send up vertical scapes that open into a series of delicate, lily-like blooms.  Depending on the variety, hostas will bloom between June and October and last for several weeks.  The white-to-lavender flowers are fragrant in some cultivars, motivating hybridizers to breed larger and showier flowers. Some newer plants may have 50-75 blooms on each flower scape.

Shade/Sun Requirements

While hostas are regarded as shade plants, they appreciate some sun.  For the best performance, hostas prefer light shade or a few hours of morning sun followed by afternoon shade.  Certain cultivars will tolerate some afternoon sun, although full afternoon sun can burn leaves in the summer, especially the variegated varieties.  Blue-leafed hostas generally require shade, while gold, yellow, and white-leafed hostas can tolerate more sun.

Soil Preparation

Hostas grow best in rich organic soil, a rarity in Colorado gardens.  When planting new hostas, encourage proper drainage by adding compost and adjust soil pH to the recommended range of 6.5-7.5-slightly acidic to slightly alkaline. Colorado soils generally alkaline, the addition of organic matter such as Canadian peat moss and cottonseed meal will help to lower the pH.  When making a new hosta bed, cultivate to a depth of 12-16 inches.  Apply six inches of organic matter-compost, leaf mold, well-rotted manure or Canadian peat moss-- and till into the new bed.  These additions also serve to raise the bed, which will improve drainage.

Holes should be dug at least a foot deep. The width of the hole should be one and a half times the expected mature size of the clump. Most hosta roots will grow and spread horizontally, so a large, wide hole is best.

Planting

Hostas may be planted from mid-May to mid-September, although spring is recommended.  Remove the plant from its container, loosen and untangle the roots.  If roots are compacted, make several vertical cuts in the root ball with a knife or sharp spade. The area where leaves and roots meet should be at ground level, matching those previously established in the container.

Hostas ordered from catalogs may arrive as bare root plants. Soak the roots in tepid water for about 30 minutes prior to planting.  Form a small cone in the bottom of the hole, spread the roots over it, add the amended soil and water thoroughly.

Remember that your hostas will be growing larger.  A common mistake is planting too closely, which results in crowded lumps not shown to full advantage.  A rule of thumb is 3' x 3' for large cultivars and 1' x 1' for smaller types.  A layer of mulch will help keep roots at an even temperature and prevent competition from weeds during the two-five years that its takes plants to completely fill in.

Fertilizer

With several choices of fertilizer--including liquid, granular, and extended release granular--gardeners must weigh the benefits and limitations of each.  Follow label directions carefully for the application rates of each type.  Be careful not to apply fertilizer on new growth or leaves.  All fertilizer applications should be discontinued by late July.  Hostas need a hardening period prior to cold weather.  Any tender new growth of late summer may be lost to the first frost.

A balanced granular fertilizer such as 10-10-10 or 5-10-5 can be applied early in the spring, followed by an application six weeks later and mid-summer--typically early April, mid- to late May, and mid-July.

Water

Water is important for optimal growth, though once established, hostas require little watering and won't need dividing for many years.  An inch of water each week is recommended, and can come from rain, irrigation or hand watering.  Deep watering will ensure good root development.  The greatest growth usually occurs when water exceeds the minimum recommendation.  Watering hostas on a regular basis-and early in the day--is recommended, since their broad leaves contribute to a very high rate of transpiration.

Drooping leaves signal that plants are drying out.  Leaf ends may occasionally appear to be burned, a symptom of insufficient water making the distance from roots to tips.

Propagation and Division

Hosta can be divided any time during the growing season, although most gardeners try to plant hosta in the spring and divide in the summer.  Division can be done as late as August, planting at least 30 days before the first fall frost date. Warm soil and higher humidity at this time promotes better root growth and plants may show a little growth spurt at this time. The later in the season a hosta is planted, the more important it is to provide adequate water. Lift the entire hosta clump and wash soil from the roots, if possible, to make it easier to see where to cut and divide.  Some of the larger leaves on a division may be cut back to reduce water loss.

Pests

Hostas have few diseases and their only significant pest is the slug. Although slugs will not destroy the plants, they often leave unsightly leaves.  Fortunately, slugs can be fairly easily controlled with baits and traps.

Slugs are nocturnal foragers and eat small round holes in leaves.  By starting an abatement program early in the spring, slugs may be easier to control.  Look for silvery slime trails in garden beds to determine if slugs are present. Thin-leafed hostas and those with leaves growing close to the ground are most susceptible to slug injury.

Chemical slug pellets and baits that contain metaldehyde are widely available commercially, although label directions must be followed carefully.  Newer baits containing iron phosphate, less toxic to animals and birds, are also demonstrating success in slug control.

Beer traps are widely used, albeit with moderate success.   Small shallow containers, such as jar lids, are placed level with the soil and filled with beer. Attracted to the brew, slugs crawl in and drown.

Other methods offer limited success.  Traps of wet newspapers may be laid on the ground overnight.  Slugs assembling under this damp refuge can be folded into the trash or sprayed with a 10-20% solution of ammonia and water.  Slugs are fatally irritated by gritty diatomaceous earth, which is scattered on soil surfaces.  This must be reapplied after watering or rain, since it easily dissolves.

Maintenance

Trim leaves that wither and die after frosts.  Some gardeners enjoy the winter interest of the dried flower scapes, while others clip to a few inches as a marker of the plant's location.  Cleaning hosta areas after hard frosts will help to eliminate slugs and other pests that congregate and overwinter in dead foliage.

Companion Plants

Before hosta leaves emerge in late spring, early blooming bulbs and smaller perennials can put on their show in the same space.  As bulb leaves begin to dry, hostas swell and unfurl.  Recommended companions include snowdrops, crocus, tulips, daffodils, trillium, and anemones.  Ferns, especially Athyrium nipponicum 'Pictum' (Japanese painted fern), astilbes, hellebores, dwarf conifers, heuchera and pulmonarias are also good companion plants, provided they are given adequate space.  In summer months, annuals such as impatiens, begonia, and coleus make attractive companion plants.

For more information visit the American Hosta Society's website at www.hosta.org

Popular Hosta Cultivars

1. Hosta 'Sagae'-72" wide x 36" tall.  Leaves are large (13-14" long x 10" wide), thick textured, and chalky blue-green with neat gold margins. Flowers are violet.

 
2. Hosta 'Sum and Substance'-60" wide x 30" tall.  Leaves have a glossy texture and grow upright. The chartreuse leaf color changes to gold with exposure to more sunlight. Very pest resistant.  White bell-shaped flowers appear in late August.

 
3. Hosta 'Great Expectations'-58" wide x 29" tall.  Leaves are round and puckered with good substance. They have an extremely wide, irregular margin of blue and green enveloping a light yellow-cream center. Flowers are a dense mass of white blooms.

 
4. Hosta 'June'-36" wide x 15" tall.  Leaves are 6" long x 4" wide, with a nice gold center and blue-green margins. The leaves have very thick substance.

 
5. Hosta 'Patriot'-50" wide x 23" tall.  Green leaves have bold white margins that are 1/2 to 1" in width. The color of the margin will turn from creamy yellow in May to white during the growing season.

 
6. Hosta 'Paul's Glory'-55" wide x 25" tall. The yellow leaves have a blue-green margin. The centers of the leaves are chartreuse in late May, then slowly change to bright gold by mid-July. With more sun, the gold lightens. The blue-green margin in early June becomes dark green in mid-July. The flowers are white and bell-shaped.

 
7. Hosta 'Gold Standard'-3' wide x 18" tall. This is a vigorous grower. The leaves have a dark green edge with a golden center. The pale lavender flowers bloom in mid-July to mid-August.

 
8. Hosta montana 'Aureomarginata'-6' wide x 27" tall. The large leaves are 15" long x 8" wide. The leaf margin is bright gold with a green center. The plant holds its color all season.

 
9. Hosta 'Krossa Regal'-6' wide x 36" tall. The heavy, leathery, blue-green leaves are slug resistant. It is the most used, most planted, large blue hosta used today. It has continually ranked near the top in U.S. popularity for years.

 
10. Hosta 'Fragrant Bouquet'-26" wide x 18" tall. The leaves are light green with a yellowish-white margin. The large, funnel-shaped, white flowers are fragrant.

 
11. Hosta 'Guacamole'-54" wide x 24" tall. The leaves are 11" long x 8" wide, shiny, and yellowish-gold with a dark green, wide margin. The leaves are very shiny both above and below, and are moderately folded with a smooth margin. The flowers are near white and are very fragrant.

 
12. Hosta 'Blue Angel'-85" wide x 36" tall. The leaves are huge (18" long x 12" wide) and have heavy substance. Flowers are a glossy white.

Hosta Vocabulary

solid  - Single leaf colors come in ranges of blue, gray, yellow, gold, or chartreuse.

variegated - Variegated leaves include a combination of lighter and darker shades.

medio variegated - Leaves show a light color in the center of the leaf, which may be white, gold, yellow, or light green.

marginally variegated - Leaves show a light color on their edges.

rugose - Thick, stiff leaves with heavy substance; considered to be somewhat resistant to slug feeding.

Q: I have started a compost pile. Should I put in all my garden debris?

A: It is great that you have started composting but I do have some advice for you. Don’t put any plants that suffered from bacterial or fungal infections in the compost. Most home compost piles do not get hot enough to kill the fruiting bodies. These could infect new plants when you use the compost in the spring. It would be safer to throw away any infected plant material.

Q: What can I do with my tomatoes if we get a hard freeze before they ripen?

A: Fried green tomatoes are great to eat but if you still have too many green tomatoes, try  wrapping them individually in newspaper and putting them in a cool place.  Check them every 3-5 days and as they turn more orange you can set them on the counter till they turn red or put them in the kitchen window.  If the tomatoes are still green rewrap them and keep checking on them.  When I did this last year I had garden tomatoes till the end of October.

Q: I have a Dark Knight Spirea that I really enjoy. Will I need to cut it back?

A:Yes, cut it back to about four inches in either late fall or early spring.  Some people enjoy the "skeleton" of this shrub through the winter as it adds interesting winter texture to the garden.

Shop early for the best selection of bulbs for next year’s spring flowers.  If you are tired of just tulips and daffodils, try something a little different this year.  Look for Greek windflowers (Anemone Blanda), rockgarden iris (iris reticulata), or Glory of the Snow (Chionodoxa).  These are small bulbs – similar in size to crocus - but will bloom early before everything else is up in the garden.

Looking for an easy way to get those sunflower seeds separated from the heads?  Make a “sunflower harvester” from 1” x 2” lumber and wire mesh or hardware cloth with 1/2” openings.  Build a frame from the lumber large enough to set over a pail or tub and tightly attach the mesh to the frame with staples.  Rub the sunflower heads vigorously across the wire mesh and the seeds will fall into the bucket.

Dahlias are in their prime and hopefully the first frost will hold off for a few more weeks.  The dahlia is the national flower of Mexico and is native to Central America.  The Aztecs called them acoctli “water tubes” because their stems are hollow.  After the first frost, dig the tubers and store in a cool, dry location for planting again next summer.

Fall is a great time to get a head start on planting deciduous trees and shrubs.  The air temperatures are cooling off but the ground is still warm and we’ve had some welcomed moisture. Don’t forget to water your new plantings this fall and winter if there is little rain and snow. Add approximately 4 inches of mulch to retain water and moderate soil temperatures.

Saving your own seed will save you some money and will also help preserve the diversity of plant species.  Save the seed from only non-hybrid varieties, as hybrid varieties will not produce true offspring. Choose strong, healthy specimens and collect seed from as many plants as possible to maintain a wide genetic representation.  For more information see Fact Sheet #7.602 - saving seed.

The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.

Gardening and Insect Fact Sheets are available on-line by clicking HERE.

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This page updated:  September 8, 2003