Hostas and Sunlight
Growing hosta and in the best sun conditions is worth researching and testing! Hostas are “shade tolerant” but some varieties are also more “sun tolerant” than others. Like any plant, hostas need some sun to survive and thrive. Our HostaSearch™ Database offers suggestions for light tolerance on many hostas. To learn about hosta colors and the sun’s influence on hosta colors, visit our Hosta Colors page and see our sun tolerant hostas for sale.
Hostas will grow in most light conditions, given enough water, but they may not thrive, have good color or the color you desire, or have their best foliage in every light and heat condition. Depending upon the genetics of the plant, the same plant can have often three or more different leaf colors, and they can change during the growing season, depending upon various factors. And, don’t forget the colors of the surrounding plants can also enhance certain leaf colors.
The two clear signs your hostas are growing in too much sun or not getting enough water are:
- Browning at the tips of outside edges of the leaves
- Dull color or faded spots in the leaves.
(Note that leaf color variation depends on location, as well as amount of sunlight – for that reason, it’s normal to see color change throughout the growing season.)
Best Location for Hostas
Learn how to determine the best location for a hosta variety, and how to achieve the particular leaf color you desire.
What are the plant genetics or characteristics of the plant?
All hosta varieties originated from about 40 species in Japan, China, and the islands of South Korea – these originals created the gene pool for the remaining 8,000+ cultivars. From determining the origin specie plant, it becomes easier to learn in what locations a certain cultivar will best thrive. As a general rule, these characteristics denote more sun-tolerance: Thick leaves, flower fragrance, or yellow leaves, white leaves, or some combination thereof.
What type of light will the hosta be grown in?
Deciding which sort of sunlight your hosta will receive is a task in itself. Do you choose morning sun? Afternoon? Evening? What about dappled, filtered, or full sunlight? Remember that full sun in the morning and evening sun is cooler (and less intense) than afternoon sun. Dappled and filtered light, if it’s all day, is usually better than full sun. It’s also possible to create extra shade with tall ornamental grasses, trees, shrubs, abors, pergolas, trellises, shade clothes, and climbing vines. Remember, you can always move your hostas to different locations if necessary – transplanting is easy!
How will the light change during the course of the growing season?
Some growing areas may be shadier or sunnier during different times of the year due to the angle of the sun in relation to your trees, roof line, etc. Learn more about your sun and shade conditions here.
What is my growing zone?
Southern gardens get more direct, intense sun over a longer period of time. Certain varieties of the hosta family perform better in southern locations than others. As an example, the species Hosta plantaginea is the only fragrant hosta of the original 40 or so “species” hostas. It is native to southern parts of China and is far south in the overall range of species hostas. Most of its offspring can be grown in full sun and are more heat tolerant. They can be grown in zones 3 to the northern parts of zone 9A.
How much water will my hostas receive at different times of the year?
Hostas prefer at least 1″ of moisture per week. Though they are fairly drought-tolerant, it is possible for hostas to go into heat dormancy. Heat dormany occurs when temperatures are too hot, or when plants aren’t receiving sufficient moisture. When hostas enter into heat dormancy, they discontinue growing, choosing instead to conserve their energy. However, in many cases, cool fall temperatures and moisture brings them out of dormancy.
They higher the altitude the more intense the sun will be. Plan accordingly and test.
General sun/leaf color rules:
- Darker colored hostas need less sunlight to thrive. This is because they have more chloroplasts in their leaves, and photosynthesis can occur with less light.
- Lighter green or yellow hostas often require more sunlight.
- Medio-variegated (white centered) hostas tend to burn in too much sun unless the hosta has thicker leaves (often found in tetraploid hostas – most hostas are diploids). When placed in full sun, chlorophyll levels can increase in medio-variegated hostas, causing the leaves to pick up a green cast, and look less variegated. Morning or late afternoon sun is recommended for white variegated hostas with thinner leaves.
- Yellow or yellow centered hostas need at least two hours of direct sun to look their best. Without enough sun, yellow hostas may stay green instead of turning yellow; yellow margins may not lighten to cream white. They generally are the most sun tolerant hostas.
Hostas with green, chartreuse, or yellow leaves are able to handle more sun (providing the roots receive adequate moisture). Depending on the variety, hostas can grow in full sun, but they’ll need plenty of water to survive. Full sun can also cause hostas to burn and brown later in the growing season. If you grow hostas in afternoon sun, make sure they’re being watered more often than shade-grown hostas. Hostas that can tolerate more sun are noted in our HostaSearch™ Database.
There are several benefits to growing hostas in full sun, such as bigger root systems, faster growth, and more leaves. However, the leaves will also be longer and more narrow, and colors can appear bleached or washed out. (See the color difference in two ‘May’ hostas grown in different light conditions.) Occasionally, hosta leaves can bleach and lose color without burning.
Hosta ‘May’ grown in different amounts of sunlight.
H. ‘May’ with more sun
H. ‘May’ with more shade
Here is a video by Tom Carlson showing an example of leaf bleaching.
Effect of Sun/Shade on Size
Owner Tom Carlson shows the stunted growth of a Hosta ‘Mr. Big‘ planted side-by-side due to lack of sun.
Shade varies in intensity. Light cast by a high tree canopy is only partial shade and ideal for hostas. Hostas with blue-green leaves and white variegation, whether in the center or margins, do best in shaded areas.
Soil and Slopes
Will my soil retain moisture or will it drain fast? Obviously, fast draining, sandy soil requires more moisture. Take time to amend your soil. Slopes may not allow adequate moisture to penetrate your soil. Hosta roots can grow down to 18″ deep. Make sure the water seeps all the way down to the bottom roots, keeping in mind that water may run off the hosta’s foliage or evaporate in overhead trees branches, etc. Applying mulch can help with moisture retention. Learn about planting hostas and soil preparation.
Do you want blossoms?
Hostas need some sun to produce outstanding blossoms and some hostas more sun than others. In particular, hosta plantaginia and offspring of plantaginea need more sun to develop their blooms. Hosta plantaginea ‘Aphrodite’ needs possibly the most sun of all hostas, but their HUGE and beautiful blooms are worth the effort. Fragrant hostas need 4 to 6 hours of sun to develop their fragrance.
What type of wind and sun will my plants receive?
Hostas with larger leaves can lose moisture from their leaves faster in sunny or windy conditions through a process called transpiration (a bit like perspiration in people). Pores in the hostas leaves, called stomata, open up and allow water to escape – wind and sun will accelerate moisture loss. Consider planting larger leaved hostas in shadier, wind-protected locations.
What is the pH of the soil that my hostas will be grown in?
Hostas prefer an acidic soil with a pH of 5.7 to 6.8. Basic soils with a pH of 7.2 or more may cause leaves to be more yellow – this is because the plants are no longer able to absorb certain nutrients. Leaf-yellowing due to incorrect pH levels is called chlorosis.
Gray and blue hostas
Hostas are gray or blue because the specific cultivar (type of hosta) has a gene that creates extra crystalline wax on the top and/or bottom side of the leaf. Direct sun can cause this wax to melt off, which causes the hosta to show its underlying green color. Some varieties have more intense blue color and some hold their blue or gray color longer into the season. The wax might also rub off due to high winds or water dripping off a roof.
For more information on blue hostas, please visit our Blue Hostas Information Page.
To purchase blue hostas, please visit our Buy Hostas Page, where you can filter and search by blue leaf color.
Gold or yellow hostas
Generally, gold hostas will tolerate more intense sunlight better than other hostas. Most yellow hostas also require more sun to bring out their full color potential.
For more information on yellow hostas, please visit our Yellow Hostas Information Page.
To purchase yellow hostas, please visit our Buy Hostas Page, where you can filter and search by yellow leaf color.