By: Mary H. Dyer, Credentialed Garden Writer
You’re in luck if you’re a northern gardener looking for cold hardy hostas, as hostas are remarkably tough and resilient. Exactly how cold hardy are hostas? These shade-tolerant plants are suitable for growing in zone 4, and many do just fine a little further north in zone 3. In fact, hostas require a period of dormancy in winter and most don’t take a shine to warm southern climates.
Zone 4 Hostas
When it comes to selecting hosta varieties for northern gardens, nearly any hosta is perfect. However, it appears that light-colored hostas are more susceptible to damage by frost. Here is a list of some of the most popular hosta plants for zone 4.
Giant Hostas (20 to 48 inches (50-122 cm.) tall)
- ‘Big Mama’ (Blue)
- ‘Titanic’ (Chartreuse-green with golden borders)
- ‘Komodo Dragon’ (Dark green)
- ‘Humpback Whale’ (Blue-green)
Large Hostas (3 to 5 feet (1-1.5 m.) wide)
- ‘Elvis Lives’ (Blue fading to blue-green)
- ‘Hollywood Lights’ (Dark green with yellow centers)
- ‘Parasol’ (Blue-green with creamy yellow borders)
- ‘Sugar and Spice’ (Green with creamy borders)
Mid-Size Hostas (1 to 3 feet (30-90 cm.) wide)
- ‘Abiqua Drinking Gourd’ (Powdery blue-green)
- ‘Cathedral Window’ (Gold with dark green borders)
- ‘Dancing Queen’ (Gold)
- ‘Lakeside Shore Master’ (Chartreuse with blue borders)
Small/Dwarf Hostas (4 to 9 inches (10-22 cm.) tall)
- ‘Blue Mouse Ears’ (Blue)
- ‘Church Mouse’ (Green)
- ‘Pocketful of Sunshine’ (Golden with dark green borders)
- ‘Banana Puddin’ (Buttery yellow)
Tips on Growing Cold Hardy Hostas
Be careful of planting hostas in places where the soil may warm up earlier in late winter, such as south-facing slopes or areas that get a lot of bright sunlight. Such areas can encourage growth that may be nipped by an early spring freeze.
Mulch is always a good idea, but should be kept to no more than 3 inches (7.5 cm.) once the weather warms in spring, especially if your garden is home to slugs or snails. By the way, hostas with thick, textured or corrugated leaves tend to be more slug-resistant.
If your hosta is nipped by an unexpected frost, keep in mind that the damage is rarely life-threatening.
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Hostas fit the bill in both situations: they adapt well to both part and full shade. Following is a list of some good companion plants for hosta, along with their USDA Hardiness Zones. (Hardiness may vary among varieties.) This is just a small selection, so don't limit yourself to these few!
- astillbe, zones 4 to 8
- baptisia, zones 3 or 4 to 8
- bellflower, zones 4 or 5 to 9
- bleeding heart, hardiness varies
- dianthus, zones 4 to 8
- geranium, zones 4 or 5 to 8
- heuchera, zones 4 to 9
- lysimachia, zones 4 to 8
- pulmonaria (lungwort), zones 4 to 9
- tiarella, zones 4 to 9
- tradescantia, zones 4 to 9
Hostas have become almost synonymous with shade gardens, and with good reason: hostas are hardy, vigorous, and reliable. Although they produce attractive spikes of purple or white flowers in midsummer, hostas are grown primarily for their attractive foliage, and plant breeders have created varieties in a remarkable range of sizes and colors.
Experienced gardeners know the value of foliage plants. Many types of perennial flowers are at peak bloom for just a few weeks. Plants with attractive foliage such as hosta fill in the gaps and help create season-long interest. This is especially true in shade gardens, since many shade-loving plants have more subtle blooms or have a shorter bloom time than many familiar sun-loving plants.
Understanding Light Levels
Full sun is commonly defined as direct sunlight for at least 6 hours during the middle part of the day. If your garden gets direct sunshine from sunrise until noon, or from 3 p.m. on, even if that equals six hours in mid-summer, consider the site part shade. Morning and evening sunlight isn't as strong as mid-day sunlight. The same goes for sites that receive filtered or dappled sunlight all day. For areas that fit these descriptions, choose plants designate for part shade.
If your garden is located on the north side of your house or shaded by a dense tree canopy, you'll need to choose plants adapted to full shade.
There are several plants that make excellent groundcovers, including lady's mantle, lamium, lily-of-the-valley, pachysandra, and vinca. Since it can be challenging to establish a lawn in shady areas, consider replacing lawn grasses with shade-tolerant ground covers under trees or on the north side of your house -- wherever it's shady. Hostas may be planted among the ground cover plants, or can be used on their own to cover large expanses. Look for dwarf varieties for a low-growing ground cover -- some varieties grow to a height of just 8 inches.
There is no better way to brighten up a shady spot than by planting hostas. Although the plants bear tall spikes of white or lavender flowers in midsummer, hosta are planted primarily for the season-long show of their striking foliage. It takes more than good looks, however, to make a plant a world-class winner. Few perennials are truly carefree, but hostas come close. They never need dividing. Once established, they shade the ground so thoroughly that they reliably crowd out most weeds. Hostas are not fussy about soils, and many cultivars even do quite well with considerable sun. It's no wonder gardeners are planting them in record numbers.
Hosta leaves come in a broad range of solid colors, from blue-gray to deep green to light green or gold. Blue hostas often have a soft, waxy bloom (a powdery-looking coating on the leaves, also found on grapes), especially early in the season. Some green varieties have very shiny leaves others have a matte appearance. Variegation can be white, cream, or yellow and can occur on the edges of the leaves, in the centers, or streaked throughout the leaf. The most common leaf shape is heartlike, but some cultivars have narrow, straplike leaves. The largest hostas are 3-4 feet tall the smallest are under 8 inches. Mix all these factors together and you get an idea of why plant breeders are having such fun with this group of plants.
Hostas are among the most adaptable perennials. They do well from USDA Hardiness Zone 3 (-40°F minimum) southward as far as zone 9 (20°F minimum). Hostas need a period of cold weather, at the onset of which they turn a pleasing yellow and then go dormant. Insufficient winter chill and dry air, such as in western deserts, are the chief limiting factors.
Some hostas are native to woodlands and others grow in moist meadows where tall grasses provide some shade. In the garden, one-third shade is ideal. If soil moisture is ample, most hostas can take direct sun, especially in cooler climates and at the northern limit of their range. Gold varieties must have some direct sun for their full color to develop in shade they become chartreuse. Blue varieties develop best color in shade. When hostas get too much sun or not enough water, the leaf edges become papery and brown. At the southern edge of their range, more shade is beneficial.
Typically, the plant you buy is a one- or two-eye division. The eye is a piece of a stubby underground stem, called a rhizome, containing a single squat, conical bud from which the leaves arise. The many roots that grow from the rhizome are about as thick as heavy twine, something like the roots of daylilies.
New rhizomes form slowly, and a clump may take a few seasons to fill out. However, don't be tempted to crowd the plants follow spacing recommendations carefully. You can fill in between the plants with daffodils, Virginia bluebells, or annuals.
A little extra TLC will get new hosta plantings off to a strong start. Be sure to water the plants during dry spells, especially during their first growing season. Apply a 2-inch-thick mulch of compost or leaf mold each year to provide nutrients. Hostas growing in the shade of large trees may need supplemental waterings to help them compete with the tree roots.
The only major pests of hostas are slugs, which thrive in the moist, cool, shady areas that hostas love. Controls include handpicking, traps, and deterrents like a layer of diatomaceous earth or crushed eggshells spread underneath the plants.
Unlike many perennials, hostas do not need regular dividing to keep them growing strong. Established hosta plantings have been in place for 30 years and longer with no need for dividing.
Empress Wu Hosta (40″T x 70″W) and Gentle Giant Hosta (46″ T x 70″W) have been two of our biggest sellers of the giant hosta varieties that we grow over the last two growing seasons.
Hosta gardeners are clearly obsessed with size and I can understand this from my own gardening experience. A four foot tall Gentle Giant sitting out in, or standing out in, a hosta bed is a tantalizing thought.
Sum and Substance Hosta (32″T x 72″W) and Blue Angel Hosta (32″T x 70″W) were the big two in popularity among the hosta giants for a long time. And they still are popular. No hosta garden should be without them.
The Hosta Victory (35″T x 70″W) and Dream Weaver Hosta (30″T x 72″W) are also very popular and have the added feature of being variegated.
The giant hosta Dream Weaver is a personal favorite due to the contrast of the blue-green border and the creamy-white center.
How large a hosta can reach in size is not only determined by the cultivar you choose.
Location has a great deal to do with its ultimate size. Giant hosta plants need unlimited water and a deep rich soil, more so than the smaller cultivars of hosta.
Basic Hosta Plant Care
Once your hostas are planted, maintenance is the easy part. Water hostas frequently—they thrive on moisture and humid climates. Too much sun dries out hostas and interrupts their growth. Although hostas are typically not disease-prone, slugs are a difficulty you may face. There are a number of different "slug traps" to rid your garden of these pests, one of which includes beer (you heard us right—beer!). Fill a shallow dish with beer and place next to your hostas. Slugs are attracted to yeast, so they'll steer away from your hostas and toward the beer trap. Also try spreading eggshells or coffee grounds around your hosta plant—both of these are fatal barriers to slugs.
How to care for hostas
Consistent, even moisture equivalent to 1 inch of water per week is considered best for hostas.
Deeper infrequent watering is better than frequent shallow applications.
Hostas planted in dry shade, in sunny locations, or beneath shallow-rooted trees, such as maples or spruce, may need additional water.
Organic mulches, such as shredded bark, shredded leaves, or pine needles, will help to conserve the moisture needed for hostas.
Apply mulch after the soil warms in late spring to early summer to maintain a 2- to 4-inch layer, taking care to keep it away from the plant’s central crown.
If a soil test indicates fertilizer is needed, apply it twice during the season for optimum growth.
Apply first in spring as leaves emerge from the ground
Apply once more before flowering
Discontinue fertilizing after the end of July as it could interfere with the plant’s ability to prepare for winter
Deadheading, or removing flowers, can be done at different stages.
Trim off hosta flowers before they mature so not to distract from the leaves.
Or wait until the blooms have died then cut the stalk off down to the crown of the plant.
Flowers should not be allowed to set seed because this can defer energy at the expense of leaf or root development.
Pruning is unnecessary during the growing season other than trimming off yellowed or hail-damaged leaves or dead flowers for a tidier appearance.
Rake up and compost or dispose of dead leaves in late fall to reduce build up of disease and insect pests. If diseases have been an issue, discard infected leaves.
Winter protection is generally not necessary for hostas. Provide some extra mulch for winter protection, especially for plants transplanted late in the season.
Wait until the ground has frozen to about 3 inches to apply mulch.
Remove excess mulch in the spring as weather warms making sure it is away from the crown of the plants to avoid crown rot.
We're Quite Choosy About What Hostas And Companion Plants We Grow
At New Hampshire Hostas, we take our time reviewing and choosing what new hostas and companion plants we're going to grow in our greenhouses for next year's growing season. You should hear the comments going back and forth! (Actually, it's better that you don't - written with a smile!)
We're passionate about what we grow here and what we feel our enthusiastic hosta customers would like in their gardens. So, after careful thought and lots of expressions, we're pleased to present our choices for 2021. If there is a specific hosta cultivar you are looking for and would like us to sell, please e-mail us or suggest it to us on Facebook!
Giant Hostas - New for 2021
Large Hostas - New for 2021
Medium Hostas - New for 2021
Small Hostas - New for 2021
Miniature Hostas - New for 2021
Companion Plants - New for 2021