Planting tips for Hostas


Hostas perform best when planted with ferns and other perennials in prepared beds. They can also be tucked into the landscape on a hole by hole basis if an area of at least 2-3 feet wide is prepared to a depth of 9-12 inches. When planted in the woods with wildflowers it is important to remove all surface tree roots within 2 feet of each hosta clump.

Bed Preparation: The most important ingredient in successful hosta growing is bed preparation. Good hosta soil should remain moist after a good rain yet drain well. It should have enough organic matter to provide plenty of air spaces for vigorous root growth but be firm enough to discourage voles and other rodents. It should have high fertility and a light covering of mulch to keep the soil cool in summer and retain moisture.

Here is how we do it at Green Hill Farm:

First the area to be planted is completely tilled with our old Troy Built tiller to its maximum depth of 8-9 inches. We remove all the surface tree roots that the tiller finds. If the soil is poor and/or hard, we will frequently add 4-5 inches of purchased topsoil, a good sandy loam, and till it in to the existing soil. Then 3 inches (about 30% of the total bed) of organic matter is spread over the bed and tilled in with some 10-10-10 fertilizer to “feed the bark”. We usually use  coarse pine bark nuggets in our beds that are locally available in bulk, but well-rotted sawdust, compost or manure will also work well. The coarser the organic material is the larger the air spaces in the soil will be and the longer they will remain in the soil.

Next, 1-11/2 inches of 3/8 inch gravel, either crushed granite or pea gravel, is spread over the bed and tilled in to a depth of 4 -5 inches, or about half  the total depth of the bed. The gravel gives the bed mass, moderating soil temperatures as well as making it firmer. Also, it is a vole deterrent. If you can dig in your bed easily with your hands then the voles can too. Add some gravel and feel the difference. Finally, after a good rain to settle things a little, the bed is ready to plant.

Hole Preparation: Hostas do not grow deep into the soil, usually no deeper that one shovel depth or so. Wide holes are better than deep holes, since hosta roots usually extend as far or further from the center of the plant as the foliage does. Dig a hole wide enough to accommodate all the roots of the hosta to be planted without cutting or folding them. Make a small mound in the bottom of the hole to rest the crown upon and run the roots down the hill. Loosely fill the hole with soil that has been amended with some slow release fertilizer or manure (especially if planting in the spring). Do not pack the soil around the plant. Water thoroughly and mulch with a thin layer of pine bark, shredded oak bark or what ever is your local favorite. Remember to keep the mulch off the hosta petioles in order to discourage fungal diseases. Also, deep mulches encourage voles.

When to plant:

Hostas can be successfully planted any time that the ground can be worked. The best times to plant hostas are when they are actively making new roots, in the spring after the first flush of leaves has hardened off and in late summer once the hottest weather is past. Here in North Carolina that is usually early May and late August. Most plants that we ship to retail customers are sent during those optimum times. Planting at these times allows the plants enough time to establish a good root system before the droughts of summer in the first case and before they go dormant for the winter in the latter.

Containerized hostas can be planted with a minimum of shock throughout the spring, summer and into fall. They should be completely bare rooted before planting and their roots untangled. If your hostas arrive bare root they will probably appreciate being soaked in a bucket of water for several hours to rehydrate them before planting. Pinching a leaf or two will also reduce desiccation shock and usually stimulate another flush of leaves. Hostas usually acclimate completely to their new homes in 1-2 weeks and should be kept moist during that period. A topdressing of fertilizer will also encourage rapid new growth.

Over time

Finally, for hostas to achieve their maximum potential, the soil must be able to readily take up the water and nutrients that they need. Good bed preparation in the beginning makes all the difference. This however is not the end of the process. Over time tree roots will reinvade your beds robbing your hostas of water and heavy rains will compact the soil making it hard for any water to penetrate deep into the bed. Alas, then the beds will need reworking. Remember, a garden is never completed, it is always a work in process.

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How late is too late to plant hostas in the fall?

August is a great time to plant hostas almost anywhere in the country. You can safely plant them all month in the Midwest and North and the latter half of the month in the South. My standard rule is you want to get them in the ground 4-6 weeks before the first frost. This allows them to make some new roots while the soil is still warm and then have some time to prepare for winter.

Most of us, though, have planted hostas in the ground later than that with good success. I have planted them as late as the first week of November without any noticeable ill effects. You do run a risk with late planting however. Hostas are completely dormant during the winter, and they will not produce new roots until after they have made new foliage in the spring. They literally sleep through the winter.

Late planted hostas may rot over the winter if 1) the ground is frozen and stays frozen shortly after they are planted, 2) they are very dry when the ground freezes, 3) the soil stays too wet because of poor winter drainage or 4) heaving occurs during cycles of the soil freezing and thawing. Snow cover or a covering of mulch will help with all these situations. Remember, blue hostas, as well as many gold hostas, with H. sieboldiana and H. ‘Tokudama’ parents as well as some H. longipes types are the most susceptible to winter kill. Miniature hostas may also completely heave out of the ground, resulting in cold damage to the crown.

So, with late hosta planting, first make sure the plants are full of water when the first hard frost hits. Then try a little mulch to protect the hosta crowns and moderate soil temperatures. (Beware! Deep mulches may entice mice and voles to make their winter homes in your hosta garden.) With a little luck from the winter weather you can probably extend your planting season another month or so, even after the first frost.

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Running out of space? Try small hostas

Unfortunately, none of us have unlimited space to plant hostas. Even the largest gardens finally begin to fill up. Frequently, however, our ability to maintain the garden limits our need for new hostas long before the space runs out. Small hostas solve both these gardening dilemmas.

Obviously, planting hostas whose ultimate size is two feet wide or smaller reduces the amount of lawn that must be converted to hosta beds each spring. Looking at it another way, selecting small hostas allows you to buy that extra plant or two without worrying where you are going to plant them. You can always find room to tuck another little one in somewhere. Large hostas require more planning.

Large hostas also require more maintenance. Aside from the additional initial bed preparation time and effort, large hostas are just hard to handle. If grown in containers they seem to always be sending new roots out those little holes in the bottom of the pot. Small hostas need not be repotted as often. And thoughts of procrastination begin to creep into our minds when those old giant clumps need dividing. That is, unless there are three strong, young boys down the street or your neighbor has an electric wench on the front of his 4 X 4.

Small hostas are easy to divide. Many do not even require a knife, they just pull apart with your hands and they do not need a crane to lift them out of the hole. Also, frequently they increase faster than large hostas so there are more surplus divisions to pass on to other hosta friends. Dividing small hostas every two or three years also keeps them small. And it keeps them cute.

In the garden I like to see small hostas grouped in areas by themselves, away from their bigger brothers and sisters. Frequently these beds are raised, bringing these smaller plants closer to eye level. I have seen several of these “mini beds” mulched with gravel or small river rocks. The effect is both clean and eye-catching.

We used to see small hostas regularly used as border plants. Long rows of ‘Golden Tiara’, ‘Gold Edger’, and ‘Kabitan’ still fill my mind’s eye. As collectors, many hosta growers cannot afford to allot so much space to any one cultivar, But for landscape effect, a border of almost any small hosta will define space as well as carry the eye around the garden.

We have listed several small hostas this fall for you to try. We will be glad to answer any questions you may have about their growth habits. Remember, small hostas make great container plants too.

Preparing the Garden for Winter

With the all the cool wet weather we’ve had this summer, (if it was so hot and dry in the plains it had to be cool and wet somewhere), I fear we will have an early winter. As the hostas in the garden are already looking forward to their long winter’s nap, my mind drifts off to winter cleanup. Here’s a checklist:

1. Label, label, label. Don’t wait until those plastic tags have faded or been scattered by the leaf blower, re-label all your new hostas now. I like to bury a plastic label with the hosta name written in pencil at the same position for each hosta clump in the bed, say 3 o’clock as you view it from the path. They will last for years underground.

2. Make one last check for pest problems, especially voles and foliar nematodes. In the latter case, remove badly damaged plants from the garden.

3. Leaf removal, both tree and hosta. If it is not an overwhelming task, try to remove the dry hosta foliage from the garden, (do not compost), after a couple of nights of hard freezing weather. This will help decrease next year such pest problems as slugs, fungal infections, and foliar nematodes. Also, cutting scapes will prevent unwanted hosta “weed” seedlings from appearing in the spring. Piling the fallen tree leaves will provide a good winter mulch for the garden but will also make excellent winter housing for voles. It is probably best to remove those leaves from the beds by gently raking or blowing with a leaf blower. Then a thin layer of mulch, (pine bark is my favorite), can be applied to prevent heaving and protect the hosta crowns.

4. Stop watering the garden. Sounds silly but hostas would rather be dry in the winter than wet. Also the lack of water will encourage newly planted hostas to go dormant and not keep throwing up new leaves.

5. Plant early spring bulbs for early color in the garden. Crocus and tulip foliage will be out of the way by the time the hostas start to spread.

6. Finally, or maybe this should have come first, plant all the hostas you bought this summer in the ground. Hostas overwinter much better in the ground than they do in pots and if they are not in quite the right spot when they come up next spring, they can be easily moved. This also removes any lingering guilt that you may have next spring when it comes time to by more hostas.

Hopefully, it will be a long warm autumn so that we can get all our gardening chores finished before the snow flies.

Copyright (c) Green Hill Farm Inc. 2003, 2006
December 3, 2006