Hosta Growing Tips

Hosta Growing Tips
White Oak Nursery

Blue Hostas

The blue color in hostas is generated by light reflecting off a waxy substance covering a green leaf. As the season progresses and that waxy coating is degraded by exposure to sun and rain, hostas tend to lose their "blueness." Thus, blue hostas grown in sheltered environments (i.e., less sun exposure) will tend to retain their blue color longer than those exposed to harsher conditions.

Dividing Hosta Clumps

At the nursery we divide clumps every two or three years to increase our stock. We perform this function in the spring shortly after the "bullet" stage...when the divisions have just begun emerging from the ground. Try to salvage as much of the root system as practical. After the clump is dug, we wash the roots so that we can see where to divide....otherwise you may cut too many roots. We use sharp kitchen knives to perform the actual division...using a size that fits the size of the hosta. Most hostas have a basal plate of hard tissue between the foliage and the roots. Try to cut through only this basal plate area...and avoid cutting off roots. We generally transplant immediately after division, although sometimes we'll allow the plant to "harden off" for a day or so. The hardening off process may reduce chances of rot....but we rarely have this problem even when transplanting immediately.

Fertilizing Hostas

In general, it is best to wait until a newly planted specimen has put out new roots before applying fertilzer. An exception is timed release fertilizer which may be applied to new plantings. For our established hostas we feed with a balanced granular fertilizer (13-13-13) in the spring before the leaves have fully emerged. After the leaves have emerged we recommend using a balanced water soluable fertilizer. If you use granular fertilzer after the leaves have emerged, try to ensure that none of the granules stick in the foliage....most fertilzers will burn the leaves. Generally, a good overhead watering will wash the fertilizer off the leaves. If you have access to well rotted animal waste compost you may add this to your beds....but keep the compost from hilling up on the plant's growing tips as this promotes rot.

Hosta Pests

The four main pests most hosta gardens face are deer, rabbits, voles and slugs/snails.
We've tried most of the common deer deterrant methods...and none of them work....although one of our customers maintains a product called Plant Skydd works well for her. We're convinced that only fencing is effective and that solution is rarely practical. Luckily deer are browsers and generally just take a nip here and a bite there. However, they will occassionally shear a clump. Deer have a definite preference for fragrant hostas...we suspect they're "sweeter." Dogs can also be effective guardians of the hosta patch.
Rabbits can be captured or killed in traps. Generally the only time we have trouble with rabbits is early in the spring when the leaves are just emerging. Once the plants mature we rarely see rabbit damage. Again, the common methods of deterrant (human hair, blood, soap, fox urine, etc.) have not been effective for us.
Voles (and perhaps field mice) are our biggest pest problem. They burrow under the roots and eat not only the fibrous roots but the basal plate as well. Generally, this damage is performed in the winter when the plants are dormant. Most of the plants damaged in this way will live but will be much reduced in size. If you suspect voles, dig the plant and examine the roots. The lack of roots will be obvious and the rodent's teeth marks on the basal plate are frequently visible. Luckily, voles are fairly easily controlled by putting poison seed (which can be obtained in most garden centers) in their holes/burrows. Snakes are also fond of small rodents.
Slugs (and in some parts of the country, snails) eat holes in the hosta leaves and are the most commonly described pest affecting most gardeners. They are also easily controlled by the regular application (about every three weeks) of slug bait which may be obtained at most garden centers. We have not used slug bait at the nursery for about ten years now. We have a small pond which produces lots of toads and frogs and these helpful creatures, in addtion to our wild turkeys, keep the beds slug free. Slugs may be controlled by hand picking as well. A few small flat boards placed strategicallly throughout the garden, but with a little space under each, will attract the slugs since they like to hide. Just look under the boards every couple of days and remove and destroy the slugs. If you're more adventurous you may stalk the garden at night with a flash light and catch the slugs on your hosta plants (generally on the underside of leaves). Some people swear that putting small bowls filled with beer in the garden (buried so that the rim is not an obstacle to the slug) attracts these noxious creatures. They then drown in the bowl. We know this method to be effective....but very messy.
It must be kept in mind that regardless of all the above discussion about pests, hostas are just about the hardiest and most trouble-free plant you can have in your garden.

Potted Hostas

We use a number of potted hostas in our home gardens. Each spring we fill the pots with compost and then plant the selected speciman....usually a clump. If compost is not available you'll want to make sure the planting medium has some form of time release fertilizer included or added, since watering frequently (which is usually required for potted plants) leaches nutrients. Clay pots require more frequent watering than plastic pots. In the fall we remove clumps from the large pots (5 or 10 gallon pots) and replant the hostas at the nursery. For hostas planted in smaller pots, we sometimes bury the entire pot in the ground....ensuring the soil level in the pot matches the surrounding soil level. Thus, the plant is ready to go the following spring without experiencing transplant shock. Some of our Southern customers have told me they refrigerate potted hostas in December to fool the plant into dormancy and then take the plant out in February at which time the plant will emerge from its dormant state.

Refrigerating Hostas

If your hosta order arrives at a time that makes it difficult or inconvenient for you to plant them quickly we recommend you refrigerate them. First, unwrap the plants to determine if the roots are still moist. If they are, rewrap them and refrigerate as is. If the roots are dry soak them for a few hours in tepid water, then re-wrap them....being careful to make sure they are just damp and not soggy. Be very careful to ensure there is no moisture on the leaves. The length of time you may successfully refrigerate hostas is directly related to how far the leaves have emerged. If the hosta are in the "bullet" stage...just starting to emerge from the ground...they may be stored for several weeks. If the foliage is more mature you'll have to plant them after a few days.

Shade/Light For Hostas

All hostas grow better with some shade. The ideal shade condition is high, dappled shade. Conversely, hostas will NOT do well in continuous dark shade....such as that provided by low growing evergreens. Green and gold hostas will generally take more sun than blues. The same hosta will look different when grown in sunny versus shady conditions. In general, the more sun a plant is exposed to, the lighter the colors will be.

Soil For Hostas

Hostas will tolerate a fairly wide range of soils. However, they prefer good tilth conditions and a neutral to slightly acid pH. We amend our yellow clay with course sand and LOTS of compost. Since compost tends to disappear we try to add more every couple of years or so.

Spacing Hostas

Of course, the smaller varieties need to be planted closer together than the larger varieties. In general, we find that planting the Large types about 30-36 inches apart will result in a "filled-in" look in a couple of years. Planting Medium varieties about 18-24 inches, Smalls about 12-18 inches and Dwarfs 6-8 inches apart will achieve the same result in most cases. Please keep in mind that some varieties reproduce faster than others and some spread faster than others too. These suggested spacings will achieve a "ground cover" look....but if you're trying to create a "specimen" garden you'll probably want to increase these spacings so that the individual plants can be appreciated without the distraction of being cheek to jowl with their neighbors.

Streaked Hostas

Streaked hostas are generally unstable. This means that the plant will eventually change into a different form if left undisturbed. Usually such plants will change into a light color edged variety, a light center type or will develop solid color leaves. Examples of such hostas are: 'Dorothy Benedict,' 'Sweet Standard,' 'Fascination,' 'Galaxy,' and 'William Lachman.' In some cases the new form has been registered as a separate variety. For example, the cream edged form of 'Dorothy Benedict' is 'Nifty Fifty' and the all blue form is 'Janet's Joy.' Streaked hostas may generally be preserved in this form by periodically digging the plant and removing any divisions that do not conform to the desired streaked look. However, such plants will never achieve the huge size of varieties that are left undisturbed for many years.

Transplanting Hostas

We have many clumps in our home gardens that have been undisturbed since 1989. However, if a hosta is not doing well in one location it sometimes helps to move it. In any event, hostas are best transplanted in the spring. We prefer to move them in the "bullet" stage....i.e., when the divisions are about an inch or two above ground and the leaves are still tightly wrapped. They should be replanted at the same depth they were growing in the old location. Obviously, you should try to preserve as much of the root system as you can. If you don't plan on dividing the clump, try to keep the root ball intact as you move it.

Watering Hostas

When exposed to high heat and direct sunlight mature hostas will need at least an inch of water per week. However, in more normal conditions established clumps can generally go for several weeks without water. Obviously, dwarf and small hostas with their shallower roots will need more frequent water than larger varieties. In addition, newly planted hostas, regardless of size, need fairly frequent watering until their root systems become established. Hostas will tolerate some standing water but if that condition lasts for more than a couple of days rot may develop.

Winter Care For Hostas

Hostas need a period of dormancy, brought on by colder weather (and perhaps decreased light). Click here for a plant hardiness zone weather map. We prefer to leave the foliage undisturbed until late in the winter (i.e., late February/early March). At that time, while the ground is still frozen, we rake off all of last season's decayed leaves, etc. In climates involving a frequent freeze/thaw cycle (like Illinois) hostas may heave. For the medium and larger varieties this usually is not a big problem. But dwarf and small hosta may die when their root systems become exposed. Thus, we recommend covering the smallest hosta with a couple of inches of compost (or peat moss) so that if they heave they'll find themselves in a friendlier environment. Then in mid or late March before the leaves start to emerge, we gently rake off the compost.

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