Questions on: Hosta

Ron Smith, Horticulturist, NDSU Extension Service

Q: I have a hosta plant that has grown too large. Is it possible to divide the plant and replant one of the halves without damaging it? (e-mail reference)

A: Dividing anything causes some damage. However, hosta is a tough customer because it is a member of the lily family. Hosta can be divided using a straightedge shovel. Do it now before new growth commences.

Q: I helped a friend move his hoya plant a few years ago. During the move, a 6-inch segment of the stem broke off. After many months in water, the stem finally grew roots, which I then planted in succulent soil. It has grown many leaves, but has not elongated. At one time, it started to, but then died. Is there anything I can do to get the end of the stem active again? (Mandan, N.D.)

A: Nip it back to some fresh tissue to see if that stimulates growth. I don't know if it will work, but it is the only suggestion I have.

Q: I have a hosta that is looking really great, but I would like to move it. If I dig deep enough around and under the plant/bulb and place it in the same-sized hole, could it be moved without damaging it? It will remain in the same soil and flower bed.
(e-mail reference)

A: You should be able to move it successfully. Do it during the cooler evening hours and water it well after the move. Even if it does wilt, don't worry. In most instances, hosta will recover.

Q: Is it possible to plant hostas under evergreen trees? Is there any type of ground cover that works under evergreens? Thanks for the information. (e-mail reference)

A: Planting hostas under evergreen trees happens all the time. Depending on where you live, so are many other ground covers.

Q: Can hosta plants be planted in a large pot or planter as opposed to the ground? (e-mail reference)

A: Yes!

Q: A couple of years ago we removed a pine tree next to the house. We did not replant for a year. Since then, we have planted hosta and snow on the mountain in this area, but they are very slow growing and seem dwarfed compared with other hosta and snow on the mountain planted nearby. Is the soil too acidic? How can we fix this? (Jamestown, N.D.)

A: Bring in some fresh topsoil and work it into the existing soil. In time, the growth inhibitors in the soil should break down and allow the other plants to grow normally. Acidity easily can be tested by a local garden center or by sending a small sample to the soil-testing lab at NDSU in Waldron Hall. You county Extension Service agent, Tom Olson, should have a soil test bag available for you to use. If the pH comes back at 5 or lower, acidity may be the problem. The addition of any lime product would help correct it.

Q: I have a hosta question. Every year my hosta has increased in size, but this year it is half the size of the year before. The plants are not being eaten by slugs (yet) or any other insect. The leaves look fine. Would there be a reason for this? (e-mail reference)

A: Usually, half the size means that something is wrong in the root system. It is often the start of root rot. If you are game, dig up one of the plants in question and inspect the crown and roots. If it appears healthy, then my next best guess is that the foliage was damaged or removed early last year and not enough carbohydrates were stored to produce the typical foliage.

Q: Is there a hosta that will do well on the west side of my house? It would be planted under a tree, but would get west sun around 4 p.m. until the sun sets. Thanks for your help. (e-mail reference)

A: There is sun-tolerant hosta, but I don’t know which cultivars. A visit to a local nursery may solve the problem for you.

Q: A friend of mine gave me four hosta plants. How far apart should I plant them? What can I do to prevent slugs? (e-mail reference)

A: Plant them 12 to 18 inches apart, depending on what effect you want and how soon you wish it. As to preventing slugs, you can’t. Slugs and hosta go together like potatoes and Colorado potato beetles. All you can hope to do is keep them under control by not overwatering and doing a good cleanup in the fall. If they should get out of hand, there are the usual remedies available at local garden centers.

Q: You make reference to hosta and slugs going together like peanut butter and jelly, but deer love hosta as well. I never have been able to stop the deer from nibbling away at the plants. I’ve tried several sprays and have found one to be a fairly decent repellent. However, this method can be expensive and doesn’t always work. Several years ago, a since-deceased aunt told me someone she worked for put something in her garden to keep the deer away. Apparently, when the wind blows it makes some sort of noise only the deer can hear. Do you have any idea what she could have been talking about? (e-mail reference)

A: Sorry, but I have no idea. Perhaps one of the readers will know and get back to me. If that happens, I’ll pass it on to you.

Q: Something is eating my hostas. Whatever it is, it sometimes starts in the middle and eats holes and other times it starts on the outside edges. I thought maybe it was birds, but I have never seen any near them. Is there anything I can spray to keep away whatever is eating them?
(e-mail reference)

A: Very likely the damage is from slug feeding. Slugs and hostas go together like peanut butter and jelly. There are many ways to control slugs; you just have to choose the method. You can use slug hotels, bait, diatomaceous earth, egg shells and even stale beer.

Q: How do I kill my hostas? I dug them up as deep as I could but everyone keeps telling me that they will come back and I won?t be able to get rid of them. Is this true and what suggestions do you have to prevent this from happening? I would like to know before I plant new shrubs in that spot. (E-mail reference)

A: They are like any other lily, if you leave anything behind, it will sprout and grow. If you did a good job of digging them out, they will be gone. If an occasional loner should show up, it can be dug up or wiped out with Roundup.

Q: Should I clean away all the leaves from my hostas plants this fall? They partially froze so I would like to clean up the beds if it is safe to do that now. (E-mail reference)

A: Go ahead and get them cleaned up or else the slugs will think you have prepared a special winter home for them.

Q: I planted hosta plants on the east side of my house for the first time this year. They did really well, probably doubled in size. I am wondering what to do with them this fall. Is there any special care that they need before or after frost or will new growth just break through next spring? I have the same question about daylilies. (Dickinson, N.D.)

A: After the fall frost nips the foliage back, you can cut it down or leave it there until next spring. It just depends on when you get ambitious. You don’t need to do anything, as far as care, because both species are as tough as crowbars!

Q: What will happen if you fertilize your lawn with crabgrass preventer or Scott's turf builder and don't water it? Will it burn your lawn? When can you transplant an iris? My hosta leaves turned brown from frost in May. Can I cut them back? (E-mail reference)

A: Nothing will happen to your lawn because the material is "prilled" which means it will not activate until it rains or you provide irrigation. Most quality fertilizers have this or similar a treatment for just that reason. You are too late for the crabgrass preventer to be effective this year. Fall is the best time to transplant an iris. Yes, you can cut the hosta leaves back.

Q: I would like to know when to move my yarrow, poker primrose and hosta. Also, my dirt got hard from watering all summer. Can I put new dirt over the old and work it in next to my perennials? Would it hurt to put a small amount of that dirt on top of the perennials using it as a mulch? Would you know why some of my astilbes don't get plumes? I have them on the north side of my house. I would move them if you think they’re not getting enough sun. When would it be best to move them? (Onaka, N.D.)

A: A good rule of thumb is to transplant spring-flowering perennials in the fall and fall- flowering perennials in the spring. Never layer different soil types if at all possible. Improve the tilth by adding organic matter like sphagnum peat moss. The astilbe probably didn't flower because of low light intensity or it was planted too deep. You can move it in the fall but be sure to water in well and mulch all that you transplant this fall.

Q: Can you tell me if the leaves of Engleman ivy, peony or hosta are poisonous? (Cando, N.D.)

A: The Engleman and peony are suspect; the hosta has no references to any poisonings.

Q: We have a variety of hosta plants on the south and east side of our home. The leaves of the plants on the south side are starting to turn brown on the edges. It seems to be limited to the variegated type of hosta, not the solid green hosta. Would heat be the cause or has a disease set in? The east side plants are doing so well and they are of the same variety as the plants on the south side. (N.D.)

A: Yes, variegation will subject the plants to a greater tendency for foliar burn. Mine are doing the same thing. Nothing to worry about, they will likely never die.

Q: My mother would like me to move her perennial flower garden. Could you tell me when is the best time to move hostas and day lilies? (E-mail reference)

A: After a good, hard, killing frost.

Q: We have several hosta plants in 4-inch pots that we have stored inside a shed that is insulated, but not heated. We did not plant these hostas last year because we were not sure where we wanted them. My question is are there any precautions or things that we should do to insure that these plants make it until spring? I realize that it is a little too late to do too much as the winter is almost past. If there is any info you could supply, please do. (Pelican Rapids, Minn., e-mail)

A: Basically keep them moist until they get planted. Try also to keep them dormant until they can get planted. Do this by moving them outside when the snow leaves, but the ground is still frozen. Store them on the north side of your home or garage until you can dig in unfrozen soil. Be sure they are planted where they will get more shade than direct sunlight, and water them in well, initially. Once they start growing, hostas need little care, and certainly no further water. Hostas are a good xeric (low-water-requirement) plant.

Q: This past summer my hostas had some small holes in the leaves. (McHenry, Ill., e-mail)

A: The holes in your plants were likely caused by slugs, and they are probably overwintering right now under the dead foliage--a good reason to be extra thorough during the spring clean-up.

Q. I have four hosta plants on the east side of my house. There is something eating away at the leaves, the holes are everywhere, in the middle, the tips and some new growth has been chewed off also. We do have a pair of ducks that frequent the yard as well as rabbits. Could they be the culprits, and what can I do to prevent this? (Fargo, N.D.,

A. I'm willing to bet that the critters that is chewing away on your hostas are slugs. They are nocturnal feeders and love hostas! There are many baits that can be used to control slugs. Just place them in such a way that the visiting wildlife doesn't mistakenly eat the bait and die.

Also, if you are watering, stop. That encourages the proliferation of these leaf munchers. Hostas are fairly drought tolerant anyway.

Q. Enclosed is a leaf from a hosta plant I have in my planter. Can you tell me what is wrong with it? This is a small hosta, but now I noticed it is also on a larger one. Thank you. (Glenfield, N.D.)

A. I could only see symptoms of a problem, not the problem itself, so here are my best guesses as to what it could be:

1. Crown rot from poor drainage or too much water.

2. Fertilizer burn usually caused when adjacent turfgrass is fertilized.

3. Slug damage below leaf surfaces.

Generally, hostas are pretty tough customers, surviving a barrage of benign neglect and nature s cruel elements. Please refer to the enclosed NDSU Extension publication PP-469, "Plant Disease Management in the Home Garden." Oher readers may get this publication from any county office of the NDSU Extension Service.

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