14 Common Problems With Hosta Plants
Curious what kind of problems hostas can carry with them once they are planted? Hostas can run into several issues, but many of them are preventable or treatable. In this article, certified master gardener Laura Elsner walks through the most common problems with hosta plants and how to prevent or fix them.
Hostas are a favorite shade perennial in many gardens around the world. They can anchor a garden with their large mounds of foliage in various shades of green. They don’t spread or wander. Hostas are low maintenance. There are so many different varieties that you can plant a variety of hosta in almost any space.
But of course, like every living thing, hostas aren’t without their problems. From leaf curl, to yellowing and browning leaves, these plants aren’t immune to a number of different issues. However, with a little planning and forethought, you can prevent or eliminate most of them.
If you are having issues with your hostas, this comprehensive list of common hosta problems can help you identify and resolve any issues you may have. With a little bit of care, you’ll have your hostas back to green & pristine condition in no time. Ready to learn more? Let’s dig in!
Yellowing leaves in a hosta can be caused by a variety of things. But the first thing to check is the soil. Wet heavy clay soil that cannot properly drain could be the problem. Hostas like light free draining soil best.
Do a quick test on your soil by grabbing a handful of it. Squeeze it together in your hands and release it. It should just crumble away in your hand. If it stays in the shape of the ball like putty, it is too heavy. Use coconut coir or peat to break up the heavy soil. You can work it in around the base of the hostas.
If you checked the soil and it doesn’t seem too heavy, perhaps it is a watering problem. Do not over water your hostas. Especially if they are in more shade. This will cause the leaves to turn yellow and eventually could lead to stem and crown rot. Another sign could be petiole rot, which I will address below (#10).
Brown and Crispy Leaves
Crispy leaves on hostas could be caused by a few different things. I would first check the watering. If hostas are not getting enough water they can get brown and crispy.
The other thing that could be happening, is too much sun. I say to check the watering first because hostas can take more sun if they are getting more water.
Make sure to water longer and slower rather than a quick spray. I like to use a drip hose snaked through the garden that I turn on for a couple of hours at a time a few times a week (depending on rain and heat).
Stick your finger into the soil to check the soil. Even if it appears wet on top, it might be dry right underneath. Trim off the crispy leaves and make sure to be watering regularly.
Bleached leaves on a hosta is a sign they are in too much sun. If you first plant a hosta in a spot and they get bleached leaves, trim them off and give them lots of water. It may take them a while to adjust to their new garden conditions.
If it is a continuous problem, start my watering more often. If this doesn’t help it is time to consider moving the hosta to a shader location. It is best to move a hosta in early spring, or late fall. But if it is bleaching and crisping quickly, I would move it asap.
Preferably a cloudy cool day but if that isn’t an option opt for morning or evening. Dig up as much as you can without disturbing the roots (this is actually fairly easy to do with hostas, they have shallow roots). Transplant to a more shaded location and water well.
Another option could be planting another plant that will provide a bit of shade to your hosta. Plant a large perennial or shrub for protection.
You can avoid this quite often by planting a lighter colored hosta. A bright chartreuse hosta like ‘Dancing Queen’ can handle the sun. Darker green and blue hued hostas do not tolerate as much sun.
Leaves Covered in White Powder
Powdery mildew is a fungus that covers the leaves of plants in a powdery film. Take your finger and run it along the leaf. If the powder comes off, it’s powdery mildew.
Prevention is definitely the way to go with powdery mildew. Make sure the hosta is in enough light that its leaves can dry out completely between watering. Water without spraying the foliage (drip hoses are great).
Make sure it is in nice light free draining soil. Also make sure there is a bit of space between your hostas and other hostas or plants so that there is adequate airflow.
Of course, this bit on prevention must be thoroughly annoying if you already have powdery mildew and just want to get rid of it. Not to worry, there are products on the market to deal with mildew. A fungicide spray purchased from a garden center works great. Make sure it includes powdery mildew on the label. Use according to package directions.
Leaves With Holes
Leaves chewed full of holes are usually caused by hosta’s nemesis, snails and slugs. Hostas thrive in damp and shady conditions. So do slugs and snails. There is also not much you can do about a period of damp and rainy conditions.
There are many methods for ridding snails from your garden. There is the very popular saucer full of beer method. Where you put a tray if beer out and it lures them in and you toss them out. This needs to be closely monitored to be effective.
Putting rings of crushed egg shell around the plants works as well. It cuts their soft sluggy bodies. But it will need to be reapplied throughout the season. You can also try and plant the thicker leaved hostas, like ‘Blue Angel’s or ‘Brother Stefan’.
Slugs and snails don’t chew those thicker leafed hostas as easily. Although, if there’s no other options, they will munch them.
My favorite method for ridding snails and slugs is snail bait. I purchase a bag of small cylindrical pellets from my garden center and I sprinkle it through the garden. The slugs disappear. Apparently they eat it and hide to die. But there are no slug corpses lying about and my hostas remain slug free.
This is a big one. Hostas are a salad bar for rabbits and deer. If all you have left of your hostas are eaten stems, they are probably being eaten.
Rabbits and deer love munching on hostas, there is no doubt about that. There are a few things you can do to try and save them.
There are animal deterrent sprays you can purchase from the garden center. Spray the foliage of your hostas with is and animals should avoid it. You will need to reapply any time it rains or you do any overhead watering.
Fences are effective, albeit expensive. But creating a fenced in garden will deter deer, and maybe rabbits depending how tight the fence is.
However, if this becomes an ongoing problem and frustration, it might be time to replace your hostas with something animal resistant. Rhubarb has the big hosta leaf feel, but deer don’t munch its toxic leaves. Or bergenia has waxy leaves that look great in the shade. They will eat the flowers off them but leave the leaves behind.
Sticky leaves on a hosta could be from a couple of different pests.
Aphids secrete a sticky sap. While they probably won’t kill your hosta, they are unsightly and can lead to other diseases and pests attacking.
Aphids usually attack a plant that is weak. So after you deal with the infestation, try your best to identify and correct the environmental problem (lack of water, heavy soil etc). I find aphids often appear on the stems of the flowers of hostas. I will just prune those off. Then I will spray the hosta with an insecticidal soap. Repeat weekly as needed.
Mealybugs also leave a sticky substance known as honeydew. Black mold can begin to grow as a result of this sticky substance. So it’s best to control this infestation quickly. Mealybugs can be difficult to control.
If there aren’t too many on the plant spray then off or dab them with a cotton swab dipped in rubbing alcohol. If it is a larger infestation go straight to the insecticidal soap. Keep treating weekly until the infestation is gone.
Mottled leaves are bad one for hostas. If your hosta leaves are taking on a mottled appearance you may have Hosta Virus X. Mottled leaves are the main symptom to notice. But also Puckered leaves and necrosis of the leaves can happen along with the mottled appearance.
Do not prune out these discolored leaves. This will only spread the virus further. Unfortunately there is no treatment for the virus. The plant should be dug up and disposed of as soon as the virus is identified. Do not let it spread to your other hostas.
Since there is no treatment for this disease, be sure to check over plants purchased from a garden center or nursery carefully. Choose healthy plants with evenly colored foliage. Also, check over plants received from garden trades or neighbors. Lots of diseases, weeds, and pests are spread by well-meaning gardeners.
While puckered leaves along with other symptoms can be a sign of a more serious problem (hosta virus X), Puckered leaves on their own may not be a problem at all. This is why it is important to really check and rule out disease before ripping out your hostas.
There are many, many varieties of hostas. I know sometimes when we purchase them from the garden center they don’t always say the exact variety on the tag. Sometimes it just says Hosta Spp. I like to try and figure out the variety.
Some varieties have thick corrugated leaves. ‘Brother Stefan’ hosta, for example, has thick corrugated leaves that can appear puckered. They look even more puckered when the new leaves are unfurling. This is normal.
There is another reason for puckering hostas. Some of the hostas with various shades of green in them can be affected by what is known as the drawstring effect. This occurs in varieties that have a light colored margins and darker centers (eg. Hosta ‘Brim Cup’).
This occurs because the inner portion of the hosta has more chlorophyll and produces energy faster than the colorless white margin, so the inner leaf is growing fast and will push the edges up resulting in a cupping effect.
The only thing to be done about this is to purchase hostas that are a single color or have thinner leaves. Or try planting your puckered leaf hosta in an area with less light to slow the growth of the plant down and hopefully avoid the puckering.
Yellow Margins and Rotten Stems
Yellow margins along the lower leaves accompanied by mushy spotted stems and white threads on the petiole is a sign of petiole rot.
This is a terrible fungus to get in your hostas. It starts with yellowing margins and rotting stems and ends with your whole hosta rotting and falling off at the base of the plant.
Unfortunately, there is not much treatment for this disease. Prevention is key. Make sure to keep mulch away from the stems of the hosta. Mulching is good, but take the time to push it back so it is not touching the stems. Clean and sanitize garden tools after use. This will prevent spreading all sorts of diseases to various plants.
Finally, if this has killed your hostas. Dig and remove at least 6 inches of the soil and replace with fresh soil. According to Iowa State University, certain varieties are less susceptible to petiole rot. ‘Halycon’, and ‘Lemon Lime’ are among the tolerant varieties mentioned.
Browning and Dying in the Fall
Hostas are one of the last plants to rise in the spring, and one of the first to die off in the fall. This one is perfectly normal. Hostas will turn to mush once a frost gets them. They are finished for the year.
You can clean these up in the fall, but I prefer to clean them in the spring and let all the beneficial bugs overwinter in their leaf litter. Unless the leaves had a disease or pests, such as powdery mildew or aphids, then I will dispose of their fallen leaves as soon as possible.
Large Irregular Spots on the Leaves
Large, regular spots that are surrounded by dark borders is the tell tale sign of anthracnose. Anthracnose is a fungal disease that affects hostas. While it normally isn’t fatal, it ruins the most important aspect of a hosta, they’re beautiful ornamental foliage.
Prevention is key for this one. Avoid getting the leaves wet on a hosta. I know this isn’t possible entirely because, well, it rains. But there are times when spraying the leaves is avoidable.
I water my hostas by using a drip hose that snakes through the garden bed. I turn it on for a few hours a week and it waters the soil directly. If you are using an overhead sprinkler, water in the early morning. This allows the sun to dry off the leaves quickly. If you water at night, the leaves sit wet all night long and give the fungus a chance to settle.
You can simply snip off any leaves affected by the fungus and let new leaves grow in. You can also apply a fungicide that contains chlorothalonil.
Dull Leaves with a Film on Them
At first you might notice dull, mottled appearing leaves. Then upon closer inspection a silky web is covering the leaves and flowers. This is a sure sign of spider mites.
Spider mites are more annoying than fatal. A good blast with the hose and a wipe of all the leaves every couple days might be enough to get them off your hostas. If it does not work I will spray the leaves with an insecticidal soap or miticide. Use according to the package directions.
Spider Mites usually attack weak plants, so make sure you have your hostas growing in their ideal conditions.
Brown Stripes on Leaves
Brown stripes on your hostas leaves are a sign of foliar nematodes. These are very tiny (less than 1mm long) worms that feed on hosta foliage. They cannot even be seen with the eye, they need to be viewed under a microscope. However, you can definitely see the damage they cause.
Unfortunately, this one does not have many treatment options. The best thing to do is to inspect plants before purchasing. Make sure the foliage is healthy and without stripes of brown leaves.
Watering hostas without spraying the leaves will also help reduce the chances of foliar nematodes taking hold of your hostas. Use a drip hose instead of an overhead sprinkler. Water early in the morning as opposed to the evening so the leaves quickly dry off in the sun.
I have been reading from various sources, such as Iowa State University, and The American Hosta Association, that there is a hot water method that can be an effective treatment. It involves digging up your hostas and running them under 120-130F water for 10-20 minutes to kill the eggs.
Be very careful as you don’t want to kill your hosta’s roots in the process. Drench them in cold water after the hot water. The American Hosta Society recommends doing this while the plant is dormant, so dig it up before it starts growing. Once the ground is thawed enough to do so.
Be sure not to cross-contaminate. Sterilize all tools and wash your hands with soapy water after touching any affected plants.
Hostas are one of my favorite garden plants. The big leafy foliage in a wide range of colors and patterns is hard to beat. For the most part, hostas are easy to care for and are low maintenance. They make shady areas lush and interesting. With a little TLC and some quick action, you can ensure your hostas remain problem free!