Hellebores (Helleborus spp.) provide much-needed color at the tailend of the bleak winter months.
These colorful plants are some of the earliest to bloom in Zones 4 to 9, and thrive in shady beds and borders.
Normally pretty low-maintenance, cultural requirements include well-draining, loamy soil, and protection from the sun’s harsh rays in summer.
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The plants don’t tend to suffer from many pest and disease issues, but one of the most common signs that something is wrong with hellebores is browning leaves.
Sometimes it’s just a few brown specks and sometimes it’s the entire leaf that is discolored, but however it appears, brown foliage always points to problems.
Usually, it’s caused by an environmental issue like excessively cold weather or too much sun, but sometimes discolored foliage is a symptom of disease.
In our guide to growing hellebores, we cover how to cultivate plants in your landscape.
If you’re seeing browning foliage, here’s the list of possible causes that we’re going to discuss:
9 Causes of Brown Foliage on Hellebores
In general, individual leaves that are more than one-third brown should be removed from the plant immediately, as they will not recover.
Even if the entire plant looks dead, remove the foliage and be patient, the roots may still send up new growth.
1. Aphids
Aphids are a part of the garden ecosystem pretty much every year. If they aren’t snacking on my roses, they’re nibbling on my rose of Sharon.
Much of the time, they don’t do a tremendous amount of damage but these pests can spread diseases and cause stunted growth.
There are several species of aphids that feed on Helleborus, but the hellebore aphid (Macrosiphum hellebori) is the major player.
This particular species is green or whitish-green and they tend to cluster around the flowers and along the stems.
Their feeding can cause the leaves to turn yellow or brown. They also secrete waste called honeydew, which is a sticky substance that can attract sooty mold.
My first line of attack is always to blast the insects off the plant with a strong stream of water from the hose.
You can also introduce beneficial predators like lacewings. Lacewings love nothing more than to devour a big, ugly, aphid infestation.
Green Lacewing Larvae
You can find green lacewing larvae available at Arbico Organics.
If that fails to keep it under control, break out the insecticidal soap and spray your plants liberally according to the manufacturer’s instructions.
Our guide to eradicating aphids has more information.
2. Black Death
The name sounds scary, and it’s not an exaggeration. Hellebore black death is one serious disease.
Likely caused by Helleborus net necrosis virus (HeNNV), symptoms include black streaks, netting patterns, and stunted, distorted growth. The leaves might turn brown, with black streaks.
Since the virus is spread by the hellebore aphid (Macrosiphum hellebori), it is important to keep these pests under control.
If your plant is infected, all you can do is remove it and dispose of it in a sealed bag in the garbage, not your compost as there is no cure.
You can learn more about hellebore black death here.
3. Downy Mildew
Downy mildew is a disease caused by oomycetes, which are water molds, that impacts many different species. In hellebores, it’s Peronospora pulveracea that causes the disease.
These pathogens need moisture to survive and reproduce, which is why this problem is common during wet weather or on plants that are grown in crowded conditions or watered from overhead rather than at the soil level.
Wet foliage and lack of air circulation create ideal conditions for downy mildew.
It shows up as brown and black speckling on the leaves. You’ll also see a fuzzy mold-like coating on all parts of the plant.
Eventually, the leaves will turn brown and fall off the plant.
Of course, it’s best to act quickly if you see evidence of this disease. Prune off any symptomatic areas and then spray the plant with a broad-spectrum fungicide.
There are lots of good fungicide options on the market, from copper to those that contain the beneficial bacterium Bacillus amyloliquefaciens strain D747, like Monterey Complete Disease Control.
Monterey Complete Disease Control
If you’d like to try the latter, pop on over to Arbico Organics to pick up 32-ounce hose-end or ready-to-use bottles, or an eight-ounce, pint, or gallon concentrate.
Spray the plant every few weeks until new, symptom-free growth develops.
You can help prevent downy mildew by watering at the soil level and keeping plants well-spaced from other plants or objects.
4. Leaf Spot
If there are brown spots on the foliage, it might be leaf spot. This disease is caused by the fungus Microsphaeropsis hellebori (syn. Coniothyrium hellebori) and is pretty common.
As new growth emerges in late winter or early spring, you’ll see round, dark brown dead patches develop.
These brown, dead areas usually have a pale border and concentric rings, and might persist on the leaf, or centers might fall out.
They can also grow and connect, killing the entire leaf. It can impact the stems and flowers, too.
To control leaf spot, remove any symptomatic material from the plant using sanitized pruners or scissors.
5. Low Temperatures
Depending on the species or cultivar, some hellebores can survive extremely frigid temperatures.
H. niger, for example, is happy in the Alps in temperatures the equivalent of USDA Hardiness Zone 3. Freezing temperatures won’t even make them flinch.
But not all hellebores are so tough. Corsican, H. argutifolius, is only hardy to Zone 6.
So while some kinds will be fine down to -20°F, others won’t be.
If the temperatures drop below what your particular type can handle, it might not kill the plant, but it could turn the leaves brown.
Be aware of the particular temperature tolerance of the type that you’re growing and if it drops below that, provide the plant with some protection or be ready to trim off any damaged leaves.
Most plants won’t die if the temperature drops just below their preferred range, but there will be some damage. If it dips too much for too long, though, it could kill the plant.
6. Overwatering
When you overwater plants, it drowns the roots and causes them to start rotting. When this happens, the leaves will turn brown, often with a soggy texture.
This is just a prelude to the entire hellebore collapsing and dying.
So, yeah. Don’t overwater.
If your plant seems to be sagging and soggy, dig down a little and look at the roots. If they’re soggy and soft and maybe smell bad, it’s root rot.
Stop watering and let the soil dry out. Prune off all the dead leaves.
Then, reduce your watering frequency by half. If the plant still isn’t thriving and sending out fresh growth after a few weeks, soak the soil in copper fungicide.
Bonide Liquid Copper Fungicide
This will kill any pathogens potentially contributing to the rot. You can pick up a bottle of 16 ounce concentrate at Arbico Organics.
7. Prolonged Freeze
Though these plants can certainly tolerate an extended freeze, if the weather drops below freezing for several days and the plants don’t have a layer of snow to protect them, it can damage some of the leaves.
This can happen even if the temperatures don’t drop below their preferred range. A freeze causes the cells in the plant to swell and burst, which can result in browning.
If your hellebores look a bit ragged in the spring after a rough winter, this is often the reason.
The fix is to remove the brown leaves. In the future, if you know there is an extended period of freezing weather on the horizon and there’s no snow on your plant, go out there and put a cardboard box or something similar over them.
8. Too Much Sun
Hellebores don’t like a lot of direct sun.
I had one planted in my yard under a privet (Ligustrum spp.) that had been trained into a tree.
I gave the privet a hard prune one year to get it back into shape and within a few weeks, my hellebores were looking exceptionally sad.
Turns out, I had exposed them to direct sunlight that they hadn’t been hit with before.
If I had gradually introduced the plant to additional sun, it might have been fine. But I didn’t. One day it was tucked into dappled sunlight and the next it was in direct sun for over six hours.
Within a few days, the leaves had turned crispy brown with just the stems and leaves that were shielded by upper foliage still alive.
In this case, I left the brown leaves in place to protect the lower leaves until the privet could grow out a bit and provide some shade.
You can do the same, but if the leaves start to turn mushy at any point, get rid of them. Crispy leaves are safe to allow to remain in place, but mushy ones aren’t.
Try to expose your hellebores to more light gradually if you need to. Otherwise, keep them in the type of exposure they prefer, which is typically morning sun or filtered sunlight.
9. Urine
I can’t tell you how often someone brings me a picture of their dying plant and we eventually figure out that the problem was dogs.
Now, I love my pups, but they can ruin some plants. If your hellebores are growing along a walkway or an area where your dogs frequently visit, it’s entirely possible that it’s urine turning the leaves brown.
Urine is concentrated and it essentially burns the foliage. That’s why you see brown patches in the lawn wherever a dog pees.
So if you see browning foliage along a walkway with the rest of the plant away from the walkway still green, consider that your hellebores might be the local canine potty spot.
It’s Easy Being Green
I have a hellebore with the most gorgeous brownish-pink flowers. In that case, brown is a welcome addition to my garden. Brown hellebore leaves? No thanks!
What’s troubling your hellebores? Were you able to figure it out? Or maybe you’re looking for a little extra guidance? If so, let us know what’s up in the comments section below and we’ll do our best to help.
And for more information about cultivating hellebores, put these guides on your reading list next:
