Diseases such as bacterial and fungal leaf spots and heavy sap-sucking insect infestation can cause ivy leaves to turn black. Excessive watering can also cause ivy leaves to turn black by causing phytophthora root rot, which causes ivy leaves to turn black.
You must consider the humidity of the leaves as well as the careful application of fertilizer. The blackening of the leaves results from fertilizer burn, which occurs when too much fertilizer is applied.
In this article, I will discuss all possible causes and how to solve them. You can’t get the blackened leaves back to normal, but you can keep
Contents
1- High Humidity Favors Fungal Growth
Fungal diseases like fungal leaf spots and mildew thrive in damp, humid conditions.
If you keep your English ivy in a closed-off room or patio area, the plant will be subjected to a high-humidity microclimate due to the lack of air circulation.
Solution
Relocate your English ivy to a location with consistent airflow, and it will respond better to its natural surroundings.
Keep your English ivy 1-2 feet apart from other plants to reduce the effect of high humidity. In addition, it will protect the plant from the transpiration effect of the surrounding plants.
2- Diseases Cause Black Leaves on Ivy Plant
There are over forty different pathogens that can cause disease in English Ivy. Most thrive in damp places with little airflow and can quickly spread to other plants.
Keep your Ivy in an area with good airflow and low humidity. It’s also a good idea to thin out areas with too many leaves. It might hurt to cut off thick, lush leaves, but a well-trimmed Ivy will be healthier.
No matter what’s wrong with a sick plant, it’s best to put it in quarantine. But, unfortunately, it doesn’t take much for one sick plant to become many.
Here are some of the more common Ivy diseases to watch for.
Bacterial Leaf Spot
Large brown spots can be seen on the leaves of infected ivy plants due to the bacterial disease known as bacterial leaf spot. They start as small, bumpy spots between the leaves but quickly grow until they cover the whole leaf.
The blotches can be waxy or greasy to the touch and develop water-soaked, blister-like lesions. Over time, the entire leaf falls off, and a sick plant can lose all of its leaves.
Solution
Start by cutting off any diseased leaves. Wear disposable gloves and remove any infected leaves with clean, sterile shears. Toss them in the trash instead of the compost bin, as doing so could encourage the reemergence of the fungus spore.
After that, you must wait and let the Ivy fight off the disease. Keep it well-lit and well-watered; if the infection is too bad, you should treat it with broad-spectrum plant medicine (Amazon link).
This won’t eliminate the leaf spot, but it will keep your Ivy safe from opportunistic diseases that might otherwise strike while it’s weak.
Fungal Black Spots
The fungal black spot is precisely what you’d imagine – patches of dark, papery tissue that speckles the leaves. They often show concentric rings and may start a pale brown before darkening. Various fungi cause it, but the Colletotrichum trichellum species is the most common.
Solution
Because the fungal disease spreads quickly, quarantine the Ivy immediately. As with bacterial spots, carefully remove and dispose of any diseased leaves. Use disposable gloves because spores can easily lodge in leather or cloth gloves.
If the infection is severe, with more than one or two infected leaves, I recommend using a copper-based fungicide. Always follow the instructions and keep those gloves on until the treatment is finished.
Phytophthora Root Rot
Root rot is always possible when leaves start to blacken. Ivy needs free-draining soils that retain moderate moisture, a tricky balance to meet. If you over-water, the stage is set for root rot, and Phytophthora is the most complicated root rot to break. Caused by a tiny microbe called an oomcyte, it destroys the Ivy from the soil while also causing the most tender new leaves to blacken and die.
Solution
Ivy plants die most of the time due to phytophthora root rot. But if you can spot the disease before it worsens, you can keep your ivy plants alive. Here are the steps to follow:
- Remove the entire plant from the pot and inspect the root system, removing some soil around the roots.
- Infected roots will be dark and soft, whereas normal roots will be light and firm. Cut off the part that’s infected.
- Get rid of the cut portion and immerse the entire root system in a fungicide solution. You must also treat the soil with a fungicide or hydrogen peroxide solution, which you can apply similarly to watering the plant.
- Repot with fresh soil, including vermiculite and perlite, is preferable to promote oxygen flow and drainage capacity.
- Then, place the newly repotted plant in a well-ventilated area to help fight fungal diseases.
- Place 2-3 feet away from the other healthy plants after the above treatment.
It is always best to avoid the conditions that lead to root rot in the first place. You can prevent them if you carefully water your plants and ensure they drain well.
3- Applying Fertilizer During Hot Weather
Sometimes you may be tempted to use more fertilizer to encourage vigorous leaf growth in your ivy plant, but doing so can make the leaves turn black.
A nitrogen-rich fertilizer added to a potted plant’s soil will dissolve into the water and spread throughout the soil.
The Ivy will absorb as much moisture as it can during hot spells. The excess nitrogen builds up in the leaves much faster than the plant can use it. As a result, the leaves suffer chemical burns and turn black.
Solution
Do not put fertilizer too close to the roots because they will burn and turn black if they come in direct contact with the fertilizer.
Fertilizing the Ivy in the middle of the day during the summer will only speed up its growth and cause you to water it more often. They thrive when only fertilized once a month, preferably with a foliar fertilizer.
This prevents the Ivy from depleting the soil of nitrogen when it takes as much water as it needs. It’s best to spray the leaves first thing in the morning.
4- Sucking Insects Wreaking Havoc On The Leaves
The tightly overlapping leaves of Ivy provide a very inviting home for sap-sucking insects. Unfortunately, while they are generally pest-free, even the toughest plant can become lunch for the usual suspects.
So be on the lookout for the following:
| Pest | Appearance |
| Mealybugs | Small white or gray fluff balls. Sometimes secrets a sugary syrup called honeydew. |
| Spider mites | Small, around the size of a sesame seed. Red, brown, or gray. Produces silk. Clusters in nooks and crannies. |
| Aphids | Small green, brown, or white. Clusters in groups on stems and leaf veins. Secretes honeydew. |
| Scale | Small shield-shaped beetles. It appears as a small brown bump on the stem that lifts away when scraped with a nail. It also secretes honeydew. |
Solution
The first step, as always, is to move your Ivy away from other plants, as insect pests like to jump from plant to plant.
Next, inspect the rest of your collection as well – Ivy does not usually attract pests, so if an Ivy has a few, there are probably other plants nearby with a more severe infestation.
For minor infestations, the insects can usually be physically removed.
However, most will die if they are plucked or wiped away, and even tiny spider mites will die if they are washed away with a blast of water from a shower head or hose.
Neem oil is an excellent choice for more severe attacks. Adult insects will be killed if sprayed directly on the leaves.
Because eggs will be hiding in the soil or on the leaves, you’ll need to repeat the treatment every five days until it clears. You’ll also have to kill the newly emerged pests once they hatch.
5- Sooty Mold
Sooty mold can appear as a black powder on the leaves, which are fungal spores. It typically starts as isolated spots on the leaf and spreads to cover the entire surface.
Honeydew is a sticky substance excreted by sap-sucking scale insects, aphids, and whiteflies.
Because of the sugar content, it is naturally sticky. If you do not remove the fungal growth immediately, it will spread to the entire leaf.
How to Treat Sooty Mold
Remove the mold by scrubbing it with a toothbrush or tissue paper. If you are concerned about the appearance of the infected area, you can prune it.
To get rid of the sooty mold fungal infection, you must first get rid of the scale, aphid, and whiteflies.
You can physically remove them with rubbing alcohol or kill them with a spray-on pesticide such as neem oil. Ensure that no eggs or larvae are left on the underside of the leaves, or they will return soon.
6- Direct Sun Can Burn The Leaves
Ivy plants of European origin do best with moderate light levels. They’re a forest understory plant, equipped to make the best of very little.
The leaves will be burned if exposed to direct sunlight. A burn will first appear as a lighter patch of color, then turn brown or black as the tissue dries out and becomes permanently damaged.
Furthermore, the magnifying glass effect of a window will cause the leaves of your indoor English ivy to burn their delicate tissues and turn black if you place the plant too close to the window.
Solution
First, move the Ivy to a more protected area of your growing environment. Along the way, give the Ivy an excellent deep watering – a sunburn will result in a hot, thirsty plant, so a bit of cool water will help the Ivy recover.
Trim away any damaged leaves from the stem. Don’t be concerned if the Ivy appears bare afterward. It’s a fast grower, so it won’t be long before the new foliage emerges.