7 Causes of Brown Spots on Hosta Leaves

A beautiful and well-kept garden is not only a source of visual pleasure but also a sign of the refined nature of its owner. To get excellent results, gardeners have to constantly increase their knowledge of plant cultivation.

The main cause of brown spots on hosta leaves is a disease. Fungal pathogens settle on the leaves and a brown or rusty spot forms in this area. If there are too many spots, the leaf may die.

Below we will go into more detail about the main reasons why brown spots appear on the hosta. You will also learn what to do in each case.

Cercospora Leaf Spot

The first disease that causes brown spots on hosta leaves is Cercospora Leaf Spot. In addition to the hosta, it also affects some other plants.

Cercospora Leaf Spot is usually active in summer during very hot weather. Sufficient humidity is also a prerequisite. Only if these two parameters are suitable will the disease begin to develop.

Small brown or rusty spots appear on the leaves of the hosta. Over time, they will increase and the leaf will die.

To cure the disease, spray the leaves with copper fungicide. You can find many variations of these products on the market. Use as directed on the label.

Repeat the spraying after a while. Also, clean up any plant debris near the hostas. Avoid overwatering the hostas. With proper care, the hosta will quickly recover from damage.

Phytophthora Foliar Blight

The next cause of brown spots is Phytophthora foliar blight. This disease is quite serious and can lead to the loss of the hosta, so do not ignore it.

It is most active when there is high humidity in the garden. This usually happens during summer rains.

Another cause of the disease can be overwatering the hosta and planting it in a very damp place. This also includes poorly drained soil.

If your hosta is infected with Phytophthora foliar blight, it will develop large but narrow brown spots. They usually spread along the veins until the leaf cracks.

To cure this disease, remove the badly damaged leaves. Next, spray the hostas with a multi-purpose fungicide. After 2 to 3 weeks, spray with copper fungicide.

Avoid overwatering the hosta. If it is growing in poorly drained soil or in a moist place, transplant it to a less moist place using organic matter to improve the soil.

Phyllosticta Leaf Spot

Phyllosticta Leaf Spot is another common cause of brown spots on hosta leaves. Warm weather is needed for the pathogens to spread, so the disease is usually active only in summer.

At the initial stage, the leaves look healthy, but the fungus spores are already parasitic on the leaves. After a while, dark brown spots appear in places where the fungus sprouts.

The next stage is the appearance of holes in the leaves with a brown edge. A severely damaged leaf may tear into pieces and shrivel up.

To correct the situation, the first thing to do is to remove the dead leaves. Also, clean up all plant debris near the hosta.

Spray the leaves with an aqueous solution of copper fungicide or use a fungicide designed to fight the disease. Repeat the spraying if new spots appear on the leaves.

Anthracnose

Anthracnose is a common name for a disease that can be caused by various pathogens. It usually affects hostas in warm and humid weather. Apart from hostas, hydrangeas are often affected by this disease.

When anthracnose affects hostas, the leaves become covered with pale brown spots with a grayish tint. But sometimes the spots can be dark brown or even red-brown. Parts of the leaf may turn yellow.

Use a multipurpose fungicide to cure the hosta. Fungicides containing chlorothalonil are also good against anthracnose.

To avoid this disease, do not plant hostas too close to each other. There should be a gap of about a foot between them. Always stick to proper watering of the hosta.

Gray Rot

Gray rot is a very common fungal disease. It affects many plants, including hostas. Leaves, stems, and fruits are susceptible to this disease.

If your hostas are too densely planted and it is very humid outside, pockets of this disease can appear on the leaves. It usually looks like large brown spots with a gray mold in the center.

Gray rot progresses quickly and can destroy almost all of the leaves. As a result, the hosta will be very stunted.

To cure this disease, remove the leaves that have gray rot. Next, spray the hosta with a copper-based fungicide. Repeat the spraying after a month.

Keep your garden clear of rotting vegetation. Plant hostas at a sufficient distance from each other. Avoid overwatering your plants, including hostas.

Rust

Rust is a disease that also causes spots on hosta leaves. The color of the spots is red-brown rather than brown and closely resembles the color of rust on iron.

At first, very small spots appear on the leaves, which will eventually grow to resemble small warts. By this time, the leaf usually turns yellow or pale.

This disease is caused by fungal pathogens and high humidity. A poorly ventilated garden also contributes to its development.

To treat rust, spray the leaves with a multi-purpose fungicide. A very large number of different fungicides can cope with this disease.

Clear the garden of dead vegetation and maintain proper planting spacing for hostas. Avoid watering the hosta over the leaves.

Herbicide damage

And the last possible cause of brown spots on hosta leaves is herbicide burn. This happens due to improper use of these products.

There is a misconception that herbicides kill weeds but not ornamental plants. This is absolutely incorrect. Weed killers can kill a hosta as well.

You or your neighbor may have used an herbicide and some of this product got on the leaves of the hosta. This will result in brown spots on the leaves.

If the herbicide has damaged the leaves, there is nothing you can do about it. With proper care, the hosta will eventually recover.

To avoid this, work with herbicides very carefully in the garden. Use plywood to protect ornamental plants from herbicides.