How Do You Treat Southern Blight on Hostas?

Southern Blight is a fungal infection that can turn your beautiful hostas into dying, wilted plants. The sight of Southern Blight can be bad news for the overall health of your garden and strike fear in many gardeners. Are there any steps that can be taken to save your hostas and get rid of Southern Blight?

To treat Southern Blight on Hostas, first, remove soil and hostas from the infected area. Replace the infected soil with new soil. For the Hostas, cut off any areas that show signs of Southern Blight on the stem and leaves of the plant. Following this, you can replant the Hostas in the soil.

In areas where Southern Blight thrives, it can be difficult to keep the fungal infection out of the garden and away from any plants. Finish reading to find out how to treat Southern Blight that has infected your Hostas.

How Do You Treat Southern Blight?

There are several actions that can be taken to prevent Southern Blight from compromising or killing hostas, as well as any other plants in the garden that are susceptible to Southern Blight. However, it is important to be mindful of the fact that once Southern Blight establishes itself in the garden, it may be very difficult to remove it. The fungus can remain in a garden for long periods of time, and it quickly spreads.

What does blight look like on hostas?

Knowing this, it is vital that the Southern Blight is treated as soon as it is noticed. There are several symptoms of Southern Blight that will show in your garden or on your Hostas.

  • White, thread-like material (the fungus) will be present in soil and on the Hosta’s stem
  • Leaves on the hostas will begin wilting, turning yellow and brown as they die
  • Sclerotias, mustard-seed sized fungal growths will appear on the Hosta and in the surrounding soil

If these symptoms go unnoticed, within a week the fungus will eventually start wilting the hosta’s leaves and producing sclerotias– small, mustard-seed sized growths that spread in the soil and on the plant.

Once the Southern Blight is seen, the first action to take is to remove the soil and plants in the area of the infection. When removing soil, try to go a few inches below and also beyond where the hostas roots stop to ensure its removal. The soil should be discarded and replaced with new, non-contaminated soil.

For the plants, the action to take depends on the state of the plant. If the fungal infection is caught early, before leaves are wilting and sclerotias are present, areas on the stem that show signs of infection should be cut off. The leftover hostas should be left out in the sun to dry as Southern Blight thrives in moist environments.

If the infection has begun to kill the hosta, and the leaves are wilting, the plant should be discarded. The unfortunate nature of Southern Blight is how rapidly it kills plants that are susceptible to the fungus.

What Causes Southern Blight?

Southern Blight is a fungus, and fungi thrive in certain conditions:

  • Warmer climates
  • Areas with high levels of moisture
  • In soils and plant debris

Hostas in gardens of warmer climates are highly susceptible to Southern Blight. Hostas are also plants with a heavy abundance of leaves. Because of this, soil surrounding hostas has a harder time drying out as hostas create so much shade around them.

Southern Blight originates in soil or plant debris and spreads from there. It can invade a garden via another plant being introduced to a garden, runoff from nearby water sources, or from soil that is contaminated. In general, Southern Blight will come from other sources that are already infected.

How Do You Prevent Southern Blight?

With how severely Southern Blight can affect hostas, it is important to implement preventative measures to reduce the chances it reappears.
There are practical prevention actions one can take to keep Southern Blight from infecting hostas, including the use of high-quality mulch, keeping plants in the garden spaced out from one another, and using fungicides.

Mulch is a collection of plant materials that can be spread atop a garden’s soil. Using mulch in the right quantity can prevent diseases from culturing in a garden. Thus, using a high-quality mulch can reduce the likelihood that Southern Blight finds a home. A high-quality mulch, such as shredded bark, is less likely to be contaminated by other viruses or fungi upon purchasing.

Hostas, because of the abundance of leaves, creates a great deal of shadow-cover over soil. Bunching hostas together creates a moisture-rich environment as the sun cannot reach the soil to reduce its moisture. In keeping a reasonable amount of space between hostas, sunlight can touch more of the garden’s soil and reduces moisture around hostas. Recall that fungal infections like Southern Blight thrive in a high-moisture environment.

Finally, fungicides can be used to try preventing Southern Blight from starting to grow and spread. This is an option that is more expensive and chemically reliant. It is effective at preventing fungi from starting to grow. This solution is more viable for smaller gardens or landscapes where large quantities of fungicides are not needed.


As hostas are so susceptible to Southern Blight, particularly in warmer climates, keeping track of your hostas health and growing progress is important in preventing infection. The ways in which one can prevent its presence or stop it from continuing to infect other plants boils down to having a quality garden. Using high quality soil and mulch, knowing signs of infection, and tending to infected plants are all useful and lead to an overall healthier garden.