|Recently my hostas have colasped where all the follage is flat and looks bad. They are also showing yellowing in the leaves. I have liriope planted in front of them, which is also showing yellowing and the leaves look like they are drying out, even though they are watered regularly. I have thought the yellowing could be a lack of iron, but I have not yet added any iron supplements.|
|You're describing the symptoms of crown rot. This fungal disease, caused by Sclerotium rolfsii var. delphinii, can severely damage hostas within a week. Once established in an area, S. rolfsii var. delphinii is difficult to eradicate.
Symptoms begin to appear on hostas after prolonged hot, humid weather. The lower leaves turn yellow, then brown, and wilt from the margins back toward the base. The upper leaves may soon collapse, as well. Wilted leaves can be easily pulled from the crown, because they have been infected at the base of the petiole. The bases of these damaged petioles show a brown discoloration and mushy texture. With plants with less succulent stems, such as peony, stem bases may be girdled and then the leaves will become discolored and wilted, but the stems may not collapse. Ropy-textured white threads (mycelium) of the petiole rot fungus typically are present on the rotted tissue and surrounding soil.
There are no chemical controls for this problem so you may need to dig out the affected plants. Wish I had better new for you.