Oxalis – Rust Disease
Q: I have an oxalis with the burgundy leaves and pink flowers. In late winter and early spring (through May) it looks great. Then with warmer weather the leaves get what looks like orange rust spots on them and they wither. Do you have any suggestions?
A: Your oxalis has a fine case of oxalis rust, Puccinia oxalidis.
My outdoor oxalis comes down with it every year but seems to survive year to year just fine.
I suppose you could spray with myclobutanil (Immunox) or chlorothalonil (Daconil)…but you may find that you can cut and remove the leaves when the rust gets bad and still enjoy a month of oxalis flowers and foliage beforehand.
Oxalis leaves naturally disappear in summer heat. The rust just hastens their exit.