Q. Dear Peter! Thank you for your column in the Tribune. My problem is this: I have several Oxalis plants; I think they are Oxalis purpurea. They provide beautiful mounds of green with their rose pink blossoms. Around right now though some of the mounds’ leaves turn brown and curly. What causes this? Our garden tends to be moist – on a hillside. Also how do you get rid of buttercup? Karen Morris – Tacoma, WA
A. Unless you have a warm microclimate in your garden is unlikely if that you have Oxalis purpurea since that a South African native and not generally hardy in the Puget Sound region. Oxalises are notably pest free regardless of which species you have. It is difficult to say exactly why some leaves are turning brown and curling. I could be something cultural. The only disease I know of related to Oxalis is a species of rust that also uses corn as a host. It does not sound like the problem is threatening to the plant so I would just remove and dispose of the effected leaves.