Brown leaf tips
About four months ago, I bought a small Columnea orientandina, which consists of two plants potted close together. Soon afterward I noticed that the leaf tips on the larger plant were turning rusty brown, though not drying up. (I can't remember what the smaller plant was doing.) At first I thought that might be a characteristic of the plant (it's not unattractive); then I decided I was overfertilizing. Now I notice that the smaller plant is turning limp and shriveling up. Unfortunately, I didn't quarantine the plant when I received it. Does anyone have any suggestions? Should I be panicking?