Ten days ago I purchased a Cordyline Red Pepper plant and today noticed some brown spots with light yellow-green centers and surrounded by pale yellow-green zones on one of the leaves. The brown spots are about one eighth of an inch in diameter. The leaf is about nine inches long; there are two spots near the tip and two at three and six inches, respectively, from the tip. I removed this leaf. No others appear to have brown spots.

I am growing this plant as a houseplant since I live in zone 6b, and it will be cold here for several more months.

What might these brown spots be (infectious?), and should I be alarmed?

The yellow ring around the brownish bull's eye usually indicates a fungal problem. This has been such a cold and wet winter which is ideal for fungus. You did the right thing by removing the leaf. I would not panic but do watch it carefully. Do not overwater while it is in the house and no fertilizer until you see new, healthy growth.

I meant to add, you can apply cinnamon to any cut surfaces where you remove leaves. It has natural anti-fungal properties. Put a bit on a spoon and dab it on any cut surfaces with a q-tip.

ardesia said:I meant to add, you can apply cinnamon to any cut surfaces where you remove leaves. It has natural anti-fungal properties. Put a bit on a spoon and dab it on any cut surfaces with a q-tip.

Thanks for this great tip, Alice! I just applied some cinnamon to the cut surface. The leaf was attached by what appeared to be a hollow stem that was curled and that had very little plant material (only a thin rim of tissue).

Don't worry, Carol, it is not a fungus, although those leaf spots do mimic fungal diseases. Cordylines are very sensitive to minerals salts that can build up in soil and cause leaf spotting. Fluoride is one mineral salt, but not normally a problem at the concentration levels added to water supplies. However, hard water is high in various mineral salts and can cause Cordyline leaf spotting. Using too much fertilizer or perlite can also affect this plant. Finally, be aware that if the soil becomes too dry, the concentration of any mineral salts in the soil will increase. That doesn't argue for keeping the soil constantly wet, but it does mean it is important to never let the soil get too dry.

Frankly, it is hard to avoid some leaf spotting with potted Cordylines, especially on older leaves. Use filtered or distilled water if you have a water quality problem. Skip fertilizer altogether. And water your plant thoroughly as soon as the surface of the soil feels almost dry.

Thanks, Will, for this good news and your excellent, detailed guidance.

The spotted leaf was indeed an older one, i.e., the lowest on the stalk. I have untreated acidic well water with lots of dissolved iron.

If you use distilled or filtered water that should go a long way to solving the problem.