| My photinia used to be a lovely red aat the tips and bright green at the base. For several months, however, it has slowly been turning pale and yellowing on the bottom leaves. I water it plenty, but it doesn't help. What can I feed it to make it look healthy again? |
| Yellow leaves can be caused by many things including lack of nitrogen, insufficient light, water-logged soil (plant roots need oxygen to thrive), dry soil, or iron deficiency. If the older bottom leaves are yellow, but new growth is green, it's usually a lack of nitrogen. If new leaves are yellow, with green veins, it's usually a lack of iron. Soil should be kept moderately moist (but not wet). Finally, transplant shock can contribute to yellowing. If new growth shows up as green, that might be the problem. Try to isolate each of these possibilities one at a time to determine the problem. Iron chlorosis is a problem in the desert for non-native plants. Chlorosis is recognized by new leaves that are yellow, while the veins remain green. If the condition is severe, the entire leaf may be yellow. Although iron is present in the soil, it is not always in a form that non-native plants can use. (Native plants seldom suffer from iron chlorosis.) Overly wet soils are depleted of oxygen. (As water fills in the minute spaces between soil particles, air moves out.) Plant roots need oxygen to absorb iron in the soil. To help prevent chlorosis, always water slowly, deeply and infrequently. Soil with a high pH (alkalinity) also inhibits iron absorption. If you are using correct irrigation methods and symptoms are still present, apply iron chelates or ferrous sulphate to the soil. Both are readily absorbed by a plant?s roots. In your case, I'd suggest making sure you aren't overwatering. Water deeply and as infrequently as possible. Next, I'd try a nitrogen fertilizer, since the lower leaves on your plant are turning yellow. Good luck! |
