The Q&A Archives: New Guinea Impatiens Have Yellow Leaves
Question: For the second year I have planted New Guinea Impatiens in my front bed which gets sun until 2:00pm. They are in full shade for the rest of the afternoon. I had a problem with yellow leaves last year so we turned over the bed this year and added a "clay breaker", which was recommended by our garden center instead of a top soil for our area's all clay soil. My impatiens still have yellow leaves. We have had very little rain for the last month although I have watered regularly but not excessively. Please tell me why my New Guineas are yellowing. They were mature plants (6" high) when planted. I am ready to give up on them but love how they look when healthy.
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. (Lack of nitrogen is a more common problem than lack of iron.) Soil should be kept moderately moist (but not wet). Finally, transplant shock can contribute to yellowing. You didn't say whether you fertilized or not. I'd suggest trying a balanced fertilizer to see if that helps. Also, this fall or next spring, I'd recommend adding a generous layer of organic matter/compost to your bed. This will help with your clay soil, more so than adding top soil. I'm not sure what the "clay breaker" was, so can't comment on that. Continue to add organic matter every year, as it breaks down rapidly. Over time it will improve your soil's fertility and drainage.
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