Expert: C.L. Fornari - 8/2/2009

Question
WHAT IS CAUSING THE YELLOW LEAVES ON MY IMPATIENTS---I HAVE LOTS OF BLOOMS, AND THE FLOWERS LOOK VERY HEALTHY---BUT, THE YELLOW LEAVES??

Answer
Eloise,
The aswer depends on how many yellowing leaves you have. If there are a few (less than a quarter of the overall number of leaves no each plant) and they are at the bottom of the plants, this is probably just the plant shedding the oldest foliage in favor of the new. But if more than that are involved, it could be two things. Lots of yellowing leaves at the bottom of the plants is usually caused by the plants drying up in between waterings. If the plants dry up the roots shrink back, and then there aren't enough roots to support all the leaves so the plant sheds some.  If there are lots of yellow leaves over the entire plant, that's usually caused by too much water - when roots rot the entire root system goes, not just part, so the entire plant turns yellow.

Finally, pale yellow foliage can be caused by not enough nutrients or a pH that is so off that the plant can't absorb the nutrients that are there. If the entire plant is turning pale green, and you know that the soil isn't too wet, try a mild liquid fertilizer after watering the plants well. (Never fertilize a thirsty plant.) If that doesn't help, have a soil pH test done and tell the tester that you're growing impatiens in the bed.  Most Cooperative Extensions have a soil testing service.

all the best,
C.L.