Expert: C.L. Fornari - 5/17/2009

Question
Why are my blue lobelia flowers turning baby blue almost white. Is it a lack of sun? I live in zone 8b and was told that they should be shade plants for our area, is this right?

Answer
Julie,
Are the flowers that are fading the old ones? Usually this happens as the flowers age, but new flowers that are forming/opening should be darker blue.... that is, if they were dark blue to begin with. There are some varieties that are light blue from beginning to end.

Are your plants forming new flowers? If not, they may be in too much shade. In your area it's recommended that lobelia be in afternoon shade because that prolongs their life a bit. The bottom line is that this annual likes cool temperatures, and even in shade, when the temps get above 75 they start to decline.  The place that lobelia does best all summer is Alaska!

So, for your plants I'd do the following: if in full shade, move them to a place where they get a couple hours of morning sun.  Fertilize with a liquid fertilizer but only after watering them first and letting a couple of hours pass - never fertilize a thirsty plant!  Finally, hope for cool weather.

I hope this helps,
C.L.