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Chenoa0125 Sanderson, FL Jul 07, 2015

i have 2 questions regarding 2 plants I'm having an issue with. #1 my parsley leaves are turning a pinkish purplish color. They're in raised beds but not growing any more and leaves are changing colors.

#2 my tropical milkweed leaves are turning yellow with black spots in them. I was wondering if anyone has any advise to these 2 problems that have come up all of a sudden bring as I have been growing the parse my for over a month and have had the milkweeds in my butterfly garden for atleast 2 months with no problem. Any advise would be great. I live in Sanderson Florida zone 8 if that helps. We had not got any rain as of late & was watering myself now we've had almost 2 weekends of rain.

Thanks

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tapla Bay City, MI(Zone 6a) Jul 07, 2015

It's likely you're seeing the purple coloration as the result of a stress factor related to a nutritional deficiency. A common cause of purple leaves is a deficiency of phosphorus (P) because P is required to make ATP and ATP is needed to turn sugars to starch and to load sugar into phloem for transport to plant organs. No P = no ATP = no move sugars/starches = anthocyanin (purple pigment) builds up = plant turns purple. The most frequent cause of a P deficiency is cold soils, which is why so many plants planted out too early turn purple.Technically, the purple coloration is probably related to a breakdown of chloroplasts in the leaf surface and the subsequent expression of the flavonoid anthocyanin and the carotenoid xanthophyll/ lutein. It's possible that the right fertilizer will "erase" the problem, but there is a rub. You'll need to determine what the problem really IS, and it's not likely you'll be able to do that w/o a soil test. Additionally, nutritional deficiencies aren't the only thing that can cause a build-up of anthocyanin. Virtually any environmental influence that puts the brakes on growth and the accompanying use of sugars, but does not limit sugar production (photosynthesis) can cause an anthocyanin buildup and purple leaves. If only the outer edges of the leaves are purple, it may be a K or Mg deficiency. If the center of the leaves are also purple, it could be too much Ca in the soil or the result of too much water in the soil blocking uptake of P and/or Mg.

I realize what I said isn't going to help you much, but w/o more info, there's not much more I can offer. For example - are you fertilizing? with what? how much/ how often? What is the composition of the soil in the raised beds? How old is the soil? How is the drainage? Are the beds over clay and did you dig into the clay when the beds were created?

How is the drainage where the MWs are? Post pictures of the damaged foliage?

Al

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