Yellowing of leaves, gardenia's, vinca's and roses?

what could be causing this? the gardenia leaves have been yellow since summer, the vinca leaves are starting to go yellow now. some of the rose bushes in a different location are also starting to yellow.





is this a problem with the soil acidity?

Yellowing of leaves, gardenia's, vinca's and roses?
Another possible cause of the yellowing is too much water. Yet another cause is chlorosis, meaning too little iron. Take a few leaves from each plant and bring them to a Master Gardener in your area. These are volunteers with a lot of experience with plants. You find them by calling your County Agricultural Extension (or similar department in your area.) Cut the leaves, or branches just before you leave so the Master Gardner can see them as they are on the plant, not dried.





As for acidity, you can have this tested by professionals, or use a cheap kit at a local garden center. The professional testing would include more elements of the soil, and give you a good report for what your soil and plants need for success. It's the best thing to do, but is expensive. Good luck.
Reply:It may be the soil. pH does effect how nutrients are taken up by the plant.





More likely it is a deficency. Nitrogen deficency can cause yellowing. It may be magnesium tho. That is usually what roses need. Add a little Epsom salts (magnesiun sulfate) to the water/fertilizer. Get a fertilizer for acid loving plants may be easier. Make sure it has 'micro nutrients', not just N-P-K but also S and Mg and other things.





Sometimes gardenias get yellowed from too much sun. But since it is also on other plants prob'ly not that.





Start with about half strength liquid fertilizer, a foliar feeding. That will get to the plants much faster. Water soluble fertilizer, like MiricleGro.
Reply:roses get yellow leaf when they are watered on the foliage. Just water the base, and this will not happen so much.
Reply:Not likely soil prob.Get a good spray for yellow spot for roses,and if you dont water reg. this can cause sim. prob.Also be carefull w/liquid fertilizers they can cause leaf burn,may be problem if you are useing.

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