Why are my gardenias leaves turning yellow?

i purchased gardenias and the leaves are

turning yellow . i feel like they are dying.

why? and what should i do?
Why are my gardenias leaves turning yellow?
Gardenia needs a fast draining soil but one that retains moisture: if the soil is sandy it needs a large ammount of organic matter from a good soil conditioner. We used to recommend peat, but from an ecological perspective this is no longer advisable because peat bogs are being overmined and are not being allowed to regenerate. Use compost or ground bark as an organic matter amendment to the soil. The leaves yellowing could be due to salt build-up from excess watering with high salt content water. Check with knowledgable gardeners in your area as to the water quality there. If the soil is poorly drained and water-logged, the plant needs to be located in an area of higher elevation relative to the area where it now resides. Using mulch to help keep the soil moist and add to the organic matter is a good gardening practice and allows you to water less often, which is particularly important if your water is high in salt content.



Leaf yellowing is sometimes a sign of nitrogen deficiencey, but be careful not to overfertilize, because this can damage the plant and always is a risk to the environment by run-off into groundwaters. During the growing season you could lightly fertilize monthly with a balanced acid based plant fertilizer or fish emulsion.
Reply:Gardenias need a lot of iron, and a very acidic soil If the leaves are yellowing, but the veins are staying greener, this is almost certainly the cause. I have used Miracid (from the same people that produce Miracle-Gro), and it works very well for gardenias, azaleas, and other acid-loving plants.



If the leaves get brown or black, then it's not getting enough humidity; it's hard to give a gardenia too MUCH humidity, as far as I've ever been able to tell.



Good luck!