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claire25_gw

English Roseum in full sun, fairly dry location...help!

claire25
13 years ago

Hi all,

I am a beginner gardener who is somewhat too inclined to experiment, as the following example demonstrates.

A few years ago I ripped out some ugly overgrown boxwoods that were planted around the foundation of my house in a south-facing full sun location. I replaced these with rhododendrons ('English Roseum'), basically to see if I could get them to live. They actually are doing better than you might expect, but I would really appreciate some advice to help improve as much as possible their condition.

Of course they bloom wonderfully on account of all the sun. However, I must be very careful with water in the summer...even with the fairly thick hardwood mulch I have around them they dry out almost immediately in the summer heat. The main problem, though, is that they turn a very sickly shade of green in the late winter; they seem to darken to a more normal shade after I fertilize with Hollytone in the spring. Basically I am unsure whether the color is 100% a nutrition issue, or whether (as seems more likely) sun stress is contributing, too. I haven't tested my soil yet and need to...anyway, its composition is EXTREMELY sandy and probably is deficient in easily-leached out minerals/elements. I also ought to know my soil pH and I don't...Lavender grows very well in the same area, though, and I know it likes an alkaline soil. That's not good for rhodos, I know. :(

My question is, would it help or hinder my rhodos if I started using a richer media as a mulch? I'm thinking composted cow manure, which I have a lot of. Is damage from overfeeding likely with rhodos? I have no experience with aluminum sulfate, but would topdressing with this help with the pH issue that I think is likely?

I also am wondering about using a foliar spray containing iron and/or magnesium to help them green up. Is that a good idea, do you think?

Please help me. I know I goofed by planting these here, but the funny thing is, they ALMOST do well in this location. If only the baby shade trees planted in the front yard in front of the rhodos would hurry up and grow...cart before the horse, I'm afraid.

Thanks

Claire

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