You might also try at the organic rose forum They have a lot of good info on soil.

Your soil test results should tell you what you need.

Part of why the soil test results matter is that the weather can affect the rose's uptake of minerals in the soil, and adding more wouldn't help then (and might create other problems). For instance, a lot of rain and waterlogged soil can interfere with uptake of minerals like magnesium or iron. I can't recall at a glance what the leaves look like for poor magnesium vs. iron uptake, but they both involve yellowing and need different solutions, some of which is to wait for the weather to change.

If you do find that this is a chronic problem and you need to add something, our clay soils maintain nutrients longer than sandy soil would. For me, I add soil sulfur to increase the pH of the soil for things like blueberries and azaleas. It usually lasts 3-4 years and it's possible to overdo it for some roses, though most like soil a little more acidic than base. If you add iron, I think it's best to add chelated iron that the plants can take up more easily. I use Ironite and it seems to help as a general fertilizer in spring.

I don't think it would hurt to add a little Ironite or Miracid as a fertilizer and see what results if the effects persist after a week or two, but don't add that on to other fertilizer treatments. Just my two cents - most of rose gardening is being patient with the roses and helping them shake off things that are affecting them when possible.

Cynthia

Thank you, Cynthia. I tested the soil before planting but don't remember the number. I'll test it again. I'm a little concerned that the clay doesn't drain well and is keeping the roots too wet. I see that I need to get some neem oil, too, as I've got some holes in the leaves from little things munching on them I assume. I like your paradigm of helping the Rose shake things off. Right now I'm approaching it more like a helicopter parent who can't bear to see her baby skin her knee (which isn't how I parent my human children!)

Hi Robin -

Good analogy about the helicopter parent, and we tend to be that way till we figure out what roses can handle (they're tough). A much easier (and more effective) solution for your holes in the leaves is just to spray a steady stream of water at the rose as well as under the leaves, to knock off the rose slug caterpillars. Neem oil can cause some frying of the leaves if you spray when the weather is too hot, whereas water never hurts - except where there are drainage problems as you state. You can always add organic material like leaves or compost to topdress your soil, and over time that can help improve the drainage of clay soil. I like cotton burr compost since it's light and fluffy and gets worked into the soil by earthworms easily. I like lazy.

Cynthia