Being very new to Rhodies I'm wondering what color new leaf growth should be? The older leaves are dark green but the new leaves are pale yellow with dark veins. I guess I want to make sure that it's not in need of something.
Needs iron. You could add some chelated iron, but make sure to check your soil pH too, if your soil is alkaline then even if there's iron in the soil the plant can't take it up. So if your soil is alkaline, I'd fix that first and see if it greens up on its own, then add the chelated iron if it doesn't.
ecrane I tested the soil this week and it appears that the soil is 'slightly acidic' at 6.5 ? Now I've read different numbers in different places. I've read they should be between 4.0 and 6.0. What's the number I that I should be striving for and what's the best way to get there?
Honestly I think it will probably be OK at 6.5--if you're over 7 then I would try to amend the soil, but amending is really a pain and I think (not positive though) that they should be able to absorb iron at pH 6.5. I would at least give it a try adding some iron, then if some time goes by and you're not seeing an improvement then go back and try to amend to lower the pH.
All the above messages are valuable anwers to your question but very often new leaves are much lighter when they first come out than when they are mature. Why not wait a while untile the leaves are mature before you start any other corrections? I have damaged or even killed more rhododendrons by over care ( over fertilization etc.) than i ever helped. They are plants which once they are established need little more than some water in a drought. They get a lot of their necessary nutrition from the mulch which should cover them.
New leaves often are a paler color, but the leaves in the picture in the first post definitely look chlorotic, they have the typical pattern of green veins surrounded by the rest of the leaf being yellower. This does indicate a need for iron, I don't think it's just a case of the new leaves looking a little different color and they'll eventually green up on their own
I have a similar concern about two new plants that I added to my garden earlier this spring. Both were blooming when I planted them. Both have new growth that is lighter and the lnew eaves have that veined pattern you described.
Will I solve this problem with an application of brand name (Miracle Grow) azalea/rhodendron food? I fed them recently with plain old (general) Miracle Grow--the other (more mature) leaves look very healthy, but the new growth doesn't look so hot.
If you fed them recently you probably don't want to feed them again right away, too much fertilizer will burn the plants. I would check your soil pH, and if it's at least slightly on the acidic side I would see if you can find a product that just has chelated iron in it (not a bunch of fertilizer too) and add that. If your soil pH is high, then you might want to adjust it down a bit first, then if the leaves don't green up in a few weeks then add the iron (if your soil pH is too high, the plant can't take up the iron even if there's enough in the soil)