The salts in the manure could be a problem with these subjects, the unnatural equal high proportions of primary nutrients in the 20-20-20 are also likely to produce difficulty. Then there is the question of whether or not every trace element in the product you have, if any of them, needs to be supplemented.

You really should sample your soil and have it analyzed before laying on a significant amount of nutrients. Unlike annual field crops like corn trees and shrubs cannot readily make good use of high does of nutrients. Rhododendrons and azaleas are heathland and forest plants built for leached soils in high precipitation climates, some such as our native Labrador tea (Rhododendron groenlandicum) even occur in peat bogs. You can discolor or burn these up quite nicely with strong fertilizers, even kill them.

Yes, avoid the steer manure at all costs with rhodies.

What are 'fritted elements'?

I use a commercial organic rhodie food on mine, they're usually something like 4-8-4 or something like that. Less nitrogen, more phosphorus. They don't need much of either. 20-20-20 would be way too strong. Then I mulch them with leaf mold from the leaves I raked the previous fall. The fertilizer goes on the soil surface (don't scratch it in with rhodies, their roots are very shallow and very fine and they will not like you if you scratch up their roots), you water in the fertilizer, and then the mulch goes on top. Don't mix the fertilizer in with the mulch.

Their native habitat varies as garden rhodies come from all over the world, but in general they like lean, well-drained, woodland soils. That means low nutrients but a fair amount of leaf litter for mulch.

The receipe, which I give below, is highly recommended in the latest issue of "Gardenwise." However, the replies I've received from web fans is a bit confusing..... comments, please! (Here is the receipe)
10 kg mushroom manure
10 kg Bark mulch
250 ml rhodo fertiliser (not specified)
60 ml chelated iron or fritted elements.
Mix together and spread l inch layer out to drip line.
I'd be interested to hear what you all have to say!

Well, again, without knowing the mineral content of your soil it's impossible to know how well-targeted this would be. Soils vary! It's not true that because it's the same kind of plant (rhododendron, rose, fuchsia, whatever) that you can put the same combination of nutrients on all soils everywhere and be assured of good results.

I usually stay away from the mushroom compost for acid loving plants because of the lime it contains, unless I'm spading it into a new area and adding only a little.

As for the steer manure and rhodys, I've top dressed for several seasons with an inexpensive blend (Home Depot) when I don't have enough of my own compost - it's bagged aged steer manure (and I know well aged because it's odor free), aged bark/wood chips. No negative effects at all - not even around seedlings.

A local rhodie expert here told us to use Osmocote. I have wonderful flowers on mine.

well, isn't that confusing! Guess I'll go with trial and error (and not too much error, I hope). Thanks for all the comments.... isn't it amazing that, in spite of the conflicts of opinion, the rhodies keep growing!

If you sample your soil and have it analyzed you will have an idea what you are dealing with. That's the point of doing it, you aren't left on your own. Same as going to doctors to find out about your body.

My biggest concern with this recipe is mixing the fertilizer with the mulch. Fertilizer has to be in contact with the soil to work. Some nitrogen will wash through the mulch and into the soil, but the other elements are much less mobile. The elements in fertilizer have to be dissolved in water and in direct contact with a root hair in order to be taken up by the plant. Won't happen when the fertilizer's in the mulch layer.

Mushroom compost usually is made from steer manure, but the manure is so thoroughly aged and leached and worked over by the mushrooms by the time they sell it to you, that I use it all over the garden with no qualms. Steer manure itself I never use on rhodies or in clay soil, due to the salt content.

Yes, the rhodies grow despite differing opinions on what they need! Then sometimes they up and die no matter what we do. Humbling, and rightfully so.

I planted about 30 rhodies in Dec05 that were in bad shape. Been using Lilly Miller Rhododendron, Evergreen & Azalea Food fertilizer on them Feb 1, May 1, and August 1 since then until now. They have really greened up and have gorgeous generous blooms (Lee's Dark Purple). They are growing slowly.

My yard helper injured his foot so we're behind a month. It will probably be next Sunday I'll fertilize absolutely every centimeter of this yard with the above. Instead of scraping it into the dirt (don't want to disturb roots and everything's covered with some groundcover or other) I add a very thin layer of 4-way blend dirt over the fertilizer.

After that the worm bin will be producing enough to wormcast every tree bush and plant each year. Over 300 trees so lots of leaves in fall that sit in a compost pile and make those worms very happy and multiplying along with free horse manure and kitchen scraps all added to the bin as room permits.

Have read that worm castings are nature's very best fertilizer so that's what we're aiming for. The trees we've already wormcasted are extremely healthy and vigorous growers. The difference is astounding.

Happy that after next week switching to all wormcasting totally organic rich natural micronutrient plant bliss.

All the guano from the birds is probably also helping the plants. That's literally tons of black sunflower seeds, millet, corn, peanuts etc liquiding back onto everything and washed in with rain and sprinklers in the summer.

I just use Apex commercial rhodie fertilizer, spring and fall and fine bark mulch once a year after bloom. It's just a simple formula that works very well for me. I just do it on all my rhodies/azaleas/pieris/cedrus/juniperus, etc all at the same time.

Virtually everything you see in this raised bed gets the same meal ;-)

Here is a link that might be useful: {{gwi:22102}}

Variations in soil conditions immediately limit applicability of experiences of others. What worked for someone else in same region could happen to be just exactly what you needed to do, or not very much. There can be fairly radical differences in soils right on the same site. If your soil is nitrogen deficient (by far the most prevalent deficiency here and often the only nutrient that needs to be supplemented to get optimum results from garden plants) that is what needs to be found out - and addressed. Down here I would seek help with this from WSU Cooperative Extension, their web site delves into soil testing fairly well.

OK... here's what I did. I applied the following mix to my rhodies (all youngish plants) in the front garden alone, so that I can test the results. My soil is extremely sandy and drains fast, I applied a mix of ........... 10 kg steer manure, 10 kg bark mulch, 1 handful 10-3-6 and about 2 tblsp. fritted trace elements. Tossed a few shovelfuls around each. I'll keep an eye on the results and report back. (Hope they don't turn up their toes and expire!)