magic fungus?

When I first dug up one of my raised garden beds I noticed a strange white fungus-looking thing growing through the dirt.  I took some to a garden centre and they thought it was mycchoriza.  What's that you ask?  It's a type of fungus that lives in the dirt and forms a symbiotic relationship with lots of different kinds of plants.  They tend to make the plants healthier and help them absorb more nutrients.  The white stuff in this photo is mycchoriza.  Here's a close-up.

I didn't think much of it at the time, I was more happy that it wasn't a "bad" fungus.  I planted my rhododendrons in the two raised beds and forgot all about the fungus.

A little while ago someone brought mycchoriza to my attention again with an article about how they can help tomatoes.  I had another look at my rhododendrons which are starting to put out new growth after getting horribly sun-burned.  This is what they look like in the bed that has the fungus in it; most of the fungus is on the left-hand side.  Look at all of that new growth!

Now look at the raised bed on the right.  It doesn't have any mycchoriza in it, from what I can find.  There is new growth coming in on them but they're still just tiny buds at this stage.

Now I don't know for sure if it's the fungus that's making the difference.  Food and water has been the same across the two beds but sunlight has not.  The bed on the right gets a lot more shade, especially on the biggest rhodie (which was bigger when I first planted it).  Which means those two rhodies should have gotten less sunburned, but maybe they're growing back more slowly because they're more shaded.  But on the other hand, with rhodies I would almost think the ones in the shade would be "happier" as rhodies don't like full sun.

In any case, the fungus certainly isn't doing any harm and may be doing a lot of good.  So today in between rain showers I dug up a bucket full of dirt with fungus in it and spread the love.  Most went to the other rhodie bed in hopes that it will take root and help those two out.  But I put some under my poor little Japanese maple too, and some more in the veggie bed with the pumpkin.  I hope it catches on!

Whilst I was at it I also went through the laborious task of taking care of the rhodies.  The soil in those beds is very sandy and I planted some of them too high in the dirt.  Oh, and I made the mulch way too thick.  So I scraped the mulch out of one half of each bed and dug in a custom mix:

Coir: shreded cocoanut husks, good for retaining water and nice and acidic which rhodies love.
Clay soil: from my dirt pile.  I still have a lot of dirt left over, and as I mentioned it was a mix including clay soil.  I found the part of the pile with the thicker dirt in it to help the rhodies retain water.  I even bought sulpher to mix in to lower the pH.
Clay kitty litter: yes, apparently one of the best ways to improve sandy soil is to mix in kitty litter (not used, please).  Think of it as custom-made pellets of clay soil.
Oscmocote: for some long-term nutrients.

After digging all that in I spread the mulch back over, peeled it off the other half, and had to do it all over again.  Oy my back hurts.  And I almost finished before another rain shower sent me packing back inside.  Tomorrow they'll get a drink of powerfeed and seasol to round out the pampering and get that new growth powering along.  I really do pamper those rhodies too much.