The soil requirement for these beauties is acidic. On the Ph scale that means around 5.5 or lower; if the soil is sweeter they will die. The reason is best explained like this.
Look at the Ph levels as if they were a screen filter; the higher the Ph (or sweeter the soil) the bigger the openings in the screen. The lower the number (or acidic the soil) the smaller the openings are. Rhododenrons need the smaller opening screen the acid soils provide.
Big holes, small holes???? So what!
Nutrients come in different absorbable sizes; bone meal with its calcium foundation is a bigger compound than the iron micro compounds. Acidic soils keep the Rhodo killing bonemeal compounds out, while letting the micro compounds in. Which brings up this important bit of info; when buying fertilizer for them buy only Rhododendron/Azalea fertilizer, it does not have a bonemeal base like the others.
If you are wondering if your soil is right for Rhodos you can have it tested at most garden centers by taking in a sample of your dirt. Make sure you go down deep enough to where the roots will be.
One other tell tale sign for good Rhododenronable soil is if your Blue Hydrangea flower is indeed blue and not pink; a sign of good acidic soil.
If you have any questions feel free to e-mail me at NiemeyerLandscaping@Gmail.com or post a comment on this Blog. And like us on Facebook at Niemeyer Landscaping. For more Landscape and garden info and pictures on the subject check us out at www.NiemeyerLandscaping.com