I can tell you there is no point in planting them in poor draining clay soils. Recently dug some up in this type soil. They looked bad, & were planted about 8 yrs ago. I could see the shape of the container in their roots. Roots had not grown a bit! A friend went to England & told me they grow like trees over there. He also seen some elsewhere growing nicely in dry rocky conditions. This leads me to believe that these plants can survive better in dry, well draining conditions than they can in wet muck with it's lack of oxygen.

The soil was not amended at all where I work when the plants were installed & I have removed 75% of them. Several 'Roseum Elegans" put on such a great flowering that I have kept them. Planted Feather reed grass 'Karl Foerster' below/in front of them. After they bloom the grasses seed heads emerge and hide the foliage of the Rhodo's. Use Ironite, acidify, & wilt proof for winter protection.

I am not an expert on this. Others can give you more info than I can. I look forward to reading future reply's to your question as I need to learn more myself. Later.

Hmmm. Actually, I was growing in similar clay in Connecticut. Same stuff, different color. What I was concerned about was the acidity. Other than Miracid, what do you do to increase the acidity of the soil? How about blueberries? They need acid soil too...do they croak here?

I add pine soil conditioner and mini pine nuggets to the soil. As it breaks down it helps acidify. It also helps with drainage & loosening up the clay. There is also a product by Acre, it is a slow release granule, which increases acidity. You will have to call around to find it. Home Depot etc. will not have it. Mulching with pine bark nuggets or pine straw would also help.

Cannot help you with the blueberries.

I live in the Oxford area, and have two evergreen Girard azaleas in front of my porch. Part sun. Soil is heavy and contains lots of clay, but they seem to be doing OK -- they are about 8 years old now. A bit leggy, but healthy. I didn't get as many blooms this year because I forgot to deadhead last year, so there were tons of seeds (I have plenty to share if anyone wants any!)

I did use Miracid for the first time late this spring after flowering, and will probably use it again in a week or so. Our soil is pretty acidic already, though. I also mulch every year with shredded bark and after 8 years of mulch I don't get many weeds :).

I did dig the holes very deep for these babies to break up the soil when I planted them, and perhaps that has helped their drainage. Plus, we have earthworms galore here.

In addition to amending your soil with pine bark (as suggested above) and compost, you might add some vermiculite which helps improve drainage. At the very bottom of the hole, you might put several layers of small rocks under the rest of the soil as that might help drainage as well.

:-) Mel