Part VIII - Living Walls - Rhododendrons & Azaleas: A couple of Rhododendron questions

» blazeburns - A couple of Rhododendron questions

I've had a difficult time maintaining healthy Rhododendrons since I've moved to northern Virginia. I think the cheif cause is awful, nearly all clay soil, in conjunction with difficult weather conditions the last three years (two droughts and a very rainy year this year). Many of the remaining plants are exceptionally large and I don't think it is feasible to remove them to raise them or relocate them to a prepared area. Are there any steps I can take to amend the soil?

Also, I lost one of the very large plants this year (I think due to root rot) and received advise from the garden center that I should remove the dead plant's roots or the fungus in the ground would spread and also taint the earth so that no Rhodie or Azalea could ever be planted there again. I made an effort to remove the dead roots, but it appears the task may be extremely difficult due to the size of the roots and proximity to other healthy plants. Is it absolutely essential to do this? I will do it if it is, but it sure would be nice if I could avoid it.

Thanks in advance for any help you can give.

-- posted by blazeburns