Question
Dear Mr. Crowder,
Something is wrong with the soil in the garden next to my house. Recently a beautiful Red Flame bush died, now a large rhododendron has curling leaves.  Gladiolus, hollyhocks, and a lovely delphinium all died.  The site gets plenty of water, has good drainage and supported plants well until about two years ago. Any ideas?  Is there a soil testing kit I should buy?

Answer
Hi Lea, If it were nutritional, I would expect some plants to suffer but others appear unaffected.  When wide varieties of plants die, I would expect it to be fungal/drainage related, herbicide damage or vole/shrew/field mouse damage.
Take a couple of your dead or dying plants, roots and all, with a soil sample to your local nurseryman.  He'll be familiar with soil diseases in your area, he might test your soil for you, and he can tell much by the texture of your soil.
Look for evidence of rodents. Small holes about the size of a dime and gnaw marks at the base of plants.  If you feed the birds, you probably have voles or field mice around.
I suspect it's fungal.  A good fungicide and improving the tilth and drainage of the bed will probably fix it.  You may need to use plants less susceptible to root diseases and your nurseryman can help you with that.  Jim