Some lilies, Orientals for example, thrive in a more acid soil mix.

If they are in the wrong soil they will die out over a couple of years, and since high quality bulbs are expensive it will disappoint and put off some less experienced gardeners, who will blame themselves.

I did a very basic tutorial on growing lilies. There are lots of factors and climates that can be detrimental to a lily surviving longevity. Adding non manure compost can add in reducing soil pH and can add years to lilies.

Thanks magnolialover, I agree, lilies may die of many causes, just trying to help reduce the toll. I have to say I knocked a few on the head with the soil ph problem before it dawned on me.