I also garden in heavy clay and have found (in addition to amendments like you have added) raising the bed at least a few inches greatly benefited the lilies. The problem is that your organic additions will last the season then you are back to the clay problem. I grow a lot of lilies and I can no longer work the compost in without risking slicing into a bulb so now I just top dress with compost each spring and the lilies love it. I lost many lilies to rot before I raised my beds a little. Before planting, I also worked in some river loam to help with drainage. It persists on a more permanent basis. Hope this helps.

Thanks for the tip.. I think I will raise the bed too. I have the conditioner + compost mixture to a depth of 15 inches and have loosened the clay another 3-4 inches.

Sounds like you have a good plan for your lilies. Let us all know how it works out for you!

Did you mix the soil conditioner and compost into the soil, or are you using the two all by themselves? If you're using just those two and no soil, that's awfully rich. Lilies like rich soil, but that's more like growing in straight compost, which is a pretty good recipe for various rots.

Jeanne

You have an excellent plan, carygardener -- especially loosening the clay soil another 3-4." We are commercial growers of cutflowers, and experience all types of soil in our flower beds. Conditioning and composting is going to be of great benefit to your soil. A soil with is full of organic matter, and full of organisms, will have a high rate of respiration. This is the soil in which plants flourish. Organic matter serves as the principal fuel for soil respiration. Top dressing in the manner pardalinum suggested after no longer being able to work the soil will conserve moisture and suppress weeds while also adding nutrients.