Removing some of the clay to accomplish the depth would only creat a sump or 'bathtub' as you say. The best way would be to add another six inches or so of additional top soil to the area you want to put them. Lilies generally perform much better in the ground than in pots.

Good idea. I tried mounding the soil over a clump of daffodils planted last fall. The soil will not stay--mulched with bark, then pine straw, then straw over a layer of leaves. The bulbs were half exposed last time I covered them and put a ring of rocks around. This seems to be holding better and the tips are now up 3/4" so that helps too.

The lilies will not be dormant all summer during our often drenching rains like the daffs, so will try to raise the soil level by several inches and corral with rocks.

Do you think extra sand and bark chips in the backfill would be any help, or just sand? Thanks again, Michel

Well, you don't want too much sand or it won't hold the nutrients. I usually recommend filling with top soil thats common to your area. But in Zone 7 Alabama, and as an example, Jefferson county (Birmingham area) and the six counties that border Jefferson, soil types can vary a lot-even from one neighborhood to another. Lilies (Lilium) prefer a sandy silt clay loamy soil, quite rich in organic matter. You can test your soil suitability by saturating a sample with water, then rolling it into a marble size ball in the palm of your hand. If you have too much sand it will be difficult to roll into a ball or if it does, it will fall apart right away and your hands will feel gritty. If you have too much clay, the ball will form easily and will not fall apart when pressed with your index finger-and your hands may feel somewhat greasey. A good mix would be one that rolls into a ball, but crumbles easy when pressed with your index finger. If you can do that, then your own backyard soil is good enough for filling. Lilies aren't too fussy about soil and don't require a lot of fertilizer either. Generally, a lower nitrogen type-something like 5-10-10 applied in spring and again after blooming is all that's required. Adding leaf compost as a mulch is a good ideal. And providing a good layer of large bark chips to the surface as you mention will help keep the roots cool-which they like. Also, Oriental types like a slightly acid soil pH of 6.5 or so. If you live farther northwest of Birmingham, you get into more of a limestone type soils which run higher pH.

Just as a note--if you're still not comfortable with using your soil to raise your level, then as a suggestion only (and I don't mean to promote anybody here) there is a company based out of NW Georgia called River Run that bags top soil common to your region. It would be availiable from a big box store in your area called Lowes. A potting soil/garden soil version is best and one that I have personal experience with in my lily gardens. And, it's 'dirt cheap'. Again, I want to stess, I'm not promoting anybody here--just trying to make things maybe a little easier.

Edit Added: After reading 'your page' I NOW realize you ARE in Jefferson County that I used in my example. Wow! Yes, I do know about your 'heavy downpours'!!!

This post was edited by interspecific on Thu, Dec 6, 12 at 8:45

Hi Inspec
Thanks for all the good info. Maybe I'm obsessing over this soil type too much,but trying to garden on New Hope mtn (just south of Bham in Shelby Co) has been a real challenge--just rock and clay! Boy can I give them the silt, clay with noooo problem, and my homemade compost will provide a good organic mix.

You must have lived somehere around here. You are so knowlegable about the area's soil types.

Thanks again for taking the time to give me so much good advice. Mm

I have many, many relatives in the region (esp. Columbus, GA) So, over the last 40 years have been seeking out a place to retire and still be able to carry on my hobby of hybridizing Lilium--somewhere along 280, rural Chelsea to rural Childersburg.

On the subject of clay--don't forget, you only want clay to act as a binder--just enough to hold the soil together--20% or so. Also, when you raise your level, go a couple inches higher than what you want in the end because your mix will settle considerably over the next couple of years. And the mulch with large chunks of bark to prevent washing and also to keep the roots cool.