Hello. Yesterday, I completed the last of my flower planting for the late spring/early summer (I know, its almost August). I have a new flowerbed on a hillside and I was able to rototill half of it with my neighbor's 30 year old tiller. Unfortunately, I ran out the old gas and when I filled it with fresh, we were never able to get it running any more.

That left the challenging, tree-root ridden, rock hard clay side to be worked by hand. I wanted to get something in there and so I sharpened my Razorback shovel edge and also put a new hardwood handle on it.

I have been able to remove quite a few thick roots from a nearby maple tree and I have dug small areas pretty deep.

Here's my question: when I dig a deep hole in the clay, is it OK to fill the bottom with my own homemade compost/mulch about 2/3's up then just top it with a mound of the cultivated clay on top? I don't have the time or the muscles to completely incorporate the compost into the clay, but I do go back with the spade later, once the plant starts growing and dig around it and mix in more compost, then top-dress with even more.

I'm planting Pineapple Sage, Lambsear, Munstead Lavender and Delphinium.

The sun is partial with full sun maybe only 2 hours a day or a little more.

One of the Lavenders is almost completely dead already, but the other 3 look good, the delphinium all look good (surprisingly) and the Pineapple sage looks like it could survive anything.

So back to the question: Does anyone cheat and just fill a deep hole almost entirely with fluffy compost and cover with top with the indiginous clay?

Thanks from a slightly tired rookie.