Sorry I don't know about the plum tree, Mr. Happy.

I'd like to pass on the word about a wonderful plant I found a few years ago. It is called Siberian dianthus, and I ordered seeds from Park Seed Co in South Carolina.

Despite being called "Siberian" it thrives in our hot summers. (Summer can be hot and dry or hot and humid here.) It is a pereniel (sp) and forms mats with spiky foliage and purple-blue blossoms. It is very tough, and I just love it.

Info is here, but the color in the photo is a little too turquoise, at least on my inexpensive monitor.

http://www.parkseed.com/webapp/wcs/stores/servlet/StoreCatalogDisplay?storeId=10101&catalogId=10101&langId=-1&mainPage=prod2working&ItemId=0745&scChannel=Top%20Ten%20Seeds