flora_uk - I think that's it. The pictures I've seen online are a good match, and I vaguely remember having a plant called "Alyssum". esh_ga - I was just worried about putting large photos directly here because I've heard it causes problems for people with slower connections.

In my yellow and blue border, the very best sources of all-summer yellow color are from shrubs: Spirea Thunbergii "Ogon" (really needs a bit of afternoon sun in our heat), Duranta "Cuban Gold", and Berberis thunbergii "Aurea" (thorny, but low, gorgeous and unstoppable in our hot sun). These yellow leaved shrubs are some of the bones of the border. I also use Tanacetum Isla Gold (again, golden foliage), especially near the front edge. In early summer I use lots of yellow daylilies. I am very particular about the shades I choose. Cool yellows and warm yellows sometimes clash to my eye. Rudbeckia "Herbstonne" (lovely foliage is a bonus), Helianthus "Lowdown" (tall but never flops), and "Carefree Sunshine" Rose add later blooms than the daylilies. I also have alot of Zephyranthes candida along the front edge, which is a white rainlily that has a prominent yellow eye. I added zephyranthes reginae to the border this year, and the few blooms I got were a lovely cool yellow. It's very hard to beat rainlilies from July to late fall around here. In addition, I use a few yellow blooming annuals in that border: Yellowbird Cosmos and yellow marigolds (again, watch the shade). In combination with several blue salvias, stokesias, Rozanne geranium, etc. it is a very satisfying bed.

No, I really think it is one of the Potentillas but I wasn't sure which. We have 85 species native/naturalized in North America:http://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=POTEN&display=31 FataMorgana

Wonder which Jethro Tull it was named for. One of the great founding fathers of modern agriculture, or the rock band from the 60s? I like the Jethro Clampett cultivar myself.