Calendula, or pot's marigold is a perennial that sow itself by seeds. It blooms until the hard frost hit in zone 5a. It attracts beneficial insects like lacewings.
My garden in alkaline clay, pH 7.7, with 38 to 40" annual rain, cool and wet spring/fall, hot summer, and -20 degrees below zero in winter, 32" snow, and strong wind.
Angel face makes good cut flower, lasts 4 days. It's heat-tolerant, and great scent. I deepened its purple color by watering with less than 1 tablespoon molasses/soluble gypsum in 2 gallons of my tap water at pH 8.
Yellow sun-drops flowers love my alkaline clay, spread like wildfire (I have to kill them). Peonies, yarrow, and black-eyed susan are also invasive in my alkaline clay.
Annie blooms heavily in full sun, but for root growth, it's best in partial shade initially. Her leaves are always healthy. Survived my zone 5a winter. This rose needs both gypsum (calcium sulfate) to prevent balling in the rain, plus potassium (sulfate of potash) for best blooms.
