We’ve honed enviable gardening skills over the past few summers. Our tomato plants stretch to the sky. Our strawberry plants could feed a brigade. We pickle banana peppers and cucumbers. Herbs? We grow more than you’ve got names for. Until this summer, though, we wasted not a thought on flowers. We subscribed to the moto: “If you can’t eat it, who needs it?” How bullheaded of us. Our eyes have opened. We now live in a world—or at least a backyard—of beauty and serenity. Newbies to flower gardening, we’re learning. We’ve experimented with dahlias, daylilies, cone flowers, mums, morning glories, etc. Our favorite by far: zinnias. We couldn’t imagine a plant easier to grow than a zinnia. And, the reward for your minimal effort is broad, vibrant flowers that bloom heavily all summer. Pat yourself on the back; you've earned...