On a sunny Saturday morning in Santa Cruz, California, a flower stall lures shoppers out of the lively bookstores and cafes that line Pacific Avenue. The tiny shop, called Bonny Doon Garden Company, sits smack dab in the middle of the sidewalk, making it impossible to miss. Buckets of colorful tulips, peonies, and roses sit underneath market umbrellas, and customers are free to pull out the stems they like and arrange their own bouquets. Owner Teresa Sabankaya stands at a workbench next to the stall making an arrangement that she calls “Citrus Punch.” It’s a cosmopolitan bouquet that includes organic orange roses from Ecuador, red and yellow gerbera daisies bred in the Netherlands and grown in central California, and lime-green euphorbia from her own garden, all perched atop a tall, skinny glass vase filled with lemons and limes. “Citrus Punch” isn’t cheap; it costs $125, the going rate for an upscale, designer bouquet in the Bay Area. But Sabankaya works hard to make sure her customers understand what they’re getting for their money. “Whenever people tell me that they think flowers are too expensive, I remind them that a lot went into that flower,” she says. “When you think about where they’ve been, and everything that’s happened to them, they’re really quite a bargain.”

Consider the roses, a bright orange variety called ‘Impulse.’ They were grown on a farm just outside Quito, Ecuador, that is known for its environmental and socially responsible practices. The heads of the Ecuadorian roses are twice as large as anything Sabankaya can get in California, the colors are always brilliant, and the varieties she favors are bred to hold their lush, full shape in the vase. ‘Impulse’ is a marvel of modern rose breeding. It was bred not just for beauty but for its ability...