Window boxes "draw your eye through the window to the outside," Gillingham-Ryan says. So put them right outside your window, either in the windows or on a deck or patio. It visually extends your room out to the window boxes.
For a little extra verve, plant herbs, which are typically green and low-maintenance, he says. Or you can plant flowers for color.
Tip for success: Window boxes can get dry quickly. So if you often go away for the weekends, opt for something that doesn't need regular watering -- typically something green and hardy, rather than colorful and delicate, he says.
"Be ambitious, but be realistic," Gillingham-Ryan says. "If you overshoot and get disappointed, you're likely to give up."
Inside the home, flowers and potted plants add color, joy and warmth. The price is a barrier for a lot of people. Bromstad's pro trick is to buy from a flower wholesaler. "You don't have to be in the trade," he says. You just have to be willing to pay cash.