Roses are classic perennials found in many gardens, and I couldn't resist adding them to the balcony. The ones I got are mini roses, which are perfect given the limited space. The mini roses are currently featured sale items at Whole Foods; at least in NYC. They're available in different colors like red, pink, yellow, white, and mauve.
The roses add a nice floral touch to the balcony, which is currently green with herbs, tomato plants, and a few trees. I've placed them around the balcony, sitting in planters with other growing plants or trees. Placing the potted roses in with potted plants helps to free up floor area clear for moving around (and eventually a bistro set for two), and it makes watering the plants a bit more efficient.
A tip for selecting an adorable little rose plant is to look for a plant with healthy leaves (no holes or dried brown foliage). It's okay to select a plant with some opened blossoms however choosing a plant where there are some buds that are about to bloom and emerging buds will be more rewarding in terms of display.