Known for their intensely fragrant flowers, sweet peas (lathyrus) have been cultivated for more than 300 years. Their flowers appear in many different shades from red and pink to yellow to white, plus combinations of colors. A stem bears from one to seven flowers, each about two inches (51 millimeters) wide.
Sweet peas can grow to be 4 to 6 feet (1.2 to 1.8 meters) tall, although some bush varieties aren't quite as tall. If your area usually has a mild winter, sweet peas can be planted in the fall; otherwise plant them in early spring. You'll be able to enjoy the flowers from spring through summer, although they don't really care for intense summer heat.
A gardener's tip: Some varieties aren't fragrant at all, so be sure to read the description of the type you're purchasing.