Growing perennial plants in hanging baskets creates its own challenges because the hanging baskets are exposed to harsh temperatures and must be watered during the winter, even while they are dormant. However, perennials come back every year and don't need to be replaced in the spring. Most perennials that grow up to 12 inches high and have a trailing habit are suitable to plant in a perennial hanging basket.
Scented geraniums produce a wonderful fragrance when the leaves are crushed. Some scented geraniums have a citrus smell and some smell like a rose. The plants have small blooms, but the fuzzy leaves trail over the side of the hanging basket over the growing season. The plants will return from the roots every year, but will need to be divided every other year if the roots become too crowded in the perennial hanging basket.
Trailing rosemary is a tough herb that can withstand full sun or part shade. It has a wonderful smell when the leaves are crushed and produces delicate blue flowers in the spring. It is disease and insect resistant. If you locate the plant outside the kitchen door, you can break off pieces of rosemary to enhance the flavor of fish, chicken and rice dishes.
Asparagus fern is a drought-tolerant fern that is suitable for a full sun or part sun location. In full sun it needs daily watering. The hard green leaves and branches can be cut and used in long-lasting flower arrangements. It will freeze down in the winter if left outside, but will get really large if protected and allowed to grow throughout the winter in a protected location. The roots become very dense inside the perennial hanging basket making the perennial hanging basket heavy over time so additional support may be necessary.
Wedelia is slow to get established but after the first season the trailing green ivy-like growth will cascade over the side of the perennial hanging basket and display numerous yellow daisy-like flowers. The wedelia thrives with minimal care but for the best show, fertilize with a water soluble fertilizer suitable for potted plants and locate in part sun.
Several varieties of trailing lantana are suitable for planting in perennial hanging baskets. "New Gold" grows quickly and produces yellow blooms several times during the growing season. There is also a purple and white variety of trailing lantana. Trailing lantana plants get very large but the old wood can be cut back to shape before the plants emerge from the roots and stems in the spring.