Fall has arrived and our garden plants are putting on a great show as they prepare for the end of the growing season. Some plants that show us the best color this time of year are the aster and chrysanthemum.
Asters are a fall garden staple and are in the Asteraceae family, one of the largest families of garden plants. According to the Sunset garden book there are over 600 species of true asters. A few plants in the asteraceae family that might surprise you are sagebrush, ragweed, sunflowers, thistles and cocklebur.
Fall asters range from alpine kinds that are 6 inches tall to plants billowing over 6 feet tall. Flowers come in white, blue, red, pink, purple, and lavender, most with yellow centers. Asters will grow in almost any garden soil but, like most plants they prefer a fertile soil that is well drained. Asters need full sun to bloom their best. They really are trouble free except for powdery mildew, which you might find at the end of the growing season. Cut back the asters by ½ to 1/3 in early summer so they will be shorter and bushier. Asters require regular water to look their best.
Garden mums have been around for nearly 2500 years, the Chinese being the first to bring them into the garden. Now there are over 5000 named varieties so there’s little doubt you can find one that you like.
Chrysanthemums require full sun, and like asters, need a regular amount of water. Pinch back several times in early summer to encourage more blossoms. Begin when the plants are about 6 inches tall and continue until about the 4th of July. When the shorter days of fall arrive that’s the signal for the plant to begin its show and a compact plant that is full of blooms is your reward for regular early pinching. New cultivars have been developed that are naturally more compact and better bloomers. .
I’ve had many people ask me if the chrysanthemums that they buy in the grocery store can be planted outside. The answer is yes. Florist mums have been forced to bloom out of season and once planted outside will revert to their natural bloom cycle. The bloom time may be shorter than a mum bred for the garden but they will certainly grow.
Divide overgrown plants in spring. Fertilize with a bloom booster early in the season ending fertilizer applications a few weeks before bloom.
If your mums aren’t blooming consider several things. Is the plant overgrown or being crowded by other plants? Being shallow rooted, they aren’t very good at competing for nutrients and water. Consider light. Is it getting enough sun? Hot summer days can also delay bloom.
Chrysanthemums and asters are some of the most common and favorite flowers that give us fall garden color. With all choices in color and shape, every garden should hold at least one of these old time favorites.