In most parts of the country, September marks the time when the temperatures begin to drop. The days are still warm, but no longer hot, and nights are chilly. Fall colors begin to emerge and compete with flowers for attention in the garden. This is the time many cool weather annuals and perennials are available. These flowers will bloom in your garden until the first winter frost as you enjoy the last blooms of summer blooming plants.
Although roses are generally considered a summer blooming flower, most of them are still sending out flower buds in September. In hot climates, the roses may recover from high summer temperatures by a show comparable to the first spring flowers. In cooler climates, the flowers may be smaller and less frequent, but no less beautiful. Don’t feed your roses in September as this will cause the plant to grow new leaves right before it should go dormant.
Reaching only 8 or 9 inches tall, pansies are an adaptable plant, preferring the cooler weather of fall and spring to the heat of summer. Pansies have large flowers with five petals and bloom in a wide range of colors such as red, pink, bronze and even black. Pansies grow in full to partial sun and well-drained soil. Yellow or blue pansies have the strongest fragrance of all the pansy flowers, according to Texas A & M University. In mild climates, such as he south and far west, the pansy will bloom from September throughout the winter.
Dahlias boast one of the most diverse flowers of the plant kingdom. Flower sizes range from a half-inch to over 12 inches in diameter. Dahlias are a herbaceous perennial that grow in full sun or filtered shade in moist, well drained soil. The flowers usually appear in July, according to the University of Minnesota, and last into September.
A cool-weather annual, snapdragons bloom in every color imaginable--from pastel pink and white to vivid reds and purples. Snapdragons prefer well-draining slightly moist soil and full sun. They can tolerate light frosts, according to Planet Natural. Multiple flowers bloom on tall stalks reaching between 12 inches and 3 feet tall, depending on the cultivar. Under ideal situations, snapdragons can self seed.