If I were a marketer instead of someone who feels better with dirt on my hands, I would ape somebody's commercial and hype asters as the other mum. In fact, asters share many of the attributes of mums, offer some advantages and have only one real shortcoming that I can think of.
A scan of any perennial catalog that includes plants other than the latest and the greatest will offer a lengthy list of asters. There are almost more varieties than we need. The list of the ones that I didn't like would fit on one hand with some fingers left over.
Check the perennial section at your favorite garden center or greenhouse. Most will offer a good selection of asters in the fall. You might even find them in the spring. Recently there has been movement in the industry to produce asters on a schedule like the one used for garden mums. They're pretty, but I'm not sure that is garden wise.First, we are blessed with a number of native asters. The most common of these are quite tall. With selection in the wild or in the garden, and some hybridization efforts, you can find a wide range of heights. We're talking anywhere from ankle to head high.
Like mums, asters have composite flowers and a long period of late summer into fall bloom. Think daisy, but a composite is really a clump of many small flowers. Petals may be arranged in tight formation in multiple layers or singly around the flowers. Colors range from almost blue to pink, red, purple and white.
Most asters are clump forming, but need a bit of space in the garden. Even the small ones will give a clump that expands at a good pace. Do not take from the last sentence that they are invasive. They are vigorous, but not invasive.
One exception to the clump forming habit is the Aster tataricus 'Jindai'. This one blooms in October and spreads by root stolons. It came with a 'watch it' warning but in my garden for the last three years it has been well behaved. It's first blooms opened this week.
Most asters want a maximum amount of sun, although there are varieties that are native and thrive in the shade. The shades ones usually have less petals and slightly smaller flowers.
They are not picky about soil and are quite drought tolerant once established. Some of the mid-sized to taller varieties may benefit from staking, but in my garden I give them enough space so that they can flop if they wish.
Selective pinching of the young plants can also control the height and minimize the sprawl. Any plant that is pinched will be stiffer than one that is left unpinched.
The only problem I can think of is that the quality of the lower leaves sometimes suffers during the long growing season. For this reason, as well as their growth habit I would not use them as specimens, but rather as part of the meadow, or as mine often are, the wild garden.
If you are looking for a reliably hardy blooming machine for your fall garden, asters might be an excellent choice.