Asters: Stars of the Fall Garden

A native American plant, the aster got its name from the ancient Greek and Latin words for “star,” describing its radiant blossoms. (Another of its common names is starwort.)

As early as 1680, Europeans were importing our native wild asters for use in their Old World gardens, although Europe has its fair share of asters as well! In England today, they are sometimes called “Michaelmas daisies” due to their habit of blooming around the same time as the Feast of St. Michael (Michaelmas) on September 29th.

Asters are also the birth flower for September.

The Perfect Fall Perennial

Like many native plants, asters are often overlooked when people plan their flower beds, but the reliability of their stunning blossoms during a time of year when other perennials are winding down is something we should be taking advantage of. They not only rescue the fall garden from boredom but also provide nectar for the butterflies that are topping up before heading south for the winter. They thrive with minimal care and there is a galaxy of starry asters to choose from, including the ones listed on this page.

An Aster by Any Other Name…

In the 1990s, the Aster genus underwent a bit of reshuffling. The genus was split into multiple genera, with most of our familiar North American species being reclassified under Symphyotrichum and the European species remaining under Aster. Regardless of this change, we still refer to both genera by the common name of “asters,” although the Latin names have been updated accordingly.

Types of Asters

New York asters (Symphyotrichum novi-belgii) grows 2-3 feet tall with violet-blue flowers and narrow leaves. There are cultivars in dark blue, lavender, and pink too. The dwarf form grows only 10-15 inches high and spreads readily.

New England asters (S. novae-angliae) are late bloomers, grow 3-6 feet tall and are well branched with lots of small purple flowers.

Cultivars of the New England aster include:

• ‘September Ruby’ is a deep cerise-red variety that grows easily from seed. At maturity, it will be about 5 feet tall.
• Hot pink ‘Alma Potschke’ grows 4 feet tall and is perfect for a back of the border accent.
• ‘Purple Dome’ is the first true dwarf NE aster, growing only 18 inches tall. It will be covered with deep purple blossoms for at least a month.

If powdery mildew plagues your garden in fall, bushy aster (S. dumosum) is a low-growing ground cover that is 8-12 inches tall. Try ‘Woods Purple’, ‘Woods Pink’, or ‘Woods Blue’. They all appreciate full sun and are mildew free.

Not to be overlooked is Frikart’s aster (Aster x frikartii ‘Monch’), which is long blooming, grows 2-3 feet tall, and bears large 2½-inch lavender-blue flowers. (Note that it is a non-native cultivar, however.)

Though most asters require full sun and lots of water, there are some varieties that are drought tolerant and thrive in partial shade:

The smooth aster (S. laeve) is mildew resistant and performs well in dry shade. It grows 3-5 feet tall and has fleshy dark green leaves on dark purple stems. The variety ‘Bluebird’ bears clusters of sky-blue flowers atop a vase-shaped plant.

The white wood aster (S. divaricatum) bears a cloud of white blossoms atop dark brown, wiry stems. A woodland plant, it spreads by seeds and underground runners. It will thrive in the dry soil and dappled shade found under tall oaks and maples but can be invasive.

The blue wood aster (S. cordifolium) has heart-shaped leaves and grows up to 6 feet tall in the right location. It tolerates shade well but prefers rich, humus. It will reward you with a dense cloud of small blue flowers from late summer through mid-fall.

Aster Growing Tips

To promote bushier growth, cut your asters back in early spring and again in June. During a dry summer, they tend to drop their lower leaves if not kept well watered. To cover their “naked legs,” plant lower understory plants around them.

As the plants mature, they grow out from the center and eventually leave a dead spot in the middle. They benefit greatly from dividing and replanting in the spring every 3 to 4 years. Feed plants in the spring with a top dressing of compost or well-rotted manure. Tall growing varieties will need staking. Read more about growing asters here!

Make some room in your garden for one or more of these stellar performers!