Our gardening grandparents may have
known Asters as 'Starflowers', New England asters, or Michaelmas daisies. 'Aster' in Latin
means 'star', they do thrive in New England (and quite nearly everywhere else), and
Michaelmas Day comes at the peak of Aster bloom season. No wonder people get confused
about this large family of mostly perennial plants. Over 200 species of Asters are native
to both North America and Europe; transatlantic transplants began as early as the 1600s.
Natives to both worlds and hybrids between them have earned their reputations as reliable
Asters belong in every garden, large or small, wild or well
manicured, from windswept northern prairies to sunny subtropics. They can lend a blowsy
cottage effect or form a crisply neat edging. All produce distinctive flowers, and attract
butterflies across an incredibly wide range of plant sizes and habits. The leafy,
multibranched plants reach from 6" to 7' tall, depending on variety. Fine textured
flowers have silky, slender rays in purple shades, white, and even red surrounding red or
orange disks. Their current popularity owes to recent wider availability of both the
natives and hybrid varieties. One or more will be perfect for your garden.
All asters prefer full sun when grown north of Zone 7 and at
least 6 hours of sun in zones 7-9. Give them good drainage and uncrowded growing
conditions; soggy winters damage the crown and inadequate air circulation can lead to leaf
diseases. Plant them so the crown breaks the soil surface, mulch around but not over it,
and space as the variety demands to circumvent these problems. Any good garden soil will
sustain asters, but extended drought reduces flowers and plant vigor. Keep the base of the
crown mulched and gently work decaying mulch into the soil for continuous feeding.
Water asters deeply and regularly during the growing season. If
leaf diseases persist, use dusting sulfur or spray with 1 T baking soda dissolved in 1/2
gallon of water weekly or as needed. Most varieties will topple over if not pinched back
twice (spring and early summer) to encourage branching. Stake the tall ones early in the
season anyway for best results. Cut stems down to ground level after flowering. Divide the
clumps every other year, replant the new growth, and discard the very center. This
treatment allows these fast growing plants to constantly renew themselves.
Success with asters often means selecting the right one for your
garden. 'Wonder of Staffa' (Aster x frikartii) makes an especially fine show in small and
low-maintenance gardens. Two to three feet tall, nearly as wide and beloved for its
fragrance, this one also has a longer bloom season than other asters. Divide only after
three years. 'Monch' (A. frikartii) has stiffer stems and flowers in a light shade of
A native of the Midwest and West, Aster oblongifolius thrives
throughout zones 5-8. An excellent choice for edging at eighteen inches tall, these asters
bloom in dazzling violet. At the other end of the spectrum, the Tartarian aster (A.
tataricus) approaches seven feet tall with lower leaves often two feet long. This huge
plant bears violet blue daisies in fall, makes an ideal garden companion for perennial
sunflower (Helianthus angustifolius), and is hardy to Zone 3.
Oregon Pacific asters thrive in the Northwest. These hybrids
blend a native and one of the michalemas types to produce plants 12" to 30" tall
that are best described as floriferous.
The popular name 'Michaelmas daisies' actually can refer to two
different types of asters:
New England asters (A. novae-angliae) can be distinguished as
being a taller plant with flowers that close at night. Their fabulous yellow disks with
bright purple, violet, or pink rays stay open for weeks in late summer and early fall.
New York asters (A. novi-belgii) are shorter plants that have
been hybridized widely to produce free-blooming plants in vivid shades of fuschia, violet,
neon pink, and white. Selected for mounding habit, these respond well when cut back in
spring and early summer.
ASTERS FOR EXTREMES:
Hardy Aster alpinus (A. alpinus) blooms in late spring unlike
other asters. A foot tall or less, with flowers up to two inches across sprouting up from
a rosette of leaves, alpinus thrives where winters are coldest. The violet blue, pink,
white, or red daisies thrive in rock gardens, slopes, and banks.
Deep south gardeners (below zone 8) can depend on Linear Leaf
Native Aster (A. hemisphaericus). Two feet tall with skinny leaves often eight inches
long, this good looking plant sports light purple flowers in late summer.