Trunkline Magazine (Louisville Zoo) September 2018 | Page 21
GARDEN TALK
Autumn purples
By Matt Lahm, Asst. Curator of Education
The monarch migration is upon
us! As September arrives, so does
the flight of the monarch but-
terflies. Did you know monarch
butterflies love the color purple? It’s
the color of some of their favorite
flowers! As we prepare for this
year’s Flutter Fest (read more on
page 9) and the season ending of
the Butterflies n’ Blooms exhibit,
learn about two native wildflower
species that would be excellent
additions to add some spectacular
purple hues to your gardens. Both
of these plants are available from
our Butterflies n’ Blooms partner,
Idlewild Butterfly Farm.
Our first species is called
aromatic aster, Symphyotrichum
oblongifolium, and is a native pe-
rennial wildflower distributed over
much of the eastern and central
U.S. It grows 1 to 3 feet in height
and width producing small, daisy-
like flowers less than 1 inch in diam-
eter with violet-blue rays and yellow
centers. It prefers dry soils and full
sun, but will grow in well-drained,
moist soils and partial shade. It is a
hardy plant that can tolerate cold,
heat, poor soils, and drought once
it is established. Aromatic aster
creates showy mounds of blooms in
fall and is excellent for native land-
scape gardens. It can be planted
and transplanted in the spring or
fall and should be cut back after it
goes dormant in late fall/early win-
ter. There are no serious insect or
disease problems that aromatic as-
ter experiences, but it is susceptible
to mildew and fungus which is typi-
cally initiated by the plant remaining
moist for an extended period.
Ironweed, Verno-
nia noveboracen-
sis, is our second
plant choice and,
like the aromatic
aster, it also belongs
to the aster fam-
ily. Ironweed is a native,
herbaceous perennial
typically found grow-
ing in meadows, moist
thickets, with average to
wet soils and full sun. It
can be seen throughout
the eastern U.S. How-
ever, this plant, like the
aromatic aster, tolerates
a wide range of soil
conditions. Ironweed is
another low maintenance plant that
is best planted in the rear of a gar-
den area, as it can reach heights of
6 to 7 feet and spread 3 to 4 feet at
the crown. The plant height may be
reduced by cutting back the stems
in late spring. The most attractive
feature of Ironweed is the cluster
of brilliant purple flowers. Bloom
time for Ironweed is late summer
into early fall. The rusty color and
the plant’s tough stem is the reason
for the ironweed's name with dark
rigid stems topped with contrasting
fluffy seed heads, offering excellent
late season color and texture. An
excellent addition to the pollinator
garden, the brilliant purple-crimson
bloom color is very attractive to
butterflies, and ironweed is a host
plant for the American painted lady
butterfly too!
Top: Aromatic Aster
Middle and bottom: Ironweed
Louisville Zoo Trunkline • Fall 2018 • 21