Christina Pax
Frederick County Master Gardener
Perennial
sunflowers (Helianthus spp.), like their annual
sunflower cousins, have a cheerful yellow bloom. They
are typically smaller both in flower and stature,
although some are still quite tall. They generally
begin blooming in late August-September, then continue
well into October and sometimes even November.
Finches and chickadees love
seeds of perennial sunflowers. As a group, they prefer
good, full sun and a moist, sandy soil and usually
require some room, as they can become tall. They
typically have both opposite leaves (on lower part of
the stem) and alternate leaves (just below flower
clusters).
Do perennial sunflowers always
require full sun?
Helianthus decapetalus,
thin-leaved sunflower or ten-petaled sunflower, blooms
from July through October. It likes full or part sun,
prefers sandy soil and grows from 2 to 5 feet tall,
depending on circumstances. Helianthus divaricatus, or
woodland sunflower, is a good sunflower candidate for
less sunny locations, as its name implies. It prefers
less moisture than other sunflowers, preferring dry to
moist soil. Both are native to Maryland.
Is there a perennial
sun-flower suitable for damp areas?
Helianthus angustifolius,
swamp sunflower, has a pointy-petaled, yellow,
daisy-like bloom with a dark center. This Maryland
native blooms late August through October. Swamp
sun-flower prefers moist, sandy soil of average
fertility.
Butterflies visit these
flowers, and if you let them go to seed, birds devour
seed heads. Once established, a single clump can take
command of 6 to 9 square feet of space in a garden, so
plan accordingly! . Swamp sunflower typically grows
5-7 feet tall and is some-what vulnerable to slumping
over during heavy rain, but if you cut it back in
midsummer, you should be able to keep it more compact
and eliminate any need for staking.
Is Helen's flower also
considered a sunflower?
It's not a Helianthus by name,
but Helen's flower, Helenium autumnale, is in the
sun-flower family. Also (much less glamorously)
referred to as common sneezeweed, it has
anything-but-common wedge-shaped petals that are
broadest at the tip. To add to the curiosity, each
petal has three teeth at the tip, making it one of the
most interesting textures found in a yellow,
daisy-like flower.
Helen's flower is a Maryland
native that blooms July
through November when it
reaches a height of 3 to 5 feet. This one likes a damp
spot in the garden and is an excellent candidate for a
rain garden. It will tolerate drier soils, but will be
shorter and more delicate.
I heard hummingbirds like red
flowers. What can I plant for them that blooms later
in summer?
For the deepest velvety-red
color you can imagine, there is Lobelia cardinalis,
cardinal flower. Although cardinal flower starts
blooming already in July, its habit of opening up the
flowers along its long stalk just a few at a time,
from bottom to top, extends its bloom season long into
October. This seems to suit the humming-birds just
fine. They will some-times stake out a patch of
cardinal flower and even fight over it because it
provides nectar for such a long period of time.
Part sun is better than full
sun for lobelias, as both leaves and blooms fade in
full sun, and I have seen leaves burn where sun
exposure is strong. In the wild, you might see this
flower in small, damp clearings where a little patch
of sun falls to the forest floor, often absolutely
covered with swallowtail butterflies.
Although not as adaptable with
sun requirements, cardinal lobelia will forgive a
departure from its natural, very moist soil
preferences, adapting fairly well to dry locations
once established. Since it is a short-lived perennial,
many gardeners mulch lightly if at all around cardinal
flower to encourage its seeds to sprout and avoid
covering over wintering crowns.
Will hummingbirds visit any
other color?
Cardinal flower's close
relative, great blue lobelia, Lobelia siphilitica,
blooms well into fall and is also popular with
hummingbirds. Great blue lobelia is native to
Maryland's piedmont and mountain regions. It starts to
bloom a little later than cardinal lobelia, usually in
August. Both cardinal and great blue lobelia grow 2 to
5 feet tall.
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