Introduction:-
A native of the tallgrass prairie, this perennial giant sports wonderfully cheerful yellow daisy-like flowers on long, stout stalks reaching up to 8' in height! Its color is a welcome sight in our hot, humid Midwestern summers, providing some distraction when little else is blooming.
Even more interesting than the flowers are the coarse leaves from which this species gets its name. Borne opposite one another on the stem, the large leaves fuse together at their bases to form a "cup" of sorts. Even on the hottest summer days one can usually find water from the morning dew collected within these miniature green receptacles.
Although Silphium perfoliatum is rarely seen in the garden, it should still be considered for those with lots of sunny space. The clean, dark green foliage makes an excellent backdrop for smaller perennials, and the bright yellow blooms are airy enough to not compete with any neighbors for visual prominence.
Foliage: -
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The leaves are the truly distinguishing feature for this
species. Borne opposite one another on a stout, squarish
stem, the leaves fuse together at the base forming a "cup"
that often holds water after a rain.
Taxonomic description:
Opposite and simple, broadly triangular to ovate. Upper
leaves connate-perfoliate, clasping 4-sided stems. Lower
leaves abruptly contracted into margined petioles. Scabrous
above and pubescent beneath, from 6-12" long to 4-8" wide.
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Flowers: -
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Appearing around the 10th of July through October 9th
in the Chicagoland area, the bright yellow flowers are
between 2 and 3 inches in diameter. They're held on
stalks high above the plant, resembling giant yellow
daisies in summer.
Taxonomic description:
Numerous heads 2-3" in diameter, rays 20-30. Involucre
depresed-hemispheric, outer bracts broad, ovate, ciliolate,
spreading or erect.
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S. perfoliatum flowers
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Fruit: -
The fruit is a brown obovate achene with an emarginate apex,
appearing in autumn. Sometimes 2-toothed.
Pathology: -
There are few pest or disease problems with S. perfoliatum,
although occasional borer infestations have been known to
attack unopened flowers.
Propagation: -
Although I've never tried this species myself, propagation
is supposed to be easy from moist stratified seeds. Collected
in fall, the seeds need to be stratified for 12 weeks. They
can then be sowed at 24 to 39°F for 4-8 weeks, then
moved to 68°F for germination.
Culture: -
Native to the tallgrass prairies of the Midwest, this species
prefers moist areas along prairie streams, in floodplains,
or along the edges of woodlands.
It transplants readily when young, but older plants develop
an extensive root system that makes transplanting more difficult.
Suggested uses: -
Silphium perfoliatum's coarse texture and massive
size limit it for all but the largest gardens, but in those
environments it makes a perfect backdrop or strong accent.
It's best in an area with slight moisture and full sun, but
will tolerate dry clay environments.
Companion plants: -
Floodplains near streams:
Acer negundo, Acer saccharinum,
Actinomeris alternifolia, Ambrosia trifida
Asarum canadense, Campanula americana,
Celtis occidentalis, Cryptotaenia canadensis,
Elymus virginicus, Fraxinus americana,
Galium aparine, Geum canadense,
Hydrophyllum virginianum, Laportea canadensis,
Lysimachia ciliata, Osmorhiza longistylis,
Ranunculus septentrionalis, Rhus radicans,
Rudbeckia laciniata, Sambucus canadensis,
Saniucula gregaria, Ulmus americana,
Urtica procera, Viola sororia,
Zizia aurea.
Calcareous springs:
Impatiens capensis, Solidago patula,
Symlocarpus foetidus.
Medicinal uses: -
Indian cup's most common use by Native American Indians wasn't
exactly medicinal
it was used for chewing gum. When the top of a cup plant stalk
was snapped off, a large blob of resinous sap would slowly ooze
out and eventually harden. This hardened sap could be chewed
and is said to freshen breath.
Some tribes, like the Winnebagos, attached much more importance
to the plant. Believing that it had supernatural powers, braves
would drink a concoction derived from the rhizome to purfiy
themselves before embarking on a buffalo hunt or other important
undertaking.
The Chippewas used an extract from the roots for back and chest
pains, to prevent excessive menstrual bleeding, and as a means
to stop hemorrhaging from the lungs.
References:
- Griffiths, M. The Index of Garden Plants. Portland: Timber Press, 1994.
- Ladd, Doug. Tallgrass Prairie Wildflowers. Helena: Falcon Press, 1995.
- Mohlenbrock, Robert H. Guide to the
Vascular Flora of Illinois. Carbondale:
Southern Illinois University, 1986.
- Newcomb, Lawrence. Newcomb's Wildflower
Guide. Boston: Little Brown, 1977.
- Reader's Digest. Magic and Medicine of Plants. Pleasantville: Reader's Digest, 1993.
- Rickett, Harold William. Wild Flowers of the United States: The Northeastern States, vol. 2. New York: McGraw-Hill, 1966.
- Swink, Floyd and Gerould Wilhelm. Plants
of the Chicago Region. Lisle: Morton Arboretum, 1994.
- Voigt, John W. and Robert H. Mohlenbrock. Prairie Plants of Illinois. Illinois: Department of Conservation.
- Walters, Dirk R. and David J. Keil.
Vascular Plant Taxonomy, Third Edition.
Dubuque: Kendall / Hunt, 1977.
- Wyman, Donald. Wyman's Gardening Encyclopedia. New York: MacMillan, 1986.
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