Silphium perfoliatum (Cup Plant)

Westbrook, ME(Zone 5a)

I have some of these sprouting from seeds. Anyone familiar with it? I read they get very tall and like moist soils. Are they well behaved or will it spread all over? Should I plant it in the garden? ... or behind the garden in the field? & How about flopping?.... Does it need to be staked? I don't want to create a nightmare for myself!

Camilla, GA(Zone 8a)

his is long, but interesting..

Silphium perfoliatum L.

Common
name(s):
Cup plant, Indian cup,
Ragged Cup, Carpenter
Weed
Family:
Asteraceae
Type:
Perennial prairie forb
Size:
3-8' high
Texture:
Coarse
Hardiness:
Zone 4a USDA
Range:
Michigan . Alabama . Texas .
North Dakota


Select for a larger image!

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:



Select for a larger image!
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.


Flowers:

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.

S. perfoliatum flowers

Select for a larger image!


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.

Westbrook, ME(Zone 5a)

Thanks Larkie,
That's helpful. I think I'll put them behind the garden and not in it. It sounds like they want more space than I'll have.

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