Cup Plant

Silphium perfoliatum, the cup plant or cup-plant, is a species of flowering plant in the family Asteraceae, native to eastern and central North America. It is an erect herbaceous perennial with triangular toothed leaves, and daisy-like yellow composite flower heads in summer. The specific epithet perfoliatum means "through the leaf." It is commonly found inopen woods, lake borders, ditches, meadows, prairies, and thickets. Once established, cup plant spreads both by seeds and by underground rhizomes that form clones. In favorable conditions, it will spread rapidly often forming large clumps. Cup plant can grow in many different habitats with medium to moist soils. It is most often found in the wild in prairie remnants and other open areas. Many wildlife and pollinator conservation mixes include cup plant because it is such a hardy plant. Cup plant is also becoming increasingly popular in native wildflower gardens. However, its height and tendency to spread may make it appear too weedy for small flower gardens or formal settings.



This perennial plant is remains unbranched, except for the panicle of flowering stems near the apex. The central stem is thick, hairless, and four-sided. The large opposite leaves are up to 8" long and 5" across, which join together around the central stem to form a cup that can hold water, hence the name of the plant. These leaves are broadly lanceolate to cordate, coarsely toothed, and have a rough, sandpapery texture. The yellow composite flowers bloom during early to mid-summer for about 1-1½ months. Each sunflower-like composite flower is about 3-4" across, consisting of numerous yellow disk florets that are surrounded by 18-40 yellow or pale yellow ray florets. The infertile disk florets protrude somewhat from the center and are rather conspicuous, while the ray florets are fertile. The latter produce thin achenes, each with a well-developed marginal wing, which are dispersed to some extent by the wind. The root system consists of a central taproot, and abundant shallow rhizomes that help to spread the plant vegetatively, often forming substantial colonies.


Table of Contents


Height(Avg)

4 - 8 feet


Width-Circumference (Avg)

1 - 6 feet


Approximate pH

4.5 - 7.5


Types of Cup Plants


There are two recognized varieties of the cup plant:

  • Silphium perfoliatum var. connatum (hairy stems; found in a handful of mid-Atlantic states)


  • Silphium perfoliatum var. perfoliatum (extremely common throughout the central and southern United States)


Growing Cup Plant


How to Grow Cup Plants From Seed


The easiest time to start a crop of cup plants from seed is in late fall:

  1. Sprinkle seeds on open soil, and gently press the seeds into the soil.

  2. Cover the area with a light layer of straw to help retain moisture and prevent birds from eating the seeds.


If you'd like to plant in the spring, you'll need to stratify (chill ) the seeds for 60 days before planting:

  1. Mix the seeds with moist sand and place them in a refrigerator or a cold location outdoors.

  2. After 60 days, in early spring, plant your seeds and keep the soil moist to ensure germination.


Cup Plant Care


Because many gardeners and gardening centers consider the cup plant weed-like, growing your plant from seeds is recommended (it may be difficult to find a plant in your local garden center). It's easiest to start from seed by planting outdoors in the fall, but planting in the spring is possible, too. Just be sure you'll have a full 60 days of cold stratification before sowing the seeds. Cup plants grown from seeds likely won't bloom until at least their second year of growth. During this period, keep the cup plant well-watered and free of weeds.


Fortunately, cup plants are generally resistant to serious insect infestations or diseases. Large crops of cup plants may be susceptible to the fungus Sclerotinia, but it's rare in gardens.


Light


Although cup plants are extremely hardy, six to eight hours of full sun is recommended for optimal growth. If full sun isn't available, the cup plant can thrive in partial sun, too. If you live in a colder zone, consider planting your cup plants in a spot with full sun and little to no wind.


Soil


Because the cup plant has a large native range, it can grow in a variety of soils, but best tolerates medium-to-wet soil, or soil rich in clay. If you want to achieve taller cup plants; plant them in wetter soil; if you want shorter cup plants, drier soil is best.


Water


The cup plant can tolerate heat and drought but prefers regular watering. Be careful not to overwater your cup plants.


Temperature and Humidity


As previously mentioned, the cup plant is extremely hardy and can grow in a variety of climates and locations. Its growing zones range from the cold zone 3 (last frost around May 15th and first frost around September 15th) to the very warm zone 9 (last frost date of March 1st and first frost date of December 15th).


Fertilizer


Thanks to its hardiness, commercial fertilization isn't required for cup plants in gardens, prairies, or naturalized areas. If you want to give your cup plants additional protection, opt for compost or composted manure as a drop dressing on the roots.


In larger crops, fertilizing is recommended as early as possible during the first year of the cup plant's growth to protect the roots. Some studies of larger cup plant crops have shown that fertilizing is not required in the cup plant's second year.


Propagating Cup Plants


Because cup plants are such vigorous and expansive growers, propagation is rarely a concern. If you would like to start a new patch of cup plants, simply dig up an existing plant and transplant it elsewhere in your landscape. Water well, and the plant should propagate itself.


Pests and Diseases


Pests


Red aphids are occasionally found on the underside of the leaves. Medium numbers of leaf beetles and lygus bugs. Small numbers of Japanese beetles, leafhoppers and thrips.


Diseases


A number of fungal diseases, including Sclerotinia spp. (stems), Fusarium spp. (seeds), Alternaria spp. (seeds and biomass) and Botrytis spp. (seeds, flower buds). Other potentially pathogenic species diagnosed from cup plant include the fungi Uromyces silphii, Uromyces junci, Septoria silphii, Puccinia silphii, Puccinia obtecta, Puccinia albiperidia, Ascochytasilphii sp. and the disease Pseudomonas syringae.


Uses


Medicinal uses

  • Root decoction is used for regulating periods, treat morning sickness and prevent premature child birth.

  • Root is antispasmodic, alterative, emenagogue, diaphoretic, febrifuge, emenagogue, stimulant, hepatic, tonic and styptic.

  • It is used for treating liver and spleen disorders.

  • Use the root decoction internally for treating back pain, chest pain and lung hemorrhages.

  • Apply the moistened dried root to wounds to halt bleeding.

  • Use it as a chewing gum for preventing nausea and vomiting.

  • Root decoction is used as a face wash.

  • Resin is used in chewing gum to freshen breath.


Culinary uses

  • Inhale the smoking roots and use it for treating neuralgia, head colds, stomach ailments, rheumatism and vapor baths.

  • Root tea was used for enlarged spleens, fevers, lung bleeding, internal bruises, general debility, ulcers, liver ailments and female problems.

  • An ointment ad extract is used to heal burns.

  • Chew the dried resinous sap as gum and used for freshening breath, cleaning or whitening teeth and also to prevent vomiting.

  • Young leaves are cooked and consumed as potherbs.

Other uses

  • Used as pollinator and bird-friendly ornamental garden plants.

  • Used as animal fodder.


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