PlantFiles: Cup Plant
Silphium perfoliatum

Grows extremely well in the back corner of my yard. It gets shaded in the morning by the neighbor's trees, but right before noon it starts getting direct sun, and has that for another 4-6 hours. I didn't stake it in any way this year, and it did flop down, but then curved back up to reach about 4'. Allowing it to flop caused it to take up about 3-4'. I didn't experience any difficulty getting seeds from it this year. The seeds are attractive to Yellow Finches, and the cup formed by the leaves at the stem draws insects as well as small frogs and birds. Very dependable and a striking addition if you have the room.

A great addition to a rain garden, slough, or swale that both dries out and gets a bit more water when it does rain (at least in the upper midwest). It can tolerate some drought as well as the flooding of a raingarden. It gets very tall and has very large leaves (v. sunflowerish in habit, although with numerous small yellow flowers rather than the enormous flower of the sunflower), so it needs to be in with some other tall plants so it doesn't look out of place. It blooms for a couple months starting in mid summer, and the blooms attract a large number and variety of insect pollinators (butterflies and bees of all sorts, among others).

Beyond pollinators, it is an exceptional wildlife plant. The leaves form a cup which holds water that birds and insects take advantage of for drinking. The insects drawn to the water, in turn attracts birds looking for food as well as water. A number of birds seem to really love the seeds, especially goldfinches. We don't use a feeder to attract goldfinches, but once the cup plant starts blooming they are frequent visitors (the number increases as our agastache foeniculum seeds start maturing, & continues well into the fall). As the seeds start to mature and attract birds while the plant still is in bloom, you get several months of bloom and wildlife activity.

Native roadside plant. I'm not sure if it was meant for captivity. I think it might be best to leave it in the wild.

The best of show and worst of show results in a neutral vote. We have grown this in our nursery garden in South Dakota. I love its uniqueness, drought tolerance (though suggested for moist sites), showy yellow flowers, attraction to birds and more. One problem though is that this plant, at least in the north where seed gets cold stratification, can self sow to the point of being very weedy and a big problem if first year seedlings are not dug out right away.

The Master Gardeners have a demonstration garden in Palo Alto California where I planted the seeds 2 years ago. The first year the plant stayed at less than one foot high and I forgot about it among the many plants along the fence. This year it is about 8 feet high and full of brilliant yellow flowers blooming at a time (Sept) when other plants are finished. A very satisfying plant for a big garden.

Long-tongued bees, butterflies, and skippers are common visitors and the most important pollinators of the flowers. Some short-tongued bees, wasps, bee flies, and other kinds of flies also visit the flowers for pollen or nectar. The larvae of an Antistrophus sp. (Gall Wasp sp.) feed within the stems of this plant, and may attract the hyperparasitic wasp Eurytoma lutea. Various birds, especially goldfinches, are very fond of the seeds, and drink water from the cups formed by the leaves. Because of the tendency to form dense colonies, this plant provides good cover for birds, which often lurk among the leaves during the heat of the day, searching for insects or pausing to rest. Large herbivores, especially cattle, may eat the eat leaves of Cup Plant, especially those of immature plants.

I've had this plant in London, UK, for about 4 years. Despite the sheer number of flowers produced, for some reason, viable seeds are extremely few. In the first year or so I collected about 6. Last year was a big improvement however. In a smallish garden one plant is quite sufficient, as it increases in spread from year to year. This year,in order to halt its spread, we literally chopped off some of the outside portions with a spade. I'm sure that the 'offcuts' would have grown if planted. The plant also suffers heavy attacks from snails. It makes a lovely specimen plant, the flowers being the first thing that catches the eye.

Has cheerful yellow daisy-like flowers on long, stout stalks reaching up to 8' in height. Even more interesting than the flowers are the coarse leaves from which it gets its name. Borne opposite one another on the stem, the large leaves fuse together at their bases to form a "cup" of sorts.These cups catch and store rainwater, often for many days. Birds and butterflies often come for a drink, and hummingbirds regularly visit .In fall goldfinches enjoy the seeds.

Note added 5-24-06. I have grown this plant for several years I have to agree you don't get many viable seeds.