Cup plant – Silphium perfoliatum

Just when you think you know “everything” about a plant that you think makes it useful, some plants give you a surprise. This is especially true when it comes to the cup plant. This unique plant forms “cups” that hold water where they connect with its thick square stem. But that’s not all:

A stand of cup plants at the NW corner of the greenhouse

Cup plant flowers beginning to bloom

Cup plant flower in its fullness and some young buds

Healthy and parasitized aphids under a cup plant leaf

Cup plants seeds 2008

A leaf that is lightly infested with aphids, showing some light parasitization

Red aphids just beginning to become parasitized

Cup plant leaf with healthy and parasitized aphids

Hollowed-out dead cup plant stems used for orchard mason bee nesting tubes

If you were smaller…and if you laid eggs…you’d want to go in, too.

When planted in a thick row and well watered, this towering plant can reach superhuman heights of EIGHT feet! And its miniature sunflower-shaped flowers provide great pollen fodder for foraging bees.

The cup plant also…and this is a good thing thing, mind you…attracts a species of red aphid (Macrosiphum spp.). Common sense would have you believe that al aphids are unwanted.

However, the cup plant is able to withstand the Macrosiphum aphids, and because it does it attracts several species of beneficial aphid predators and parasitic wasps. In fact, even though the aphids colonized nearly the entire underside of the plant leaves, lacewing and syrphid fly maggots and parasitic wasps were able to control them naturally.

And surprise of surprises, one other benefit of the cup plant is its thick square stem’s pith can be hollowed with a dowel out to create the tunnels orchard mason bees need to lay eggs.