September’s Native Maryland Plant
Silphium perfoliatum L. var connatum
(SIL-fee-um per-foh-lee-AY-tum var kon-NAH-tum)
Common Name: Cup Plant
During September, historically Maryland’s wettest month, I visit the ten rain barrels in my yard frequently - removing any debris from their screens and doing my best to drain them before the next storm. Two years ago, I planted what I thought was the straight-species Silphium perfoliatum in front of the three 65-gallon cascading barrels above; the plants were a surprise gift from my friend, a notably experienced and excellent gardener. They were already big plants with well-established roots, so I had high confidence they’d succeed being replanted. I knew they would flower best in full sun and that they could be aggressive spreaders so I sited them where they could ‘dress up’ my rain barrels and be somewhat contained. So far it appears this is a case of ‘Right Plant, Right Place’ as well as a case of ‘Wrong Plant, Wrong Place’.
Let me explain. The plant has flourished, its natural habitat includes road-side ditches and disturbed sites; it has also proven worthy of its common name - Cup plant. In May its meristems (young growth) are fully emerged, and the large serrated and sessile leaves have already formed a cup that captures rain and provides drinking water for bees and birds. The hairy stems are one characteristic that set this species apart from the straight-species and how I identified this plant as var connatum. i.e. the ‘wrong plant’. I’ve read it’s native to the mid-Atlantic states, but lists disagree on whether that includes Maryland.
Silphium spp. have a long bloom period and provide an abundance of flowers for pollinators. Their seed heads are enjoyed by birds in the fall. They are highly adapted to endure extreme weather and inhospitable site conditions – as they’ve shown in my garden where they’re in a highly exposed location, susceptible to wind and disturbance.
When accepting plants from friends or neighbors I’d like to offer a note of caution. In my experience, most people give plants from their garden because they have an excess of them – they do it in good faith and in friendship, never intending to do harm. However, frequently the ‘gifted’ plants are aggressive, non-native plants that can displace native plants – in the past I’ve been offered Daylilies (Hemerocallis spp.) and Lily-of-the-Valley (Convallaria spp.), two plants I know better than to plant due to their invasive nature. I’m always hesitant to accept plants as a gift, I have limited space in my yard, I give preference to certain plants, and I try my best to only plant natives. I’ve been impressed with this Cup plant; it’s shown itself to be adaptable and very attractive to pollinators – combined with its water-storing ability I find it the perfect blooming companion to my rain barrels.
~ Alison Milligan – Mstr. Gardener/Mstr. Naturalist/Mstr. Watershed Steward
Chesapeake Bay Landscape Professional (CBLP)