Cardinal Flower –Nectar for Hummingbirds or a Tonic for Lovers?

Cardinal flower and the ruby-throated hummingbird pollinating it.  Love at first sight?
Photo by C. Magnuson (RWMWD).

By Sage Passi

I fell in love with the cardinal flower years ago when we first planted it in Marian Seabold’s rain garden – one of the many home rain gardens we planted years ago. I must not be the only one who is enamored with this bright red flower. I’ve noticed that the landscape designers who consult on our church rain garden designs also have an affinity for this lovely native wet meadow species, as evidenced by its appearance this year in a number of projects I’ve been keeping my eyes on. Its crimson blossoms stand out as September gardens begin to transition to their fall flowers and summer foliage fades. 



Cardinal flower (Lobelia cardinalis) paired with Great Blue Lobelia (Lobelia siphilitica) in
Our Redeemer Lutheran Church Rain Garden.

 
But alas, cardinal flower, like some loves lost, has a habit of disappearing in our gardens after a while. It’s short-lived so you may have to renew your vows to this flower periodically and plant it again if it doesn’t successfully reseed itself.

Cardinal flower stretches out its blooming time to September.  Left to right: July, August, September, November.

Lobelia cardinalis can grow to be two to four feet tall and is related to Lobelia siphilitica (great blue lobelia); both display the characteristic "lip" petal near the opening of the flower and the "milky" liquid the plant excretes. Each flower has three spreading lower petals and two upper petals, all united into a tube at the base. L. siphilitica has blue flowers and is pollinated by bees; whereas L. cardinalis is red and depends upon the ruby-throated hummingbird for its pollination since most insects find it difficult to navigate the long tubular flowers. Occasionally I have run into other forms that are much paler in color. Delving into this a bit further, I discovered that there are indeed other forms including white (f. alba) and pink (f. rosea) so that answers my question as to why I have seen “white” cardinal flowers on occasion.


Cardinal flowers ablaze in Lakeview Lutheran's rain garden.  Note the "white" form (f. alma)
growing in the midst of the others.

So where should you plant it? In the wild I have come upon it on river banks while canoeing along the St. Croix River. It’s happiest growing in wet meadows, stream banks and along lake edges so that explains why it’s also appropriate to rain gardens. But I have been able to successfully establish it in well drained rich loam or sandy loam in drier conditions as well. It seems to adjust to either full sun or shade so this plant seems to be fairly adaptable. Cardinal flower will take two years to bloom, forming a large rosette the first year. Allow the plants to self-sow. They are heavy feeders, so compost or a shot of granular fertilizer when they begin growth is recommended.
 
As I mentioned in a previous plant story, I like to collect plant lore. The common name and its species name (cardinalis) alludes to the bright red robes worn by Roman Catholic cardinals. My research unearthed multiple stories from native tribes and European lore that indicates that this plant has often been used in love potions and cures. The Mesquaki were known to use cardinal flower in love ceremonies. They put chopped up roots into the food of quarreling couples to help them reconcile their differences. The Pawnee used the cardinal flower as a love charm. They believed that possession of the plant made them irresistible to the one they loved. But I warn you, according to some sources, fatal overdoses have resulted from the improper use of this plant as a home remedy so I recommend caution on this note.


Consider adding these vividly colored jewels to your garden’s palette and sit back and wait for the hovering hummingbirds. But be vigilant or, like these aerial artists that they attract, the cardinal flowers may surprise you with their own disappearing act!

Marian Seabold's cardinal flowers accent her East St. Paul rain garden.