I am being stalked by cardinal flower—Lobelia cardinalis. Otherwise known as red lobelia, the plant is tall and handsome, rising just shy of three feet and producing brilliant red flower spikes in mid to late summer. The flowers are so red that they knock you for a loop when you first see them.
That happened to me when I caught site of a stand of cardinal flowers at the Leonard J. Buck Garden in Far Hills, New Jersey. They bowled me over a second time last week when I saw them in the company of blue globe thistle—Echinops bannaticus—in a home garden. Not only were the cardinal flowers glorious, they formed a dynamic duo with the globe thistle. Those of us who love gardens, love discovering a good plant combination. Cardinal flowers and globe thistles are made for each other.
Cardinal flower is a native perennial, hailing from wet locations all over the eastern half of North America. It is sometimes also known as “Indian pink.” Up close, the flowers are fascinating. Clustered at the tops of the tall stalks, each small, individual flower has two “lips” or modified petals that are joined at the base to form a tube. This adaptation makes life easier for the hummingbirds that pollinate the cardinal flower, not to mention making it lovely for the people who watch the hummingbirds going about their feeding and pollinating business. While watching the hummers, you may also see butterflies trying to muscle them aside so they can help themselves to the nectar within those red blooms.
Cardinal flowers are back-of-the-border plants. Left to their own devices they will also form good sized clumps, making their annual appearance even more dramatic. The lobelias I saw in a home garden were watered regularly by an automatic sprinkler system. If you don’t have a damp spot for your cardinal flowers, make sure they get regular moisture during dry spells. A soaker hose works well for this, keeping the ground damp and minimizing water evaporation.
Globe thistles are tall enough to stand side-by-side with cardinal flowers and they bloom at approximately the same time. You would never know it by looking at the spiky blue balls, but globe thistles are members of the daisy or Compositae family. There is certainly nothing dainty about the rough-looking, deeply dissected leaves that are green on top and lighter—almost white—on the bottom. The stalks are rough and stiff. In fact, the plants might be easily mistaken for weeds except for the magnificent, steel-blue, spherical flowerheads. Globe thistle heads are about the size of large golf balls and they have the same garden effect as some of the tall alliums. They are dramatic in cut-flower arrangements as well, if you can spare a few from the garden.
I usually gravitate towards impressionistic garden color schemes, with swathes of color that melt into each other. Globe thistles and cardinal flowers do not melt. They make bold statements individually and even bolder ones together. Like many successful couples, they accomplish this because one half of the pair—globe thistle—goes out of its way to be accommodating. Often these daisy-family denizens are planted in poor, rocky or sandy soil, where they succeed beautifully. However, to make beautiful music with cardinal flower, globe thistle will make sacrifices, accustoming itself to the luxurious life of uniformly moist soil. Not only that, but it will also form clumps, allowing savvy gardeners to divide them eventually and repeat the cardinal flower/globe thistle combination elsewhere in the garden.
Cultivated varieties of old favorites like cardinal flower and globe thistle are usually great or slight improvements on the originals, with bigger flowers, different growth habits or color variations. ‘Taplow Blue’ is my favorite globe thistle because of its brilliant blue color. It retains the four-foot tall stature of the species. “Blue Glow”, which may be a bit shorter, is another good variety. An attractive, closely related globe thistle is Echinops ritro. It is about the same size as the bannaticus species, but the flowers are closer to blue-purple. I especially like ‘Veitch’s Blue”.
Bronze purple foliage is always a plus in the landscape. “Queen Victoria”, a cardinal flower variety, has it, with the bright red flowers blooming atop dark stems that rise from basal clumps of equally dark foliage. The bronze-purple foliage makes a nice complement to globe thistle’s coloring as well. If you have the space, plant groups of three each of regular cardinal flower and ‘Queen Victoria’, mingled with a couple of three-plant clumps of globe thistle for a great block of late summer color.
You may be able to cardinal flower and globe thistle at local nursery and garden centers that stock perennials for fall planting. If not, try Bluestone Perennials, 7211 Middle Ridge Rd, Madison, OH 44057; (800) 852-5243; http://www.bluestoneperennials.com. Free catalog.