The cardinal flower (Lobelia cardinalis) is a beautiful perennial that can be found in gardens across the United States. These plants attract hummingbirds, easy to grow, and tolerate a variety of conditions. Blooming from late July to the early September months, this plant attracts pollinators with its intensely bright red flowers. However, it’s essential to consider the best cardinal flower companion plants to ensure a beautiful and healthy garden.
Swamp Milkweed
Swamp milkweed is a great companion plant for cardinal flowers. This perennial blooms pink or white flowers and is a host plant for the monarch butterfly larvae. It can be found in moist areas, such as meadows, marshes, and stream banks. Because of its height (it can grow up to 5 feet tall) makes an excellent backdrop for the cardinal flower. Additionally, the swamp milkweed’s leaves will provide some food for the monarch butterfly larvae.
Spotted Water Hemlock
The spotted water hemlock is a poisonous plant that should only be planted if you are an experienced gardener. This plant is a host for the caterpillars of the Io moth and Attacus atlas moth. Typically found in wetlands, this plant can grow up to 10 feet tall. Its white flowers bloom from May to July. Its height and unique leaves make it a great addition to a garden with cardinal flowers. The spotted water hemlock can be easily mistaken for cow parsnip when it’s not in bloom.
Aside from helping attract pollinators, the spotted water hemlock also acts as a natural fence and helps retain moisture in the soil. These conditions significantly improve cardinal flower growth.
Large Blue Lobelia
This perennial blooms blue flowers and grows up to 3 feet tall. Like cardinal flowers, it thrives in moist environments and is a host plant for the caterpillars of the Great Spangled Fritillary butterfly. In general, the large blue lobelia makes a great addition to any garden and is tolerant of various growing conditions. They can be found flowering from July to September.
Monkey Flower
The monkey flower is a great companion plant for cardinal flowers because it thrives in moist environments, just like the cardinal flower. This annual blooms yellow flowers with a purple throat and is a host plant for the caterpillars of the Pipevine Swallowtail butterfly.
Caring for both flowers is easy, as both plants like full sun to partial shade and moist soil. More importantly, both plants attract pollinators. As you may have noticed, pollinators play an important role in the growth of cardinal flowers. Cardinal flowers lack nectar, so they rely on pollinators to move pollen from one flower to another.
Bristly Buttercup
The beautiful bristly buttercup blooms yellow flowers and has fern-like leaves, with white hairs along the edges. This plant is a host plant for the caterpillars of the Eastern Tailed-Blue butterfly. In addition, these flowers are famous for their ability to attract hoverflies. Hoverflies are important pollinators, so by planting bristly buttercups, you’re indirectly helping the cardinal flower.
Water Parsnip
Considered a weed by some, the water parsnip has beautiful white flowers that make a great companion plant for cardinal flowers. Growing up to 3 feet tall, water parsnips can help to shade cardinal flowers and form a dense ground cover. It’s important to note that all parts of the water parsnip are poisonous, so only plant it if you’re sure it won’t be a problem for pets or children.
Larger Aster Species
Many larger aster species make good companion plants for cardinal flowers. These include New York Ironweed, Joe Pye Weed, and Purple Coneflower. These plants grow tall (3-5 feet) and have large flower heads.
Virginia Creeper
Virginia creeper is a climbing vine that can be used to form a natural fence or trellis for cardinal flowers. The vines are covered in small, dark green leaves and produce clusters of small, white flowers in the fall. Virginia creeper grows well in shade or partial shade and is an excellent choice for gardens with limited space.
Blue Vervain
The blue vervain is known to be a sacred herb to the Native Americans. This perennial blooms blue flowers that are great for attracting pollinators. It’s perfectly paired with cardinal flowers along with other perennials in a garden. Often, vervain is used as a medicinal herb.
Wild Iris
Among the many great companion plants for cardinal flowers is the wild iris. This perennial blooms purple or lavender flowers that smell amazing. Commonly seen in shady areas, many different types of butterflies are attracted to the wild iris.
Swamp Rose
Last but not least, the swamp rose is another great companion plant for cardinal flowers. This perennial can grow in wet areas, making it a perfect choice for a garden with moist soil. It produces sweet-smelling white or pink flowers, and butterflies are drawn like magnets. Plant it next to your cardinal flower plants for a beautiful and functional garden display!
Cardinal Flower Companion Plants: Final Thoughts
While many plants can be used as companion plants for cardinal flowers, the ones listed above are some of the best options. By using these plants in your garden, you can help to create a beautiful and pollinator-friendly landscape. Not only will you be adding some beautiful flowers to your garden, but having these plants significantly helps the ecosystem!
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