by Mary Free, Extension Master Gardener
Pollinators such as bees, butterflies, and hummingbirds gravitate to gardens that bloom throughout the growing season and that contain an abundance of the same plant species as well as a diversity of species of like colors arranged together. Annuals, with their extended bloom period, ensure a continual nectar source for pollinators when perennials have yet to flower or are in decline. Herbs are also an asset in a pollinator garden, but that is for a future posting.
Seed companies and local nurseries offer a wide variety of annuals. To help you choose the right plants for your property, consider the five easy-to- grow, low-maintenance annuals described below. They have successfully grown and attracted pollinators in the MGNV demonstration gardens.
Commonly known as globe amaranth, this compact annual native to tropical America grows 6–24 inches tall in full sun (preferred) to light shade. It tolerates heat well, although it is mildew-prone during drought conditions. With its long bloom time—early summer to frost —it is desirable in a pollinator garden, in a vase freshly cut, and in dried flower arrangements (just hang upside-down in a well-ventilated location to dry). Although hybridized to many colors, magenta is the original and preferred species. Gomphrena invites pollinators such as bees, moths, and butterflies (e.g., monarch, orange sulfur, various skippers), but rarely attracts deer. Watch this video to see pollinators in action on Gomphrena.
Native to the West Indies and the American tropics, this “frost-tender” perennial shrub grows 3–6 feet tall in full sun and blooms midsummer until frost. Showy and easy to grow, Lantana is often used as a bedding annual rather than overwintered indoors. Pruning the tips will encourage repeat blooming and pruning by one-third can contain vigorous growth. A few plants can be cold-hardy to Zone 7, so these should be pruned back hard in early spring.
Some Lantana cultivars produce shiny blue/purple ornamental drupes, which are poisonous if eaten. If this is a concern, then purchase sterile varieties. Research shows that Lantana has an allelopathic effect, i.e., it releases biochemicals that can affect nearby plant life. This is more likely to be a problem in places like Florida where Lantana has become invasive and is altering the plant community. If this is a concern, then growing it in a pot should mitigate adverse effects. Lantana, which is deer-resistant, attracts bumble bees, hummingbirds, butterflies (e.g., eastern tiger and other swallowtails, monarch, various skippers) and moths like snowberry clearwing. According to “Capital Naturalist” Alonso Abugattas, pollinators may favor the species Lantana montevidensis.
This Mexican native annual easily grows 1–2 feet tall in full sun and self-seeds in optimal conditions. Blooms appear late spring until frost without deadheading. Although Master Gardeners have observed syrphid flies and butterflies on the flowers, Melampodium does not have a reputation for attracting myriad pollinators. Regardless, its abundance, color, and continuity of bloom even in hot and humid areas make it a welcome addition to a pollinator garden or sunny border.
If you prefer a more-pollinator-friendly species, the three annuals below (listed in alphabetical order) may be considered as substitutes, but they have their own drawbacks.
- A popular annual bedding plant, Cosmos bipinnatus (garden cosmos) provides nectar to a variety of birds, bees, and butterflies, but it naturalizes readily and has been found to be invasive in parts of the mid-Atlantic region.
- Dahlia, showy and highly attractive to pollinators like hummingbirds, bumble bees, and monarch butterflies, is often grown as an annual, but it can be high-maintenance and is susceptible to a number of diseases.
- Helianthus annuus (common sunflower) is a native annual that has been cultivated by Native Americans for more than 3,000 years. It attracts over 150 species of insects and numerous game and song birds. Varieties grow 2–10 feet tall and may require staking. Blooming period is short, and foliage may become brown or tattered and susceptible to fungal diseases later in the season. As a companion plant for some vegetables, Helianthus annuus is often considered a “fourth sister,” but in a small home garden, where appearance is important, its gangly form and damage from birds and disease could make it more of an unwelcome relative.
Verbena × hybrida (garden verbena), which is winter hardy to Zone 9, grows in full sun, but can decline as heat increases or dry conditions persist. Mat-forming or bushy varieties ranging from 9–18 inches tall are usually used as annual bedding plants.
V. bonariensis (purpletop vervain), hardy to Zone 7, prefers full sun to a partially shaded location where it is more likely to contract powdery mildew. It produces flowers on slender, upright stems 3–4 feet tall from early summer until frost, and often freely self-seeds. Purpletop vervain attracts long-tongued bees, hummingbirds, and butterflies (e.g., checkerspots, eastern tiger swallowtail, great spangled fritillary, monarch, red admiral, zebra swallowtail, and various skippers).
Native perennial, V. hastata (blue vervain), hardy to Zone 3, grows in full sun. Flower spikes atop 2–4 foot stems appear midsummer to early fall and attract small bees and butterflies. Verbena spp. are host plants to the verbena moth.
This southwestern US native annual, grows 6–36 inches tall in full sun and blooms from early summer until frost. Pinching the growing tips of young plants encourages a compact form and deadheading spent flowers prolongs the bloom period. Powdery mildew can occur, especially late season, so to ensure adequate air circulation do not crowd plants. Flowers attract bees, hummingbirds, and butterflies. In 2007, the University of Kentucky conducted a study, Butterfly Feeding Preferences for Four Zinnia Cultivars, which found that Z. elegans ‘Lilliput,’ an heirloom cultivar, performed best, attracting twenty-seven species of butterflies. However, Z. x hybrida ‘Profusion’ is more disease-resistant and does not require deadheading.
Happy Pollinator Week! Happy Gardening!
Home and Garden Center Information. Clemson Cooperative Extension.
Illinois Wildflowers, © 2002-2012 by John Hilty.
Plant Directory–North Carolina State University Extension
USDA, NRCS. 2017. The PLANTS Database (18 June 2017). National Plant Data Team, Greensboro, NC 27401-4901 USA.