Native Spring Ephemerals: Evolved for Success

by Elaine Mills, Extension Master Gardener
Photos © Elaine Mills unless otherwise noted

Many of our favorite spring wildflowers (including Virginia bluebells, Dutchman’s breeches, trout lily, and the trilliums) are ephemerals: plants that bloom, set seed, and die back for the year within a relatively short period of time. For example, the pleated leaves of mayapple (Podophyllum peltatum) begin to emerge and unfurl in late March to early April. Its white blossoms attract insects for pollination beginning in late April in the Mid-Atlantic area, and lemon-shaped fruit forms in mid-May. By late June, its foliage is already browning and withering. Over the millennia, these native species have developed a number of strategies to increase their chances of surviving and reproducing.

As geophytes (perennial plants with underground storage structures referred to generically as bulbs), ephemerals pass through a “warm-cold-warm” sequence in their annual life cycle. In the spring, they send carbohydrates from photosynthesis to their bulbs to fuel later development. After a period of summer dormancy, cooler fall temperatures cue the plants to produce compact leaves, stems, and flower buds within the bulbs, giving them a head start on spring growth before they emerge from the soil.

In natural settings, ephemerals are found in the understory of deciduous forests where they emerge from the protective leaf litter and grow in the early spring sunlight. The presence of fully formed chloroplasts in their leaves and the activation of their photosynthetic proteins at low temperatures permit them to photosynthesize at a high rate in order to grow quickly before trees in the canopy layer begin to leaf out.

Native ephemerals are small plants, usually less than 18 inches tall. With their shallow root systems, they can take advantage of the thawing of the upper layer of the forest floor to absorb water and nutrients before larger plants with deeper roots begin growth. Extensive symbiotic arrangements between plant roots and networks of fungi, referred to as mycorrhizal associations, greatly facilitate the uptake of these resources.

Various structural adaptations allow spring ephemerals to withstand chilly nighttime temperatures. For example, the flowers of bloodroot (Sanguinaria canadensis) emerge enfolded by their palmate leaves. The warm air trapped by the leaves protects the flowers from frost. The flower stems (scapes) of round-lobed hepatica (Hepatica americana) are densely covered in silky hairs that insulate them from both cold temperatures and drying winds. The flowers of several species, such as spring beauty (Claytonia virginica), close at night and on cloudy days to protect their pollen from cold and rain.

Although some species can self-pollinate when closed to ensure that reproduction occurs when the weather is unfavorable for pollinators, close relationships with insects are generally vital to the success of ephemeral plants. Some species, such as bloodroot, do not produce nectar, instead relying on attracting early-emerging native bees to their pollen since wind speed for pollination is greatly reduced in wooded areas. Other plants, such as large-flowered bellwort (Uvularia grandiflora), have nodding flowers that draw native insects cruising along the forest floor for nectar and pollen, including bumble bees, mason bees, sweat bees, and mining bees.

Still other ephemerals have mutualistic relationships with specific pollinators. For example, bumble bee queens are a perfect match for early-blooming Dutchman’s breeches. They are able to fly in cool weather, they have the strength to pry open the plant’s inner hinged petals, and they have tongues long enough to reach the nectar inside the blossoms. Flowers such as trout lily and spring beauty are visited by oligolectic native bees that have a narrow, specialized pollen preference for provisioning their nests from just a few or even a single host plant.

Finally, many native ephemerals rely on myrmecochory, a mutualistic process with ants as a means of dispersing their seeds. Ants are attracted to seeds of pollinated flowers that are covered by lipid- and protein-rich food bodies called elaiosomes. They carry the seeds to their nests and feed these fleshy structures to their larvae, later taking the seed to their waste disposal area from which new plants can grow.

For more information on spring ephemerals native to the Mid-Atlantic and their strategies for success, see the recording of a presentation on “Native Spring Ephemerals” in our Master Gardener Virtual Classroom.

Resources

“Badass Spring Ephemerals.” In Defense of Plants, April 6, 2015.

 “Myrmecochory: How Ants Shape Plant Communities.” Julie Michaelson, Xerxes Society, 11 July 2024.

“The Role of Temperature in the Growth and Flowering of Geophytes.” Nadezda V. Khodorova and Michèle Boitel-Conti. Plants (Basel). 2013 Nov 2; 2(4):669-711.