Ephemeral plant

Trillium grandiflorum in the foreground and the smaller Thalictrum thalictroides in the background are both spring ephemerals of North American deciduous forests.

An ephemeral plant is one marked by short life cycles, usually six to eight weeks. The word ephemeral means transitory or quickly fading. In regards to plants, it refers to several distinct growth strategies. The first, spring ephemeral, refers to perennial plants that die back to their underground parts after a short growth and reproduction phase each spring when excess light is available. Another strategy is that of weedy ephemerals, which are very short lived weedy annuals whose entire life cycle takes less than a growing season. Desert ephemerals are plants which are adapted to take advantage of the short wet periods in arid climates.

Spring ephemerals

Spring ephemeral describes a life habit of perennial woodland wildflowers which develop aerial parts (i.e. stems, leaves, and flowers) of the plant early each spring and then quickly bloom, go to seed and then quickly die back to its underground parts (i.e. roots, rhizomes, and bulbs) for the remainder of the year. This strategy is very common in herbaceous communities of deciduous forests as it allows small herbaceous plants to take advantage of the high amount of sunlight reaching the forest floor prior to the leaf-out of woody plants. Examples include: spring beauties, trilliums, and harbinger of spring.

Spring ephemerals include:

• Claytonia sp. (Spring Beauty)
• Dicentra canadensis (Squirrel Corn)
• Dicentra cucullaria (Dutchman's Breeches)
• Dicentra eximia (Turkey Corn)
• Dodecatheon sp. (Shootingstar)
• Erigenia bulbosa (Harbinger of Spring)
• Erythronium americanum (Yellow Trout Lilly)
• Hepatica nobilis (Hepatica)
• Houstonia caerulea (Azure Bluet)
• Iris cristata (Dwarf Crested Iris)
• Jeffersonia diphylla (Twinleaf)
• Mertensia virginica (Virginia Bluebells)
• Sanguinaria canadensis (Bloodroot)
• Stylophorum diphyllum (Celandine poppy, wood poppy)
• Thalictrum thalictroides (Rue Anemone)
• Tiarella cordifolia (Foamflower)
• Trillium erectum (Red Trillium/Wake Robin)
• Trillium grandiflorum (Common/White Trillium/Wake Robin)
• Trillium luteum (Yellow Trillium/Wake Robin)
• Trillium ovatum (Western Trillium/Wake Robin)

Weedy ephemerals

Alternatively ephemeral also refers to annual plants that complete their life-cycle in much less than one year; when plants are classified simply as ephemeral plants this is often what is meant. Allowing more than one generation of the plant to set seed in one growing season. These plants rarely have any commercial use, and can be invasive weeds. Examples include: Cardamine hirsuta and Cannabis ruderalis.

Desert ephemerals

This normally bare desert in Namaqualand, Goegap Nature Reserve in South Africa has a proliferation of flowers and desert ephemerals during the brief spring wet season.

Desert ephemerals, such as the Arabidopsis thaliana, are plants which are adapted to take advantage of the very short favourable seasons in deserts. Annual plants in deserts may use the weedy ephemeral strategy to survive in the desert environment. These species survive the dry seasons through seed dormancy. Alternatively, some perennial desert plants may die back to their underground parts and become dormant when there is not enough water available.