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Thursday, October 3, 2019

Night Bloomers

Berlandier's Trumpets
Many night blooming flowers have white or light-colored blossoms, a strong fragrance (although not always to human noses), and open by night and close by day.  These flowers are extremely important nectar sources for pollinators, and they are attracted to these flowers’ nectar mainly by scent.  Two of our best night blooming native plants are Berlandier’s Trumpets (Acleisanthes obtusa) and Jimsonweed (Datura wrightii).

Closeup of Berlandier's Trumpets
Also known as Vine Four O’Clock, Berlandier’s Trumpets is an upright perennial herb or climbing vine up to 6 feet long, easily controlled but often clambering over shrubs and small trees if left unchecked.  Its opposite, bright green leaves are triangular shaped, about 1.5 inches long, with slightly wavy edges.  But it is its white to light pink trumpet-shaped flowers, about 2 inches long, that bloom from April to December, producing a fragrant scent when open at night.  Berlandier’s Trumpet does well in full sun to part shade, is drought tolerant, and easy to grow and maintain.

Jimsonweed
Jimsonweed is a 3 to 6 foot tall stoutly branched herb, with alternate, coarse, large gray-green leaves that are broad at the base and pointed at the tip.  While its foliage is often described as rank-smelling, its flowers are sweetly fragrant white trumpets, up to 8 inches long, sometimes tinged with purple at the edges.  It blooms from May to November, and its flowers open in evening and close during the heat of the day.  

Jimsonweed Bloom

The fruit of this plant is a very distinctive spiny, globular capsule up to 1.5 inches in diameter, which opens fully when ripe.  Jimsonweed has several other common names such as Sacred Thorn-apple, Angel Trumpet, Devil’s Trumpet, and Sacred Datura. Some of these names refer to its use as a hallucinogen in Native American ceremonies, but it is important to note that all parts of this plant are toxic to humans.

Jimsonweed Fruit
Both of these native night blooming species attract several species of Sphinx moths (sometimes known as hawkmoths or hummingbird moths) as well as other pollinating insects such as long-tongued bees, butterflies, and hummingbirds.  But it is the Jimsonweed that has mastered the art of mutualism, with its partner the Carolina Sphinx.  

Carolina Sphinx
While it is common for this plant to benefit from its relationship with the Carolina Sphinx (Manduca sexta) in the form of pollination, in turn it provides nectar for the adult moth and is the host plant for the moth’s caterpillars.  These large caterpillars (known to gardeners as ‘tomato hornworms’), consume many or all of the Jimsonweed’s leaves. But the plant is prepared for the attack, storing resources in its massive root enabling it to produce more leaves for the next generation of caterpillars.  In effect, Jimsonweed grows its own pollinators to ensure its reproductive success!