Artemisia ludoviciana gnaphalodes
Aster family (Asteraceae)
Description: This perennial plant becomes about 2-3' tall when it is mature, branching occasionally in the upper half. The stems are covered in a dense mat of short white hairs. The alternate leaves are up to 3½" long and 1" across. They are usually oblanceolate, narrowly ovate, or linear. The lower leaves may have a few lobes or coarse teeth towards their tips, while the upper leaves have smooth margins. Like the stems, the leaves have a dense mat of short white hairs, especially on the lower surface. This variety of White Sage has dense white hairs on the upper surface of the leaves as well, except for the oldest leaves toward the bottom of the plant. The leaves are sessile against the stem, or have short petioles. Some of the upper stems terminate in elongated spikes or narrow racemes of compound flowers. Each flowerhead is only 1/8" (3 mm.) across, and contains numerous whitish green disk florets that are inconspicuous. The blooming period is late summer to early fall, and lasts about 2-3 weeks. There is no floral scent, although the foliage of this plant is quite aromatic. Pollination is by wind, rather than insects. The tiny seeds are without tufts of hair, but are small enough to be distributed by the wind. The root system is rhizomatous, and can form a dense mat of roots near the surface of the ground. As a result, this plant has a strong tendency to form clonal colonies that exclude other plants.
Cultivation: The preference is full sun and dry conditions. Poor soil containing hardpan clay, rocky material, or sand is actually preferred as a medium for growth, as this reduces competition from other plants. The foliage is very attractive and doesn't have significant problems with disease. This plant can spread aggressively in some situations.
Range & Habitat: White Sage is occasional in northern and western Illinois, but rare or absent in other parts of the state (see Distribution Map). Some authorities think this plant is native to Illinois (e.g., Britton & Brown), while others believe it is adventive from the west (e.g., Mohlenbrock). It is usually found along railroads and roadsides, and sometimes in dry upland areas of prairies. Cultivated forms of this plant can be found in flower gardens because of the attractive foliage. If this plant is native, Illinois would be at the eastern boundary of its distribution.
Faunal Associations: The flowers don't attract insects because they are wind-pollinated. White Sage has the potential to cause allergies in humans because of this pollen, but this species isn't very common within the state. Several grasshopper species feed on the foliage of White Sage (see Grasshopper Table), including an uncommon oligolectic grasshopper, Hypochlora alba (Cudweed Grasshopper), which often feeds hides in the foliage during the day. Other insect feeders include Ophraella artemisiae (Leaf Beetle sp.), Macrosiphoniella ludovicianae (Aphid sp.), and the larvae of Phaneta argenticostana (Tortricid Moth sp.); the moth larvae feed on the seedheads. Mammalian herbivores don't consume this plant because the aromatic foliage has a bitter taste. The seeds are too small to be of much interest to birds.
Photographic Location: The photographs were taken at Meadowbrook Park in Urbana, Illinois, where a small colony of plants was located in a restored prairie. The plants were not in bloom.
Comments: This variety of White Sage has striking foliage. The typical variety, Artemisia ludoviciana ludoviciana, has greener foliage with fewer white hairs. The leaves of this latter variety are supposed to be broader and more likely to have lobes or serrated margins toward the leaf tips. However, the hairiness and shape of the leaves can be rather variable for this species, regardless of the variety. Other Artemisia spp. have foliage that is more green and pinnately lobed. A few species, such as the introduced Artemisia vulgaris (Mugwort), have silvery hairs on the lower surface of the leaves, but their upper surface is predominantly green.