Artemisia  'Silver Mound'

(ar-te-mee' see-ah)

Common name: Wormwood

Family: Asteraceae, Aster

Height x width: 6-48" x 12-48" depending on species

Growth rate: fast

Foliage: all except lactiflora have small, alternate; often finely divided and aromatic when bruised

Flowers: dioecious (male and female flowers on separate plants) except for lactiflora, white or yellow in early to mid summer

Hardiness: 3-5 to 8-9 varying with species

Soil: most except wet, often tolerate poor; lactiflora prefers moist

Light: sun

Pests and Problems: powdery mildew or rust on some species (seldom serious or even seen)

Landscape habit, uses: colored foliage contrasts in borders, rock gardens for clump species, cut and dried foliage, herb gardens, slopes for invasive species; stellerana tolerates salty air and water

Other interest: common name from use by Romans of this plant to treat intestinal worms, santonin from some Asiatic species still used for this purpose; Mugwort common name from use of this species in mugs to flavor beer prior to hops; various species used for many ailments include liver and kidney problems prior to 19th century; absinthium originally used to prepare absinthe--a dry bitter beverage ingredient (now produced artificially without this species)-- which was found in 19th century to contain thujone causing absinthism-- delirium and eventually death; some use of fragrance fingerprinting to differentiate cultivars by their chemical fragrance properties

Other culture: some species are invasive by roots so proper placement is crucial; some species fall over and open in centers with hot, humid weather as in the South (ludoviciana doesn't)

Propagation: division, stem or root cuttings, seeds

Species:

The following are the most common perennial species in the U.S., cold hardy to at least zone 6, and do not include ones grown primarily for herbs (dracunculus, Tarragon; vulgaris, Mugwort) or native vegetation (tridentata, now Seriphidium--sagebrush). Mugwort is an aggressive to invasive spreader, especially the variegated A. vulgaris 'Oriental Limelight'.  
 
Species zones height woody foliage habit native
*abrotanum 5-8 3-4' yes gray, very fragrant upright So. Europe
*absinthium 3-9 2-3' yes silvery-gray, fragrant upright Europe
alba 6-9 2-3' yes gray, lobed, fragrant upright Europe, N. Africa
armeniaca 5-9 2-3' no gray, wooly below upright Asia Minor
douglasiana 3-9 6-9' no green, gray below upright W. U.S.
filifolia 3-9 2-3' yes silvery upright Mexico
frigida 4-9 8-12" yes silver upright N. temperate
*lactiflora 3-8 4-6' no green upright China, India
*ludoviciana 4-9 2-4' no silvery gray beneath invasive N. America
pontica 4-9 1-2' yes light green, fragrant self sows Europe
pycnocephala 3-9 1-2' yes gray silky upright W. U.S.
schmidtiana 3-8 1-2' yes silver, finely cut mounded Japan
stelleriana 4-8 1-2' yes silver, lobed, divided spreads E. U.S., Asia


Cultivars:

The following are the most often found in U.S. commerce, with those marked * the most popular.
 
Cultivar species foliage other
'Guizho' lactiflora very dark green creamy flowers, from Blooms
'Huntington' x absinthium silver, deeply cut zones 5-7, 2-4', heat-tolerant
*'Lambrook Silver' absinthium grayish, finely cut 2-3' tall, tends to flop
*'Nana' schmidtiana silver, finely cut most popular in genus
*'Powis Castle' hybrid silver, finely cut zones 6-8, 2' tall
'Silver Bouquet' stelleriana silver low mat-forming, from UBC
*'Silver Brocade' stelleriana grayish-silver low mat-forming, from UBC
'Silver Frost' ludoviciana silver, finely cut  
*'Silver King' ludoviciana silver, cut  
*'Silver Mound': 'Nana' schmidtiana    
*'Silver Queen' ludoviciana silver, cut shorter than 'Silver King'
*'Valerie Finnis' ludoviciana silver, entire 1-2' tall, non-invasive

(cultivar photos, except 'Nana', courtesy Missouri botanical gardens plantfinder)


©Authored by Dr. Leonard Perry, Professor, University of Vermont as part of PSS123 course.

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