Restoring Western Ranges and Wildlands
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E. Durant McArthur Richard Stevens Chapter 21 Composite Shrubs The sunflower family (Compositae or Asteraceae) is the largest family of flowering plants. Its many species occur around the world as annual and perennial herbs and as shrubs and trees (Benson 1957; Cronquist 1968; Wagenitz 1977). Three shrubby genera of the family—sagebrush (Artemisia), rabbitbrush (Chrysothamnus), and matchbrush (Gutierrezia)—make plants of this family among the most common and important plants of the Intermountain area (McArthur and others 1979a; table 1). Shrubs of these genera provide critically needed ground cover on arid Western ranges, are important sources of browse for domes- tic livestock and big game, and serve as cover and forage for many wildlife species. A number of sagebrush and rabbitbrush species are important as cover for small birds, game birds, and mam- mals, and as browse plants for big game animals, especially on winter and early spring ranges. Some species also provide forage for livestock (sheep and cattle). Horsebrush and matchbrush also contribute more forage than is generally believed; however, both plants may, under certain conditions, be harmful to domestic livestock (Benson and Darrow 1945; Johnson 1974a; McArthur and others 1979a) and cause allergies in humans (Lewis and Elvin-Lewis 1977; Rodriguez and others 1976). USDA Forest Service Gen. Tech. Rep. RMRS-GTR-136. 2004 493 Chapter 21 Composite Shrubs Chapter Contents by Species General sagebrush culture ................................................................................................................. 496 Artemisia abrotanum (oldman wormwood) ....................................................................................... 497 Artemisia arbuscula (low sagebrush ................................................................................................. 499 Artemisia bigelovii (Bigelow sagebrush) ........................................................................................... 500 Artemisia cana (silver sagebrush) ..................................................................................................... 502 Artemisia filifolia (sandsage or oldman sage) .................................................................................. 504 Artemisia frigida (fringed sage) ......................................................................................................... 505 Artemisia longiloba (alkali sagebrush).............................................................................................. 506 Artemisia nova (black sagebrush) ...................................................................................................... 508 Artemisia pygmaea (pygmy sagebrush) ............................................................................................. 509 Artemisia rigida (stiff or scabland sagebrush).................................................................................. 510 Artemisia spinescens (budsage).......................................................................................................... 511 Artemisia tridentata (big sagebrush) ................................................................................................. 513 Artemisia tripartita (threetip sagebrush) ......................................................................................... 521 Other sagebrushes .............................................................................................................................. 522 General rabbitbrush culture .............................................................................................................. 522 Chrysothamnus depressus (dwarf rabbitbrush) ................................................................................ 524 Chrysothamnus linifolius (spreading rabbitbrush) ............................................................................ 524 Chrysothamnus nauseosus (rubber rabbitbrush).............................................................................. 525 Chrysothamnus parryi (Parry rabbitbrush) ...................................................................................... 529 Chrysothamnus vaseyi (Vasey rabbitbrush) ..................................................................................... 531 Chrysothamnus viscidiflorus (low rabbitbrush) ............................................................................... 531 Other rabbitbrushes ........................................................................................................................... 533 Other composite shrubs...................................................................................................................... 534 Haplopappus species (goldenweed) ............................................................................................. 534 Tetradymia species (horsebrush) ................................................................................................ 534 Gutierrezia species (matchbrush or snakeweed) ........................................................................ 534 Lepidospartum latisquamatum (scalebroom) ............................................................................. 534 Various forms of sagebrush and rabbitbrush may ranges include big sagebrush (A. tridentata), black also be directly seeded or transplanted for landscaping, sagebrush (A. nova), threetip sagebrush (A. tripartita), stabilizing, and beautifying disturbed landscapes and low sagebrush (A. arbuscula), budsage (A. spinescens), may have potential for supplying industrial chemi- fringed sage (A. frigida), sand sage (A. filifolia), cals. Young wildings of both sagebrush and rabbit- early sagebrush (A. longiloba), rubber rabbitbrush brush transplant easily. Usually within 3 to 7 years, (C. nauseosus), low rabbitbrush (C. viscidiflorus), direct seeded or transplanted plants are established Greene’s rabbitbrush (C. greenei), spreading rabbit- sufficiently to reproduce naturally from seed. Both brush (C. linifolius), and Parry’s rabbitbrush (C. parryi). establish well when properly aerially or drill seeded Some of these species, for example, threetip sagebrush (McArthur and others 1974; Plummer 1977; Plummer and Parry’s rabbitbrush, are usually found on ranges and others 1968). at higher elevations than the others. In this chapter, we prefer to limit the term sage- Virtually all of these species include an array of brush to members of the subgenus Tridentatae ecotypes. Some are large taxonomic units that include (McArthur 1979; McArthur and others 1981). Other several subspecies (big sagebrush, rubber rabbitbrush, woody members of the genus Artemisia then become low rabbitbrush, and Parry’s rabbitbrush) (McArthur “sage” or “wormwood.” However, in the broad sense in and others 1979a). These shrubs, especially under this chapter, use of sagebrush alone may refer to any conditions of heavy grazing, may form closed stands. woody, native North American Artemisia species. However, in many locations they mix with grasses and Sagebrush and rabbitbrush species that are espe- forbs. Big sagebrush often occurs with the grasses, cially important on low elevation Intermountain area bluebunch wheatgrass, western wheatgrass, the 494 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-136. 2004 Chapter 21 Composite Shrubs Table 1—Important Composite shrubs of the Intermountain burning, tillage, or mechanical or chemical treatment. area. Many of these observations were made on rangelands where the plant community was judged to be in near- Common name Scientific name climax condition. Some areas, in fact, had no evidence a of use or disturbance of any kind except by native Oldman wormwood Artemisia abrotanum fauna. On all study sites supporting subspecies of big Low sagebrush Artemisia arbuscula sagebrush, annual growth rings of the largest stems Bigelow sagebrush Artemisia bigelovii were counted to determine the age of the plants and Silver sagebrush Artemisia cana to establish the length of time during which there had Sand or oldman sage Artemisia filifolia been no fires. The oldest plants found were about 120 Fringed sage Artemisia frigida years old, and several locations supported plants at Longleaf sage Artemisia longifolia least 100 years old. Many of the older plants had split Alkali sagebrush Artemisia longiloba and nearly decayed stems on which the growth rings Black sagebrush Artemisia nova could not be accurately counted; so some plants may have been even older. With few exceptions, the oldest Birdsfoot sage Artemisia pedifida (not necessarily the largest) plants grew on stony or Pygmy sagebrush Artemisia pygmaea gravelly soils, and were of the Wyoming big sagebrush Stiff or scabland sagebrush Artemisia rigida subspecies. On disturbed relic areas, subspecies of big Budsage Artemisia spinescens sagebrush typically grew in open stands with indi- Big sagebrush Artemisia tridentata vidual plants or small clumps of plants uniformly Threetip sagebrush Artemisia tripartita distributed. Where it grew, big sagebrush made up five Alkali rabbitbrush Chrysothamnus albidus to 20 percent of the total annual production on the Dwarf rabbitbrush Chrysothamnus depressus study site. Spreading rabbitbrush Chrysothamnus linifolius Woody Artemisia, called wormwood in North Africa Greene’s rabbitbrush Chrysothamnus greenei and Eurasia, are principal components of the steppes Rubber rabbitbrush Chrysothamnus nauseosus of those regions. There (Larin 1956), as in North Parry rabbitbrush Chrysothamnus parryi America