• GENERAL BOTANICAL CHARACTERISTICS
• RAUNKIAER LIFE FORM
• REGENERATION PROCESSES
• SITE CHARACTERISTICS
• SUCCESSIONAL STATUS
• SEASONAL DEVELOPMENT

GENERAL BOTANICAL CHARACTERISTICS:

Tall threetip sagebrush is a rounded, freely branching, native evergreen shrub that grows up to 6 feet (2 m) in height [3,38]. Leaves are long and deeply 3-cleft [5].

Wyoming threetip sagebrush is a dwarf shrub with decumbent branches. It can grow up to 59 inches (15 cm) tall, with a crown spread of 12 to 20 inches (30-50 cm) [3].

RAUNKIAER LIFE FORM:

Phanerophyte

REGENERATION PROCESSES:

Threetip sagebrush can sprout, but sprouting ability varies by geographic location which suggests ecotypic variation [2]. Both subspecies of threetip sagebrush "occasionally sprout from the roots" [9]. Tall threetip sagebrush sprouts from shallow, lateral roots or the root crown and can also layer [22]. Wyoming threetip sagebrush can also sprout from the root crown or layer [3,38].

The light seed of threetip sagebrush is wind-dispersed [49]. Both tall threetip sagebrush and Wyoming threetip sagebrush are vigorous seeders [39]. Threetip sagebrush can seed back onto disturbed sites within 5 to 10 years; density increases after treatment by herbicides [53].

Germination of threetip sagebrush is described as "moderate to rapid" [73]. In germination experiments, germination of tall threetip sagebrush increased progressively with increased stratification. Germination is greatest at approximately 60^o Fahrenheit (16^oC). Details on germination techniques for threetip sagebrush are available [36]. Threetip sagebrush seed can remain viable for 4 to 6 years in storage [54].

SITE CHARACTERISTICS:

Threetip sagebrush commonly grows on steep slopes, rocky knolls, and windswept ridges with shallow soils [6,18]. It occurs in semi-arid areas which are characterized by cold winters and warm summers [11]. Tall threetip sagebrush is especially common along river drainages [6]. Wyoming threetip sagebrush occurs on shallow, rocky soils on barren knolls surrounded by well-developed grasslands [3].

Tall threetip sagebrush grows on moderate to deep, well-drained, loamy to sandy loam soils [26]. In western Montana and Idaho, it is associated with coarse-textured sandy to stony soils [41]. In Idaho tall threetip sagebrush is often associated with fertile volcanic soils [56]. Threetip sagebrush is tolerant of dry soils [23].

The elevational range of tall threetip sagebrush in several states is as follows [10,21,69]:

3,388 to 7,084 feet (1100-2300 m) in the Intermountain Region
6,500 to 7,000 feet (1980-2130 m) in Montana
4,697 to 5,636 feet (1525-1830 m) in Utah
6,000 to 7,000 feet (1830-2130 m) in Wyoming

The elevational range of Wyoming threetip sagebrush in Wyoming is from 7,000 to 9,000 feet (2,130-2,740 m) [3].

SUCCESSIONAL STATUS:

Threetip sagebrush occurs in a number of undisturbed communities. It occurs with Idaho fescue in climax steppe communities of eastern Washington [23]. In southeastern Idaho, tall threetip sagebrush is common in late successional communities [32]. Wyoming threetip sagebrush is described as an indicator of climax in some Wyoming sagebrush communities [64]. Although tall threetip sagebrush grows in undisturbed communities, it has established on disturbed sites within 5 to 10 years. Tall threetip sagebrush increases in the absence of disturbance such as fire [2].

Tall threetip sagebrush, along with fringed sagebrush (Artemisia frigida), often replaces big sagebrush following fire in grassland communities of British Columbia [19]. Under heavy disturbance, tall threetip sagebrush stands may become dense brush fields, with tall threetip sagebrush crowding out herbaceous understory species [71].

SEASONAL DEVELOPMENT:

Threetip sagebrush begins new growth in May, young flowerheads develop in July, and flowering occurs during August and October. In Wyoming, tall threetip sagebrush flowers from June to September, with August as the most common flowering period [25]. Seed ripens in October [3].

In eastern Idaho phenological development of threetip sagebrush is as follows [8,72]:

 Dates for various stages in 1965           Average dates for 1941-1947
----------------------------------------------------------------------------
leaf growth started       Apr 25           April
twig growth started       May 25           mid-June
flowerbuds evident        Jun 20           ------               
flowerstalk growth        Jul 20           ------   
    stopped
first bloom               Sept 1           ------
full bloom                ------           mid-Sept
blooming over             Sept 20          ------  
seed ripe                 Oct  12          mid-Oct
seed disseminated         Nov  05          ------
previous year's leaves
     begin to drop        Aug  05          ------
previous year's leaves    Sep  02          ------
     off

  
leaf growth     twig growth     flower buds    1st       full
starts          starts          visible        bloom     bloom

4/20             6/25           6/17           9/15      9/18

bloom           seed            leaves      
over            ripe            drying

9/30            10/14           7/30 

Wyoming threetip sagebrush blooms in late August and September; the seeds ripen in October [3].

Related categories for SPECIES: Artemisia tripartita | Threetip Sagebrush