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

GENERAL BOTANICAL CHARACTERISTICS:

Hairy grama is a densely tufted, warm-season, short-lived, perennial, native shortgrass. Culms are numerous, 8 to 16 inches (20-40 cm) tall and hairy [4,19,61]. In the northern part of its range and in areas with sufficient precipitation, hairy grama may form a continuous groundcover [75]; while in the drier, southern portions, the grasses are distinctly clumped [61].

Hairy grama has shallow, fibrous roots, which may allow it to take advantage better of intermittent, sparse precipitation during the warm growing season [4,56]. Biomass production of hairy grama positively correlates with growing season (April-August) precipitation [56]. At the Los Alamos National Laboratory in north-central New Mexico, the rooting depth of hairy grama averaged 41 inches (103 cm), with a range from 18 to 55 inches (46-137 cm) [24].

Hairy grama resists drought [67]. In Nebraska laboratory studies to assess the ability of prairie grasses to withstand drought, hairy grama was the 3rd most resistant species, after blue grama and buffalograss. Hairy grama suffered very little mortality under high temperatures, low water, and simulated hot winds (soil and atmospheric drought) [50].

RAUNKIAER LIFE FORM:

Hemicryptophyte

REGENERATION PROCESSES:

Hairy grama usually reproduces vegetatively [65]. The plants are probably self-sterile [61].

In an evaluation of a Nebraska sandhills prairie seedbank, hairy grama was a prominent part of the aboveground species composition (13%), yet was rare or absent from seedbank germination trials [55]. In this study, the only seedlings to emerge were from seed chilled for 14 days at 37 to 41°Fahrenheit (3-5°C). Walther and Sexton [77] harvested seed from a Texas prairie dominated by hairy grama, little bluestem, and slim tridens (Tridens muticus). Despite its dominance in the stand, hairy grama seeds contributed only 1.9% of the seed weight of the harvested seeds. Germination rate for hairy grama after 14 days was only 3.8 %. A germination viability study of hairy grama after 20 years' uncontrolled storage resulted in 0% germination in Globe, Arizona [70].

SITE CHARACTERISTICS:

Hairy grama is common in open plains, in partially shaded openings in woods and brush, on well-drained, usually rocky soils [32]. Hairy grama survives in some difficult sites, including dry sandy or sandy-loam soils, [19] and rocky hills [35]. The plant grows predominantly on rocky sites in Kansas [72]. Hairy grama does better in thin rocky soils in New Mexico than on better soils, where it gives way to blue grama [12].

In southeastern Arizona, hairy grama rarely dominates but is widespread. The plant occurs in all major habitats except for floodplains and washes, mostly on silty soils with much exposed rock [8]. Hairy grama prefers coarser soils than does blue grama [41]. On the Edwards Plateau, Texas, hairy grama is usually associated with stony-loamy clay soils [75].

Throughout its range, hairy grama is common in ridge sites with thin soils and droughty characteristics [56]. Although the plant is a subdominant or codominant on many habitat types, these harsh sites are one of the few types on which hairy grama dominates. In a southern Nebraska loess hills mixed-grass prairie, hairy grama occurs most commonly on limy and lowland sites, and less often on silty sites. Limy sites are calcareous uplands with 7-31% slope, and shallow, silt loam soils. These sites are quite dry, since soils have low water capacity and drainage is rapid. In contrast, the lowland sites are characterized by steep slopes but relatively high water holding capacity [60].

Hairy grama grows from 165 to 990 feet (50- 300m) in the Great Plains [32], and from 1,000 to 6,500 feet (300-1970 m) throughout the Southwest [42]. In the Guadalupe Mountains National Park in Texas, hairy grama is common between 5500 and 6,000 feet (1650-1800 m), on soils derived from eroded sandstone [15,51]. In Arizona and New Mexico, hairy grama is most commonly found from 4,000 to 6,500 feet (1212-1969 m), but occasionally lower [36,59].

SUCCESSIONAL STATUS:

In the Trans-Pecos region of Texas, hairy grama is a seral species on the feather bluestem-little bluestem-sideoats grama habitat type [14].

In North Dakota, hairy grama is a seral species of the bluestem tallgrass prairie [29].

SEASONAL DEVELOPMENT:

In Nebraska, growth starts in early to mid-July [67]. Anthesis in eastern Nebraska occurs from the 4th week in July through the 3rd week in August [65].

In Texas, flowering occurs from May to mid-July [61].

Related categories for SPECIES: Bouteloua hirsuta | Hairy Grama