

Thickspike Wheatgrass Elymus lanceolatus
Thickspike Wheatgrass is a perennial grass native to Alaska, Canada, and the lower 48 states. It grows to 2.3 ft and blooms Jun – Aug.
More about this plant
Elymus lanceolatus is a species of grass known by the common names thickspike wheatgrass and streamside wheatgrass. It is native to North America, where it is widespread and abundant in much of Canada and the western and central United States. There are two subspecies, subsp. lanceolatus occurring throughout the species' range and subsp. psammophilus occurring in the Great Lakes region. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 4 derived from its U.S. range
- Height
- 2.3 ft
- Lifespan
- Perennial
- Foliage
- Broadleaf
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~31 caterpillar species
Elymus supports ~31 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a strong genus.
Recorded feeding on Elymus in North America, including:
+ 8 more species → ↑ show fewer
Across 42 U.S. vegetation-survey plots that recorded Thickspike Wheatgrass, these catalog species turned up most often in the same plot — a real field co-occurrence signal, not a planting prescription.
How we know this (2) Methods & honest limits
We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.
Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
Sources for this entry (22) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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