Gray Sheoak Casuarina glauca
Gray Sheoak is an introduced perennial tree, found in Hawaii, the lower 48 states, and the Pacific Basin. It grows to 60 ft and blooms Apr in part shade – shade, with brown fruit.
More about this plant
Casuarina glauca, commonly known as swamp she-oak, swamp buloke, swamp she-oak, marsh sheoak, grey she-oak, native pine, or guman by the Gadigal people, is a species of flowering plant that is endemic to eastern Australia. It is a dioecious tree that often forms root suckers and has fissured and scaly bark, spreading or drooping branchlets, the leaves reduced to scales in whorls of 12 to 20, the fruit 9–18 mm (0.35–0.71 in) long containing winged seeds (samaras) 3.5–5.0 mm (0.14–0.20 in) long. Wikipedia →
Gray Sheoak is flagged invasive in the U.S. These natives fill a similar niche — same growth habit, bloom season, height, and region — so you keep the look and feed local wildlife instead of spreading a problem.
Growing & care
USDA PLANTS · TRY- Sun
- Part shade – shade
- Soil & moisture
- Medium moisture
- Soil pH
- 6.5–7.5
- Fertility need
- Low
- Adapts to
- Coarse (sandy), Medium (loam)
- Hardiness
- USDA zone 9+
- Height
- 60 ft
- Mature width
- ~ 36 ft wide DERIVED derived estimate — open-grown crown allometry (height × growth-form ratio); not a measurement
- Spacing
- 8–12 ft apart from USDA planting density
- Spread
- Rapid
- Growth rate
- Rapid
- Growth form
- Single stem
- Lifespan
- Perennial · short-lived
- Foliage
- Evergreen scale-leaved · fine texture
- Active growth
- Spring through autumn
- Fruit
- Brown
- Propagate by
- Seed, Cuttings, Bare root, Container
- Seed starting
- No stratification needed
- Seeds ripen
- Summer – Autumn seed-collection / harvest window
- In the trade
- Routinely available
- Resprouts if cut
- Yes regrows after top-kill
Sow timing keys off your local last- and first-frost dates.
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts Documented caterpillar host
Recorded feeding on Casuarina in North America, including:
Wildlife & visitors 1 bird
Open records of who else uses Gray Sheoak — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 1 bird species (fruit, seed, browse):
Related plants
More Casuarina → 
How we know this (4) 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.
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
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.
For woody plants that have a height but no measured crown, we estimate width = height × a crown-to-height ratio fit for that plant’s form (conifers narrower than broadleaf trees, shrubs widest), calibrated on our measured open-grown crowns and capped at the largest one ever measured. A measured crown always wins; herbaceous plants get nothing (no anchor).
Honest limits: A coarse class-median estimate for garden-scale spacing, not a measurement; woody single/multi-stem forms only.
Sources for this entry (32) 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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