Cool-season grass dominant in zones 3–7. Dormancy: goes dormant (tan/brown) when temps exceed 32°C for 2+ weeks, or when drought-stressed. Recovery: greens up rapidly in cool, moist conditions. Overseeding window: early fall (soil 50–65°F). Spring green-up: consistent temps >10°C for 14 days. Mow at 2.5–4 in (never remove more than 1/3 at once). Summer stress protocol: raise mowing height to 4 in; water deeply 1x/week (1 in); allow partial dormancy in severe heat rather than forcing growth. Fall prep: aerate + overseed + fertilize (Oct in zone 5–6, Sep in zone 4). Fertilize schedule: heavy fall feed (1 lb N/1000 sqft), light spring feed to avoid disease. Spreads by rhizomes — self-repairs bare spots over time.

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