Turf
Perennial ryegrass (winter overseed)
Lolium perenne · Poaceae
Also called: Perennial rye, English ryegrass, Winter overseed ryegrass
Perennial ryegrass (winter overseed) (Lolium perenne) is a moderate-water turf well suited to Tucson and the low desert. It thrives in full sun to part shade. Expect inconspicuous blooms N/A in turf use.
Perennial ryegrass (winter overseed) at a glance
- Water use
- Moderate (established)
- Sun
- Full sun to part shade
- Mature size
- Turf height 1.5-2.5 in mowed
- Growth rate
- Fast (germinates in 5-10 days)
- Bloom
- Inconspicuous, N/A in turf use (mowed; would seed in late spring/summer if unmowed)
- Cold hardiness
- Cool-season; thrives in Tucson's mild fall/winter/spring and dies out in summer heat above ~90-95 F, which is by design for overseeding.
- Soil
- Prefers well-drained, fertile soil; adapts to typical lawn soils.
- Native range
- Europe, temperate Asia, and North Africa.
- Best used as
- Winter overseeding of dormant bermuda lawns for year-round green, Quick-establishing turf
- Wildlife
- Minimal; functional turf.
- Toxicity
- Non-toxic; can host endophytes but turf-type seed sold for overseeding is endophyte-free and safe.
How to grow Perennial ryegrass (winter overseed) in Tucson & the low desert
Watering
Cool-season grass used for winter overseeding: keep the seedbed lightly moist with 2-4 short irrigations per day during germination (first 2-3 weeks), then transition to deeper, less frequent watering of about 1 in/week through the cool months. Needs less water than summer bermuda but must not dry out while establishing.
Fertilizer & nutrients
Apply a starter (phosphorus-containing) fertilizer at overseeding for germination, then nitrogen roughly every 4-6 weeks through winter (about 0.5-1 lb N per 1,000 sq ft) to keep it green; ease off in spring to favor bermuda transition.
Pruning & care
First mow when it reaches about 2-2.5 in (roughly 10-14 days after seeding); maintain at 1.5-2.5 in through winter. Stop fertilizing and stress it in late spring to help the bermuda outcompete it.
Notes
In Tucson, sow over dormant bermuda in mid-October (when nighttime lows reach the mid-60s F), scalping and dethatching the bermuda first. Provides green winter color, then naturally dies out in late spring/early summer as heat returns and the bermuda resumes growth. Overseeding increases winter water and maintenance and can weaken the underlying bermuda — AMWUA discourages it where water conservation is the priority.
Sources: University of Arizona Cooperative Extension (Overseeding / Lawn publications); AMWUA; Arizona Department of Water Resources