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Pear variety

Bosc

Also known as Beurre Bosc, Kaiser

The short answer

Bosc requires 500–600 chill hours[1] and grows in USDA zones 5–9[1]. It needs a pollination partner[2].

Growing facts

Bosc growing facts
Chill requirement500–600 chill hours[1] (nursery figure)
HardinessUSDA zones 5–9[1] (nursery figure)
PollinationNeeds a pollination partner, bloom group 4[2]
Harvest windowSeptember[1]
Years to bearing4–6 years (typical for pears)[3]
USDA pomological watercolor of Bosc pear
Pyrus communis: BoscUSDA pomological watercolor, Ellen Isham Schutt, 1910 · USDA Pomological Watercolor Collection

Plate provenance[4]

Pollination partners

Bosc blooms in group 4. The closest bloom-time matches make the most reliable partners:

Show 1 more compatible variety

Notes

  • Not self-fruitful; pollenized by Bartlett or other pear.[1]
  • A late bloomer, along with Comice, that may be more fruitful where late spring frost is a risk.[5]
  • One of the popular commercial varieties that are very susceptible to fire blight.[6]

A year with your Bosc

When the work happens for a pear in USDA zone 7, anchored to typical frost dates.

Months for pruning, thinning, spray-timing windows, and harvest for Pear in zone 7
TaskJFMAMJJASOND
Prune———————————
Thin——————————
Spray timing———————
Harvest—————————
Care——————————

See the full month-by-month pear calendar for zone 7 →

Can I grow Bosc where I live?

Check the verdict for a few regions, or your exact ZIP:

Growing a Bosc? Get its care calendar for your exact ZIP code, with email reminders.

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Questions

How many chill hours does Bosc need?
Bosc needs 500–600 chill hours.
What hardiness zones suit Bosc?
Bosc grows in USDA zones 5–9.
Is Bosc self-pollinating?
No — Bosc needs a compatible pollination partner nearby.

Sources

  1. [1] Dave Wilson Nursery. Bosc pear — variety specifications — accessed July 2026
  2. [2] Washington State University Tree Fruit. Pollination — Pear (WSU Tree Fruit) — accessed July 2026
  3. [3] Iowa State University Extension and Outreach. How soon will a newly planted fruit tree begin to bear fruit? (Yard and Garden FAQ) — accessed July 2026
  4. [4] USDA National Agricultural Library. USDA Pomological Watercolor Collection (Rare and Special Collections, 1886-1942) — accessed July 2026
  5. [5] Burnt Ridge Nursery. European pear pollination chart — accessed July 2026
  6. [6] Virginia Cooperative Extension (Virginia Tech). Growing Pears in Virginia (VCE 422-017) — accessed July 2026