Bartlett (Williams' Bon Chrétien) Pear
Pollination & Compatibility Guide
Bartlett (Williams' Bon Chrétien) pear pollination guide: diploid compatibility, Seckel exclusion rule, Quince graft incompatibility, and orchard care.
Bartlett (Williams) is Self-Sterile (Needs 1 Diploid Partner)
Bartlett (Williams' Bon Chrétien) needs at least one compatible pollinizer from bloom group 2–4 to set a reliable crop. It is often sold as self-fertile, and it will set a reduced crop alone in hot climates only — California's Sacramento Valley, Australia's Goulburn Valley, South Africa. Reliably self-infertile in cool maritime climates — but that is climate-dependent, not genetic, so plan a pollinizer.
- Chromosome Ploidy
- Diploid (2n)
- Required Companions
- 1 Diploid Partner
- Bloom Group
- Group 3 (Early-Spring)
- Harvest Timing
- Mid (-14d from Conference)
Flowering Period & Overlap Window
Pear flowering periods are compressed into numbered bloom groups (1 through 4). Cross-pollination requires overlapping blossom timing between genetically compatible cultivars, with Asian pears flowering 7–14 days ahead of mid-season European varieties.
Any compatible diploid pear flowering within Group 2 to 4 provides matching blossom overlap.
Compatible Pollination Partners (15)
| Cultivar | Bloom Group | Overlap Type | Harvest | Primary Uses | Interactive Test |
|---|---|---|---|---|---|
| Group 3 | Full Overlap | Early Concurrent (±0d) | Fresh Eating, Canning | Test Cross | |
| Group 3 | Full Overlap | Late ±7d delta | Fresh Eating, Canning | Test Cross | |
| Group 3 | Full Overlap | Mid ±7d delta | Fresh Eating, Canning | Test Cross | |
| Group 3 | Full Overlap | Mid ±14d delta | Fresh Eating, Cooking | Test Cross | |
| Group 3 | Full Overlap | Late ±14d delta | Fresh Eating, Cooking | Test Cross | |
| Group 3 | Full Overlap | Mid ±14d delta | Fresh Eating | Test Cross | |
| Group 3 | Full Overlap | Late ±28d delta | Fresh Eating, Baking | Test Cross | |
| Group 3 | Full Overlap | Late ±28d delta | Fresh Eating | Test Cross | |
| Group 2 | Full Overlap | Mid Concurrent (±0d) | Fresh Eating, Canning | Test Cross | |
| Group 2 | Full Overlap | Early ±6d delta | Canning, Jelly | Test Cross | |
| Group 4 | Full Overlap | Late ±7d delta | Fresh Eating, Storage | Test Cross | |
| Group 2 | Full Overlap | Early ±7d delta | Fresh Eating, Canning | Test Cross | |
| Group 4 | Full Overlap | Late ±28d delta | Fresh Eating, Cooking | Test Cross | |
| Group 4 | Full Overlap | Late ±28d delta | Fresh Eating | Test Cross | |
| Group 4 | Full Overlap | Mid ±28d delta | Fresh Eating, Storage | Test Cross |
Incompatible Varieties & Exclusions (11)
These pear varieties overlap in flowering time with Bartlett (Williams) but cannot fertilise it due to non-viable pollen (male-sterile diploids), direct parentage exclusions, or shared incompatibility alleles.
A direct parent (Williams' Bon Chrétien × Beurré Superfin) — roughly half the pollen is non-functional, so it is not a reliable partner.
Gourmet produces no viable pollen, so it cannot serve as a pollinizer.
A direct parent ((Old Home × Early Sweet) × Bartlett) — roughly half the pollen is non-functional, so it is not a reliable partner.
A direct parent (Bartlett × (Old Home × Early Sweet)) — roughly half the pollen is non-functional, so it is not a reliable partner.
A direct parent (Bartlett × Doyenné du Comice) — roughly half the pollen is non-functional, so it is not a reliable partner.
A direct parent (Chinese Sand Pear (P. pyrifolia) × Bartlett (presumed pollen parent)) — roughly half the pollen is non-functional, so it is not a reliable partner.
Luscious produces no viable pollen, so it cannot serve as a pollinizer.
Magness produces no viable pollen, so it cannot serve as a pollinizer.
Cross-incompatible in both directions.
A direct parent (Max Red Bartlett × US 56112-146) — roughly half the pollen is non-functional, so it is not a reliable partner.
Warren produces no viable pollen, so it cannot serve as a pollinizer.
Pomological Assessment: Commercial Benchmark, Incompatibility Rules & Culture
Discovered in Berkshire in the 1760s as Williams' Bon Chrétien and popularized across North America as Bartlett, this variety is the global reference standard for both fresh dessert pears and commercial canning. The flesh is fine-grained, exceedingly melting, and intensely aromatic with a distinctive musky sweetness that defines classic pear flavour.
Bartlett is a diploid cultivar requiring cross-pollination for commercial yields. While it can produce seedless fruit parthenocarpically in hot, semi-arid summer valleys, commercial plantings in temperate regions require cross-pollination. A crucial pomological exclusion must be observed: Bartlett cannot cross-pollinate Seckel (and vice versa) due to shared genetic incompatibility. Reliable partners include Beurré Bosc, Anjou, Conference, and Moonglow flowering in Bloom Group 3.
The tree is moderately vigorous with an upright, spreading growth habit that requires careful branch training to develop sturdy horizontal scaffold limbs. Heavy annual fruit set frequently leads to small fruit sizes unless systematically thinned within four weeks of petal fall. Regular dormant pruning to renew aged fruiting spurs ensures sustained yields of top-grade fruit.
Key Orchard Considerations for Bartlett (Williams)
Bartlett has direct graft incompatibility with Quince rootstocks (Quince A and Quince C); grafts made directly will fail or snap at the graft union under crop load. Commercial plantings must use an interstem (such as Beurré Hardy or Old Home) or be propagated on clonal Pyrus rootstocks like OHxF 87 or OHxF 97.
Bartlett is highly susceptible to fire blight (Erwinia amylovora). Blossom strikes rapidly travel into structural scaffolds and rootstock suckers, requiring rigorous blossom blight risk monitoring and swift sanitation pruning.
Harvested mid-season when skin transitions from deep green to light green and flesh firmness reads 6.8–7.7 kg/cm² (15–17 lbs). Bartlett ripens quickly off the tree at 18–21°C, developing a bright golden-yellow skin and melting texture.
Take Bartlett (Williams) from Planning to Planting
Use Kropigo's free browser tools to model your block density, tree counts, and pollinizer rows, then maintain permanent orchard records row by row.
Pollination Checker
Check Bartlett (Williams) against supported cultivars with compatible flowering and pollination data.
Commercial Block Planner
Calculate high-density tree spacing, row geometry, and establishment costs.
Block Record Keeping
Track pruning, chemical thinning, and harvest tallies block by block from the orchard.