Kieffer Pear
Pollination & Compatibility Guide
Kieffer pear pollination guide: European × Asian hybrid vigour, Bloom Group 4 timing, fire blight resistance, and culinary processing.
Kieffer is Self-Sterile (Needs 1 Diploid Partner)
Widely reported to set a useful crop planted alone in the southern USA, but the crop is heavier and better seeded with a partner, so plan one. It is an interspecific hybrid with Asian pear ancestry and blooms towards the early end of the European pear range — Moonglow, Harrow Delight and other early-to-mid cultivars overlap it better than late ones. Bartlett is very likely a direct parent and should not be the chosen pollinizer. Kieffer needs at least one compatible pollinizer from bloom group 3–5 to set a reliable crop. It is often sold as self-fertile, and it will set a reduced crop alone in warm, long-season regions — the southern USA, where it is grown in near-solid blocks; set is materially heavier and better-seeded with a partner — but that is climate-dependent, not genetic, so plan a pollinizer.
- Chromosome Ploidy
- Diploid (2n)
- Required Companions
- 1 Diploid Partner
- Bloom Group
- Group 4 (Late-Spring)
- Harvest Timing
- Late (+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 3 to 5 provides matching blossom overlap.
Compatible Pollination Partners (16)
| Cultivar | Bloom Group | Overlap Type | Harvest | Primary Uses | Interactive Test |
|---|---|---|---|---|---|
| Group 4 | Full Overlap | Late Concurrent (±0d) | Fresh Eating, Cooking | Test Cross | |
| Group 4 | Full Overlap | Late Concurrent (±0d) | Fresh Eating | Test Cross | |
| Group 4 | Full Overlap | Mid Concurrent (±0d) | Fresh Eating, Storage | Test Cross | |
| Group 4 | Full Overlap | Late ±21d delta | Fresh Eating, Storage | Test Cross | |
| Group 3 | Full Overlap | Late Concurrent (±0d) | Fresh Eating, Baking | Test Cross | |
| Group 3 | Full Overlap | Late Concurrent (±0d) | Fresh Eating | Test Cross | |
| Group 3 | Full Overlap | Mid Concurrent (±0d) | Fresh Eating, Storage | Test Cross | |
| Group 3 | Full Overlap | Late Concurrent (±0d) | Fresh Eating | Test Cross | |
| Group 3 | Full Overlap | Late ±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 | Late ±21d delta | Fresh Eating, Canning | Test Cross | |
| Group 3 | Full Overlap | Mid ±21d delta | Fresh Eating, Canning | Test Cross | |
| Group 3 | Full Overlap | Early ±28d delta | Fresh Eating, Canning | Test Cross | |
| Group 3 | Full Overlap | Early ±39d delta | Fresh Eating | Test Cross |
Incompatible Varieties & Exclusions (4)
These pear varieties overlap in flowering time with Kieffer but cannot fertilise it due to non-viable pollen (male-sterile diploids), direct parentage exclusions, or shared incompatibility alleles.
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.
Gourmet produces no viable pollen, so it cannot serve as a pollinizer.
Magness produces no viable pollen, so it cannot serve as a pollinizer.
Warren produces no viable pollen, so it cannot serve as a pollinizer.
Pomological Assessment: Interspecific Hybrid Vigour, Heavy Cropping & Culinary Use
Originating in Roxborough, Pennsylvania, in the 1860s as an accidental hybrid between European Bartlett and an Asian sand pear (Pyrus pyrifolia), Kieffer is renowned for its remarkable vigor, rugged constitution, and heavy annual crops. The fruit is large, oval-pyriform, with thick greenish-yellow skin.
Kieffer is a diploid hybrid that blooms in Bloom Group 4 (late mid-season). While it frequently sets partial crops without cross-pollination due to natural hybrid vigor, interplanting with compatible late-blooming diploids like Anjou, Comice, or Potomac significantly enhances fruit size, yield stability, and tree balance.
Trees are upright, rapid-growing, and exceptionally resilient, tolerating drought, heat, and poor soil drainage. Heavy crop loads require sturdy limb development or summer support to prevent branch splitting under bumper autumn yields. Growers in hot, humid climates value Kieffer for its ability to produce consistent annual yields with minimal management inputs, making it a staple variety for farm-gate sales, homestead orchards, and commercial canning processors.
Key Orchard Considerations for Kieffer
Extremely vigorous and adaptable; thrives on standard Pyrus communis seedlings as well as OHxF 87/97. Tolerates heavy clay, poorly drained ground, and drought conditions where other cultivars struggle.
Exceptional resistance to fire blight, enabling productive cultivation in warm, humid regions of the American South and Midwest where European varieties succumb to bacterial pressure.
Harvests late in autumn. The coarse, firm flesh with prominent grit cells softens moderately when stored; widely processed for canning, preserves, baking, and hard perry cider production.
Take Kieffer 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 Kieffer 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.