Warren Pear
Pollination & Compatibility Guide
Warren pear pollination guide: male-sterile diploid classification, pollinizer partner rules, high fire blight resistance, and orchard care.
Warren is Male-Sterile (Needs 1 Partner · Cannot Donate Pollen)
Do not rely on Warren as the pollinizer for another cultivar — its pollen is of uncertain viability. Plant it as a main cultivar with a separate, known-good donor of overlapping bloom (Moonglow, Harrow Sweet, Blake's Pride). Warren needs at least one compatible pollinizer from bloom group 2–4 to set a reliable crop.
- Chromosome Ploidy
- Diploid · Male-Sterile
- Required Companions
- 1 Diploid Partner
- Bloom Group
- Group 3 (Mid-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 (23)
| Cultivar | Bloom Group | Overlap Type | Harvest | Primary Uses | Interactive Test |
|---|---|---|---|---|---|
| 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 | Mid ±28d 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 | |
| Group 3 | Full Overlap | Mid ±42d delta | Fresh Eating | Test Cross | |
| Group 4 | Full Overlap | Late Concurrent (±0d) | Fresh Eating, Cooking | Test Cross | |
| Group 4 | Full Overlap | Late Concurrent (±0d) | Fresh Eating | Test Cross |
Incompatible Varieties & Exclusions (3)
These pear varieties overlap in flowering time with Warren but cannot fertilise it due to non-viable pollen (male-sterile diploids), direct parentage exclusions, or shared incompatibility alleles.
Gourmet produces no viable pollen, so it cannot serve as a pollinizer.
Luscious produces no viable pollen, so it cannot serve as a pollinizer.
Magness produces no viable pollen, so it cannot serve as a pollinizer.
Pomological Assessment: Pollen Non-Viability, Flavour Profile & Blight Resistance
Discovered in Mississippi by fruit breeder T.O. Warren and believed to share parentage with Magness (Seckel × Comice), Warren is revered for its extraordinary eating quality. Its pale green fruit develops a silky, completely grit-free texture and an intensely sweet, floral flavour that matches Comice in blind sensory evaluations.
In commercial practice, Warren is managed as a male-sterile diploid. Although genetically diploid, its pollen viability is extremely low and inconsistent, rendering it unreliable as a pollinizer for companion rows. Warren requires a dependable Bloom Group 3 diploid partner—such as Bartlett, Bosc, Conference, or Harrow Sweet—to donate viable pollen, and any companions in the block must have their own independent pollinizer.
The tree is naturally vigorous and upright, requiring limb spreaders or branch tying to initiate horizontal fruiting spurs. Once established, Warren produces moderate, steady annual crops of exquisite dessert fruit that command premium prices in direct-to-consumer markets. Growers in the American South prize Warren for its ability to produce world-class dessert pears in warm, humid districts with low chill hour accumulation.
Key Orchard Considerations for Warren
Grafts cleanly to OHxF 87 and OHxF 97 rootstocks. Naturally vigorous with an upright branching habit; benefits from branch spreading or horizontal trellis training to encourage precocious spur development.
Exhibits near-complete immunity to fire blight in humid southern and mid-Atlantic districts where European pears usually perish. Resistant to trunk cankers and leaf spot.
Picks mid-season (early to mid-September). Requires 2–4 weeks of cold storage conditioning at 0–2°C followed by several days at ambient room temperature to achieve peak buttery texture.
Take Warren 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 Warren 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.