Walnut & Heartnut Pollination Chart
Walnuts and heartnuts are wind-pollinated and each tree tends to shed pollen before or after its own female flowers are ready, so plant two or more trees. Seedling bundles usually include both flowering types.
Good match (same bloom group)Partial match (one group apart)Blooms too far apartPoor or unreliable pollen (triploid, pollen-sterile or disputed)Won't work (same clone or genetically incompatible)Same variety
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Walnut & Heartnut bloom groups at a glance
4 Mid
- Buartblack (estimated)
- Purvis English Walnut Seedling (estimated)
- Purvis Hardy English (estimated)
- Ultra Northern English (estimated)
5 Mid-Late
- Black (estimated)
- Rhodes Heartnut Seedling (estimated)
How to use this chart
Find the variety you want to pollenize in the left column, then read across. Each column is a pollen source. Dark green means the two bloom in the same group, light green means they're one group apart and still overlap. Names with a * have an estimated bloom group.
Bloom groups run 1 (very early) to 7 (very late) within one kind of fruit only. An apple in group 4 and a plum in group 4 don't bloom at the same time. Two varieties within one group of each other overlap enough to pollenize, as long as the pollen is good and they aren't the same clone. Plant partners within about 100 feet so the bees work both.
Where our groups come from: published bloom records first (for apples, measured king-bloom dates from the Apple Biodiversity Collection in Nova Scotia, checked against multi-year nursery and extension groupings), then sourced facts like a sport's parent, then our best estimate from origin and related varieties. Montana springs shift everything earlier or later, but the order holds.