swamp white oak

Photo: Bruce Marlin — CC BY-SA 2.5 · source

Survives zone 4 through 8

Harvest calendar

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Acorns edible after leaching out bitter tannins; a white-oak-group acorn, comparatively sweet and easy to process.

Hardiness

Zone 4–8

Habit

Tree

Edible part

Nut

Ripens

Sept–Oct

Mature size

Large tree 18–25 m — not containerable

Light

Full sun

Soil pH

Castanea 4.5–6.5 — ⚠ LIME-INTOLERANT (calcifuge, unlike other nut trees). Quercus/Fagus 5.0–6.5

Environment

Wetland

Native range

North-eastern and mid-western North America — south-western Maine west to southern Quebec, Ontario, Michigan, Wisconsin and south-eastern Minnesota, south to Iowa, Missouri, Kentucky, Tennessee and New Jersey; wet bottomland and swamp margins.

Status

Wild

Years to fruit

3–5 yrs grafted

Growth speed

30–60 cm/year — medium, slower in youth while the taproot is built.

Spacing

1200 cm (472 in) apart — about 144 m² (1550 sq ft) per plant

Leaf shape

Alternate, 12–17 cm long, with shallow rounded lobes, glossy dark green above and grey to almost white and softly downy beneath — the two-tone contrast the name bicolor records.

Root system

A strong taproot dominates the first three years, driving 60–120 cm down while the top makes only modest growth — which is why oaks resent being moved once established and why nursery stock should be planted young. Mature trees add a wide lateral network.

Fruit description

Acorns 2–3 cm long, borne singly or in pairs on distinct stalks 2–10 mm long, the cup covered in swollen scales and enclosing a third to half the nut; sweet enough to eat with modest leaching.

Propagation

⚠ White-oak-group acorns germinate in autumn, the moment they drop — they must be sown fresh and cannot be dried or stored like red oak acorns. Sow immediately in deep pots or straight into position, protected from mice; little or no cold stratification is needed.

Pollination

Wind-pollinated and monoecious — separate male catkins and tiny female flowers on the same tree, so one tree can crop. Masting: heavy years alternate with light ones, and several trees within pollen range noticeably improve set.

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.