Gambel oak

Sun

Full sun to light shade; the densest growth develops in sun.

Water

Water regularly while establishing; drought-tolerant once rooted. Established plants generally need supplemental water only during prolonged drought.

Soil

Well-drained sandy, gravelly or loamy soil, including limestone-derived soils. Tolerates moderately acidic to alkaline conditions but dislikes waterlogged ground.

Height

15-30 ft (4.6-9.1 m), occasionally taller on favourable sites

Spread

15-25 ft (4.6-7.6 m) per crown; suckering colonies can become much wider

Flowers

Spring, as leaves emerge; yellow-green male catkins and tiny, inconspicuous female flowers.

Foliage

Rounded leaves with deep, blunt lobes; dark green above and paler, often hairy beneath. Autumn colour ranges from yellow to orange and rusty brown; some dead leaves remain through winter.

Growth

Slow to moderate

Care needed

Low

• Drought tolerant
• Cold hardy
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2 m)

2. After 1 year

   7 ft (2.2 m)

3. After 2 years

   8 ft (2.4 m)

4. After 3 years

   8 ft (2.6 m)

5. After 5 years

   10 ft (2.9 m)

About 26 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Native to

the US

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Slow

• Plant young, container-grown trees in well-drained ground; established oaks are difficult to transplant.
• Water deeply through the first two growing seasons, allowing the soil surface to dry between waterings.
• Spread a 2-3 in (5-8 cm) layer of mulch over the root area, keeping it clear of the trunk.
• Avoid routine fertiliser and frequent lawn irrigation around established trees.
• Remove unwanted root suckers while small, or allow space for a natural colony.

Pruning. Prune in the dormant season, removing dead, damaged or crossing branches and selecting a main stem if you want a tree rather than a thicket. Avoid heavy crown reduction and unnecessary large cuts.

Late winter

Prune damaged or crossing branches and make any light structural cuts.

Spring

Plant young trees where winters are severe, and begin deep watering as growth starts.

Late spring

Refresh mulch and remove unwanted suckers before they become woody.

Summer

Check soil moisture around young trees; water deeply rather than giving frequent light sprinkles.

Autumn

Leave some fallen leaves beneath the canopy for wildlife, keeping paths and the trunk base clear.

Early autumn

Collect ripe, fallen acorns and sow promptly if you want to propagate it.

• Use as a small shade tree in a dry garden, allowing room for its broad crown.
• Plant in informal groups with native grasses for an open woodland effect.
• Allow suckering growth to form a wildlife thicket along a spacious boundary.
• Combine with drought-tolerant shrubs and perennials on well-drained slopes.

Garden styles it suits: Southwestern, Mountain lodge, Woodland, Wildlife garden, Desert / xeriscape and Rewilded.

Plant it with: Little bluestem, Blue grama, Sideoats grama, Mountain mahogany, Serviceberry and Firecracker penstemon.

Wildlife: Acorns feed squirrels, jays, wild turkeys and other wildlife. The foliage supports many moth and butterfly caterpillars, while dense colonies provide cover and nesting sites. Deer browse young growth.

• Root rot and decline in wet soil: improve drainage before planting and keep established trees away from frequently irrigated lawns.
• Powdery mildew: improve airflow and avoid overhead watering; light infections usually need no treatment.
• Leaf and twig galls: usually cosmetic and best left alone; have persistent twig dieback assessed before removing affected growth.
• Unwanted suckering: cut shoots at their point of origin while small; do not apply systemic herbicide to suckers connected to a tree you want to keep.

Leaves, buds and acorns contain tannins and can poison horses and other livestock, sometimes causing fatal kidney damage when enough is eaten. Dogs and cats can also become ill after eating them; acorns present an additional choking or intestinal-blockage risk. Raw acorns and substantial amounts of foliage are unsafe for people to eat; traditional acorn preparation requires thorough tannin removal.

Where it spreads. Spreads vigorously by root suckers and can form extensive colonies within its native range in the southwestern United States and northern Mexico. This is native thicket formation rather than evidence of introduced invasiveness; allow space or manage suckers.

• Bur oak (Quercus macrocarpa)

  Bur oak has conspicuously fringed acorn cups and often much larger leaves with a narrowed middle section; Gambel oak has smaller acorns with unfringed, scaly cups.

• Arizona white oak (Quercus arizonica)

  Arizona white oak usually retains leathery, shallowly toothed or nearly entire leaves through winter. Gambel oak is deciduous and normally has deeply rounded leaf lobes; hybrids can blur these differences.

The species name gambelii honours William Gambel, the American naturalist who collected plants in the western United States.

Propagation. Sow fresh, ripe acorns promptly in deep pots protected from rodents; they lose viability if allowed to dry and may begin rooting soon after falling. Seed-grown plants vary, and acorns collected near other compatible oaks may produce hybrids.

Accepted botanical name

Quercus gambelii

In the US and Canada

Native in the lower 48 states.

Native range

Arizona, Colorado, Mexico Northeast, Mexico Northwest, Nevada, New Mexico, Oklahoma, Texas, Utah and Wyoming.

Measured

Average height 1300 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.