Blue palo verde

Sun

Full sun; flowering and branch structure are best in an open position.

Water

Low once established. Water young trees deeply, allowing the soil to dry between waterings; established trees benefit from occasional deep watering during prolonged hot drought.

Soil

Well-drained sandy, gravelly or loamy soil, including alkaline soil. Avoid persistently wet ground and poorly drained clay.

Height

20-30 ft (6-9 m)

Spread

20-30 ft (6-9 m)

Flowers

Spring; masses of bright yellow flowers, sometimes followed by scattered flowers after rain.

Foliage

Small, blue-green, twice-divided leaves with tiny leaflets; drought- and cold-deciduous. Smooth blue-green trunks and branches remain conspicuous when leafless.

Growth

Moderate to fast when young, especially with irrigation.

Care needed

Low

• Pollinators
• Drought tolerant
• Heat tolerant
• Wildlife
• Low allergen

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

Difficulty

Hard

Toughness

Needs looking after

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

1. Planting day

   7 ft (2 m)

2. After 1 year

   8 ft (2.3 m)

3. After 2 years

   9 ft (2.7 m)

4. After 3 years

   10 ft (3 m)

5. After 5 years

   12 ft (3.7 m)

About 16 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

Safe

Growth rate

Fast

• Plant where the mature canopy can spread without repeated cutting back, away from paths where thorns could catch passers-by.
• Water deeply through the root zone while establishing, then gradually lengthen the interval between waterings.
• Keep lawn irrigation and frequent shallow watering away from the trunk.
• Do not routinely fertilise; excessive feeding and watering encourage weak, overly rapid growth.
• Keep mulch clear of the trunk and leave the root flare exposed.
• Stake only if the root ball is unstable, and remove supports once roots provide firm anchorage.

Pruning. Prune lightly in dry weather in early summer, after the main flowering display, removing dead, crossing or poorly attached branches. Develop well-spaced main limbs while young; avoid topping or suddenly exposing shaded bark to intense sun.

Late winter

Inspect for frost damage and broken branches; wait until growth resumes before deciding which frost-damaged shoots are dead.

Spring

Plant once severe frost risk has passed, water thoroughly and check drainage.

Spring

Allow flowering to finish before carrying out nonessential pruning.

Early summer

Make light structural pruning cuts and remove dead or rubbing branches.

Summer

Check soil moisture below the surface and water deeply only when the root zone has dried.

Autumn

Reduce irrigation as temperatures fall and remove accumulated pods from paving if needed.

• Use as a specimen tree in a gravel garden, where blue-green bark contrasts with stone and yellow flowers.
• Provide light, seasonal shade over a dry garden seating area, keeping thorny branches clear of access routes.
• Combine with agaves, yuccas and low desert shrubs for a layered southwestern planting.
• Plant in a broad, open courtyard where its spreading silhouette can develop without clipping.

Garden styles it suits: Desert modern, Southwestern, Desert / xeriscape, Dry gravel garden, Architectural minimal and Wildlife garden.

Plant it with: Red yucca, Desert marigold, Brittlebush, Desert globe mallow, Banana yucca and Parry's agave.

Wildlife: Flowers provide pollen and nectar for bees and other insects. Seeds feed some birds and small mammals, while the canopy offers shelter and nesting sites.

• Root and crown rot in wet soil: improve drainage, keep the trunk dry and stop frequent irrigation; badly affected trees may need removal.
• Palo verde root borer in the southwestern United States: maintain sensible watering and avoid root injury; routine surface insecticide treatments do not reliably control larvae underground.
• Mistletoe: have small infestations removed with the affected branch where practical; seek an arborist's advice for large limbs or extensive infection.
• Split limbs and storm breakage: establish well-spaced branches when young and avoid heavy irrigation, overfeeding and topping.

Not known to be toxic to people, cats, dogs or horses, though species-specific veterinary information is limited. Thorns can cause puncture wounds, and hard seeds or pods can be choking hazards.

• Foothill palo verde (Parkinsonia microphylla)

  Usually smaller and more densely branched, with yellow-green rather than distinctly blue-green bark, smaller leaves and paler yellow flowers.

• Mexican palo verde (Parkinsonia aculeata)

  Has conspicuously long, slender leaf axes carrying many tiny leaflets, giving a finer, drooping appearance. It is a major invasive weed in parts of Australia and should not be confused with blue palo verde.

• Desert Museum palo verde (Parkinsonia 'Desert Museum')

  This hybrid is thornless, generally has larger flowers and often blooms over a longer period; blue palo verde normally has thorns.

Palo verde means 'green stick' in Spanish, referring to the photosynthetic bark; Parkinsonia honours English botanist John Parkinson, and florida means 'floriferous'.

Propagation. Grow from seed. Carefully nick the hard seed coat without cutting into the seed, then soak in warm water for 12-24 hours and sow in a free-draining mix in warm conditions. Transplant young seedlings before their roots become crowded.

Accepted botanical name

Parkinsonia florida

Native range

Arizona, California, Mexico Northeast, Mexico Northwest and Nevada.

Measured

Average height 1000 cm.

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