Shademaster honeylocust

Sun

Full sun; tolerates light shade but develops a better crown in an open position.

Water

Water regularly while establishing. Once established, tolerates drought, though prolonged dry weather can cause early leaf drop.

Soil

Adaptable to clay, loam and sandy soils, including alkaline soils, provided drainage is adequate. Avoid persistently waterlogged ground.

Height

40-60 ft (12-18 m)

Spread

35-50 ft (11-15 m)

Flowers

Small, inconspicuous greenish-yellow flowers in late spring to early summer.

Foliage

Fern-like leaves made up of many small green leaflets; turns golden yellow in autumn and drops relatively early.

Growth

Fast when young, slowing with maturity.

Care needed

Medium

• Drought tolerant
• Cold hardy
• Wildlife

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

Difficulty

Moderate

Toughness

Very tough

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

1. Planting day

   7 ft (2 m)

2. After 1 year

   9 ft (2.7 m)

3. After 2 years

   11 ft (3.3 m)

4. After 3 years

   13 ft (4 m)

5. After 5 years

   17 ft (5.3 m)

About 20 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

Native to

the US and Canada

Invasive in

Australia

Growth rate

Moderate

• Plant with the root flare at soil level, allowing enough space for the mature crown and spreading roots.
• Water deeply during dry spells for the first two or three growing seasons, moistening the root zone rather than watering a little each day.
• Spread 2-3 in (5-8 cm) of organic mulch over the root area, keeping it clear of the trunk.
• Do not feed routinely; use a soil test before applying fertiliser, especially beside a fertilised lawn.
• Stake only if the root ball moves in wind, use flexible ties, and remove supports after establishment.
• Remove shoots from below the graft promptly, as rootstock growth may carry thorns.

Pruning. Prune in late winter during dry weather, removing dead, damaged or crossing branches and developing one main leader while the tree is young. Avoid topping and large cuts; use a qualified arborist for mature-tree work.

Late winter

Check branch structure and make light formative cuts before growth begins.

Spring

Plant where soil is workable, water thoroughly and mulch without covering the root flare.

Late spring

Inspect new leaves for distorted growth, pod-like swellings or honeydew from feeding insects.

Summer

Deep-water young trees during dry spells and check that ties are not rubbing or tightening.

Early autumn

Check for dead twigs, bark damage and shoots emerging below the graft.

Late autumn

Plant in mild regions while soil remains workable; gather any pods and seedlings if they occur.

• Use as a lawn specimen where its broad canopy can develop without repeated size reduction.
• Place beside a patio to provide filtered summer shade rather than a dense, dark canopy.
• Underplant with shade-tolerant perennials and spring bulbs, allowing for increasing root competition as the tree matures.
• Repeat along a spacious drive or boundary for a loose avenue with yellow autumn colour.

Garden styles it suits: Modern, Mid-century modern, Traditional, Grand estate, Family-friendly and Autumn colour.

Plant it with: Epimedium, Hardy geranium, Solomon's seal, Christmas fern, Daffodils and Snowdrops.

Wildlife: The canopy offers perching and nesting cover, and the foliage supports some insects. Flowers may attract pollinating insects, but this largely podless cultivar supplies little seed food compared with fertile honeylocust trees.

• Honeylocust plant bugs can distort and discolour new foliage. Keep young trees adequately watered; established trees usually tolerate the damage, so avoid routine insecticide spraying.
• Honeylocust pod gall midge causes swollen, pod-like leaflets, sometimes with twig dieback. Remove affected tips on small trees and seek local advice if damage is repeatedly severe.
• Cankers and branch dieback are more likely on stressed or injured trees. Protect bark from mowers, water during prolonged drought and have dead branches removed in dry weather.
• Poor branch unions can split as the crown enlarges. Arrange formative pruning while young and have weak forks assessed by an arborist rather than topping the tree.

Honeylocust is not known to be toxic to people, cats, dogs or horses. This is different from black locust, which is poisonous. Pods and seeds are not a reason to encourage pets or children to eat garden material; hard seeds can be a choking hazard, and any thorny rootstock shoots can cause puncture wounds.

Where it spreads. The species spreads aggressively and is regulated in parts of eastern Australia, notably Queensland and New South Wales, and is invasive in South Africa. 'Shademaster' is generally largely podless, but occasional pods and thorny rootstock growth are possible; do not assume the cultivar is exempt from local restrictions.

• Black locust (Robinia pseudoacacia)

  Has larger, rounded leaflets, hanging clusters of fragrant white flowers and often paired spines at the leaf bases. Its bark, seeds and other parts are poisonous, unlike honeylocust.

• Japanese pagoda tree (Styphnolobium japonicum)

  Has larger, pointed leaflets and conspicuous creamy-white flower clusters in late summer, followed by bead-like pods.

• Wild honeylocust (Gleditsia triacanthos)

  Wild trees often have large branched thorns on trunks and branches and long, dark, twisted seed pods. 'Shademaster' normally lacks thorns and produces few or no pods.

Gleditsia honours botanist Johann Gottlieb Gleditsch, triacanthos means three-spined, and honeylocust refers to the sweet pulp inside the species' pods.

Propagation. Propagated commercially by budding or grafting onto honeylocust rootstock. Seedlings do not reliably retain 'Shademaster' characteristics; buy a correctly labelled, grafted tree.

Accepted botanical name

Gleditsia triacanthos

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky and Louisiana.

Measured

Soil pH 4.8 to 8. Average height 1675 cm.

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