Gleditsia tricanthos var. inermis - Thornless Honeylocust
Family: Caesalpiniaceae

Hear the scientific name

Gleditsia triacanthosvar. inermis is an urban tolerant tree, excellent for filtered summer shade and its majestic winter outline.

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  form Form

-large deciduous tree

-maturing at 60' tall x 40' wide

-upright oval growth habit, developing a rounded or flat-topped crown with age

-rapid growth rate, often with a second flush of growth in summer

foliage Foliage

-alternate, with pinnately and bipinnately compound leaves often occurring on the same tree

-petiole base swollen, attaching to the young stems at every zig and zag

-leaflets very small, results in light shade (filtered or dappled shade) that permits grass to grow underneath the tree

-autumn color normally yellowish green, but yellow or golden in good years

Flowers

-polygamo-dioecious (male and female flowers on separate trees, but all trees have perfect [male + female] flowers as well)

-pendulous male catkins and smaller female inflorescences are not particularly showy and often lost in the expanding foliage

-golden-green, occurring in late May and early June

Fruit
fruit

-most cultivars have little fruit set

-however, some do, being up to 1.5' long twisting pods, changing from yellow green to dark brown-red to purplish at maturity, containing many hard seeds

-fruits abscising in late autumn (the common name comes from the sweetness of the fleshy pod) and causing quite a litter problem when in abundance

-the thorny native species usually has tremendous fruit set

Twig
twig

-zigzag and brown-red, somewhat streaked, with no terminal bud

trunk Trunk

-often straight for 5-15', then dividing into several large branches

-bark is smooth, tan-olive to gray-olive, and heavily lenticeled when young, but soon becoming deeply fissured, forming flared gray plates with an orange interior bark, then becoming somewhat scaly with age

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Culture

-full sun

-prefers moist, deep, acid to alkaline soils but is very adaptable and quite urban tolerant (especially to heat, drought, high soil pH, soil compaction, flooding, and salt spray)

-several cosmetic problems (leaf spot, spider mites), but also some serious disease (cankers) and pest (webworms and borers) problems

-abundant availability, including many cultivars, in B&B form

distribution map

Hardiness

-zones 4 to 9

Origin

-native to floodplains of the Eastern and Southern U.S.

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Assets

-fine-textured foliage

-very urban tolerant

-filtered shade

-rapid growth and establishment

-minimal leaf litter, making autumn cleanup unnecessary

-wet site tolerant

Liabilities

-surface roots often become a major mowing problem with age

-locust borers and webworms are significant pests

-fruit pods (if present) may present a fruit litter problem

Function

-shade or specimen tree

-often used, along with Green Ash (Fraxinus pennsylvanica), for tightly confined, high urban stress areas such as parking lot islands and downtown street tree squares, where they eventually get too large and surface roots become a problem

Texture

-fine texture in foliage and bold when bare

-open density in foliage and when bare

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Varieties and Cultivars - Search OSU PlantFacts for additional plants in this species

Alternates

-urban tolerant shade trees with rapid growth and establishment (Acer x freemanii, Fraxinus pennsylvanica, Platanus occidentalis, Populus deltoides, Quercus shumardii, etc.)

-trees with filtered shade (Amelanchier, Betula species, Malus, Robinia pseudoacacia, etc.)

-shade trees for wet or dry sites (Alnus glutinosa, Fraxinus pennsylvanica, Nyssa sylvatica, Platanus occidentalis, Salix alba, etc.)

 


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