Gleditsia triacanthos
Other Name
Sweet locust
Sun Requirements
full sun
Bloom Period and Seasonal Color
Spring with small fragrant, yellow flowers, but mostly grown for its shape and open canopy and yellow fall foliage color.
Mature Height x Spread
30 to 50 feet x 50 feet
Added Benefits
attracts beneficials, fall color, native, deer resistant
Honeylocust make a perfect deciduous tree in a yard that doesn’t want heavy shade. The small green leaflets and open branch structure allows enough light to penetrate to the ground to allow lawn grass to grow. But it provides enough shade to sit under on your patio or deck. Some selections start out with light yellow leaves that turn green and then yellow again in fall. Honeylocust are tolerant to urban conditions, including air pollution and salt spray, so make great street trees. However, older selections produce brown seedpods that drop in fall and can become messy. They also may have thorns that can be dangerous when working around the tree. Newer varieties that mostly dominate the market don’t produce viable seeds or thorns.
When, Where and How to Plant
Honeylocust trees are hardy in New England. Purchase plants from your local nursery and plant from spring to early fall in well-drained, deep, fertile soil. However, honeylocust are also tolerant of various soil types. Space trees 20 to 30 feet apart.
Growing Tips
Keep trees well watered. Create a mulch ring covered with wood chips or bark mulch around individual trees planted in lawns. The mulch ring keeps the soil evenly moist and prevents trunk damage due to lawn mowers and sting trimmers. Damaged honeylocust trees are stressed and more likely to have problems with insects and diseases. Fertilize in spring with a tree plant food.
Regional Advice and Care
Honeylocust can be late to leaf out in spring, so don’t be concerned if other trees have leaves and your honeylocust does not. Prune in spring to remove small shoots along the trunk, suckers, water sprouts and competing branches. Prune out dead, diseased or broken branches any time. Honeylocust trees can have a myriad of insects and diseases attacking them. The most prolific are spider mites, gall midges and webworms. Control these with organic sprays and by keeping the trees non-stressed. Select newer varieties that don’t have troublesome thorns.
Companion Planting and Design
Honeylocust is a common street tree throughout our region and probably over planted. However, it is a great tree as a specimen in the lawn or shading a patio or deck. Some shorter growing versions make good small space trees as well.
Try These
‘Shademaster’ is the most common selection of honeylocust on the market. It grows 40 feet tall with deep green foliage and some seedpods. It also has good drought tolerance once established. ‘Suncole’ and ‘Sunburst’ are popular newer selections for their yellow-green spring foliage that turns medium green in summer and yellow again in fall. They grow 35 feet tall and don’t produce seedpods. ‘Moraine’ is an older selection that grows 40 feet tall with a wide top. It doesn’t have seedpods and has good pest resistance.
Excerpted from my book, New England Getting Started Garden Guide.
