Honey Locust
Gleditsia triacanthos
Casts wide, high shade once it is up, and asks for very little water — but it will not tolerate anything less than full sun.
- Type
- Tree · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Sunlight
- Full sun, without compromise; this is not a tree for a shaded corner.
- Watering
- Rides out dry spells once established; water only while it is settling in.
- Feeding
- All-purpose balanced
- Frost tolerant
- Yes
- Flowering
- June
- Pruning
- Little pruning needed — take out what has to go in late winter.
- Apr–Jun Bud Break
- Jun–Oct Flowering
- Oct–Dec Leaf Fall
- Dec–Dec Winter Dormancy
- Jan–Apr Winter Dormancy
- Plant spacing
- 26 ft 3 in
- In-row spacing
- 26 ft 3 in
- Between rows
- 32 ft 10 in
- Square-foot density
- Not suited to SFG
- Root system
- Woody, shallow and far-reaching
- Working depth
- 12–24 in
- Can reach
- 4 ft down where the soil allows
- Spread
- 52–79 ft across, about 2–3× the width of the plant
Almost all of a tree’s roots are in the top two feet of soil, where the air is, and they run out well past the branch tips. The deep taproot most people picture belongs to the seedling; the tree grows out of it and spends the rest of its life spreading sideways instead.
The habit is Honey Locust’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Confirmed safe
We say a plant is safe only where a named poison-control reference names that exact species and records it as non-toxic to both cats and dogs. Most plants are on nobody’s list, and their absence here is not a judgement about them. This is a record of what those references say, not veterinary advice, and it cannot account for your own animal, the quantity eaten, or a plant treated with anything.
A separate ASPCA row, Locust (Robinia spp.), is toxic. It is a different genus and does not apply here.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Big-eyed bug Geocoris spp.Hunts Spider mites
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Green lacewing Chrysoperla carneaHunts Spider mites
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Ladybird (lady beetle) CoccinellidaeHunts Spider mites
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
- Minute pirate bug Orius spp.Hunts Spider mites
A pinhead-sized true bug that is the best natural check on thrips, and happily spears aphids, mites, and insect eggs too. It needs pollen when prey is scarce, so keep something flowering nearby.
- Predatory mites Phytoseiulus & AmblyseiusHunts Spider mites
Fast orange mites that hunt spider mites egg-by-egg, and cousins that clear thrips and fungus-gnat larvae. Sold as a biological control for greenhouses; outdoors they follow humidity — mist and mulch, don’t dust with sulfur.
- Rove beetle StaphylinidaeHunts Spider mites
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
Ornamental grasses, Sedums, Echinacea, Rudbeckia
Trees, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com