Culture Notes
The tree has no particular soil preferences and is useful in dry or alkaline areas, although its native habitat is along stream banks. Although a legume, nitrogen-fixing bacteria (rhizobia) have not been associated with the root system. It tolerates high soil salt concentrations originating from de-icing salt applications better than many other plants. It tolerates compacted, poorly aerated soil and flooding for a period of time once it is well established and does well in confined soil spaces. However, if soils are too wet during the establishment period then trunks can rot at the base leading to decline and death of the tree.
Honeylocust adapts well as a city street tree and is tolerant to small planting pits in concrete. It is susceptible to breakage in ice storms. Trees cast light shade under the canopy making it easier to grow turf under the tree than under other trees with a denser canopy.
The species and cultivars grow fine in zones 8 and 9 in the western US, not in the southeast US. The tree has grown poorly in the hottest regions of the southeast (east of the Appalachian mountains) unless supplied with supplemental irrigation or planted on a moist site. Trees tried in the deep south might have been from northern races which could account for their poor growth - perhaps we should make an effort to try the southern races for the southern landscapes. On the other hand, the trees may simply not be adapted to this area - make note that Honeylocust is not native east of the Appalachian Mountains.
Unfortunately, it has been over-planted in some areas and insect problems are beginning to catch up with Honeylocust, including the cultivars. The species and cultivars grow fine in zones 8 and 9 in the western US, not in the southeast US.
Thyronectria canker infection can be minimized by maintaining a layer of mulch or groundcover beneath the canopy. Bare soil under the canopy increases soil temperature in summer and allows for greater temperature fluctuations in winter leading to increased stress on the tree. This makes trees more susceptible to canker infection according to the latest research. Wood is considered ring porous.
Pests, Diseases and Damaging Agents
Pests: Mimosa webworm has become a serious pest on Honeylocust in some communities where it defoliates trees each year in mid summer. Boring insects may be largely prevented by keeping trees healthy with regular fertilization. The combination of plant bug and leafhopper feeding causes the leaves to drop. Pod gall midge causes unusual reddish galls at the tips of the branches - this cultivar is especially susceptible. Leaflets become pod-like. Spider mites cause an autumn like yellowing of the leaves. Leafminers and bagworm can also be a problem. Aphid infestations can be troublesome.
Diseases: Canker causing fungi or bacteria attack branches and trunks causing dieback of parts or the entire tree. Thyronectria canker is more common on trees that have experienced drought after planting; this cultivar is especially susceptible. There is a leaf spot that may be a problem. Powdery mildew may cause a white coating on the leaves but is seldom serious.
This plant is sensitive to damage from ozone air pollution. Damage can occur in urban or rural areas because ozone can travel long distances away from where it is formed. Typical symptoms on deciduous trees are a flecking or stippling only on the upper side of the foliage between large veins. The small spots or flecks are white, tan or orange-red. Spots or flecks from one-eighth to one-quarter inch long appear on needles of sensitive conifers. Yellow bands that girdle the needle may form, eventually causing the tips of the needles to die and/or needles to drop from the plant. If you suspect ozone is causing damage on this plant, locate White Pines (Pinus strobus) in the area to see if they are damaged. White Pines are very sensitive to ozone damage and can serve as indicators of the presence of ozone in concentrations high enough to cause plant damage.Â
The fruit is dry, elongated and of a pod-like shape.