“Locusts” refers to several species of trees which bear seed pods resembling legumes.
The plants under consideration belong to the family Fabaceae, or legumes and peas, and are indigenous to North America. Some species of locust trees are further divided into the genera Gleditsia and Robinia. Hence, locusts can be either trees or shrubs.
In North America, the most popular locust species are black locust and honey locust.
Within this article, you can find comprehensive information in regards to the different species of locust trees, their applications, and associated planting techniques.
There was also an underlying mystique about locust trees as well as other flowers and trees that stem from the belief in secret meanings of flowers.
Honey Locust Trees (gleditsia triacanthos)
Within the category of landscaping trees, honey locust is common and for good reason. It is known as Кледитсии triacanthос; hard-growing honey locust, or thorny honey locust.
Like black locusts, honey locusts (Gleditsia triacanthos) belong to the Gleditsia genus. They are also referred to as thorny honeylocust or thorny locust.
As a species endemic to central North America, the honey locust is found in river valleys and shed leaves seasonally.
The honey locust is a rugged tree species that is tolerant of wind storms, ice, foot traffic, and pollution. It grows fast too—reaching 20 feet in the first decade and eventually scaling to 70 feet.
They have stunning gray-brown barks and petite oval leaves that turn yellow during autumn. Most varieties also bear pods that contain edible pulp as fruits.
Using the scientific name gleditsia triacanthos, you can search and obtain images to enjoy their landscaping potential.
What Does A Locust Tree Look Like?
How Many Types of Locust Trees Are There?
The New Mexico Locust
The New Mexico locust tree, or Robinia neomexicana, is not a Mexican tree as its name suggests. It is predominantly located in the Southwestern part of United States.
This species of locust tree can develop into a shrub or a small tree, growing up to 10 feet tall with striking purple flowering branches in spring and summer.
The Imperial Honey Locust
This honey locust variety, commonly referred to as Impcole, reaches a height of approximately 35 feet.
It produces yellow-green flowers and has feathery leaves reminiscent of ferns. The foliage is green in the spring and summer, turns yellow in the fall, and is shed during winter.
The Shademaster Honey Locust
The Shademaster honey locust tree is noted for its lack of thorns. It also outpaces most locust trees in growth rate. Height of 50 feet and greater are not uncommon.
Shademasters have the benefit of not bearing fruit, which simplifies maintenance in comparison to other locust trees.
The leaves of the Shademaster are green, turning yellow during autumn. The small and fragrant flowers are of a yellow color.
The Skyline Honey Locust
Referred to as Skycole, the skyline honey locust exhibits striking ornamental foliage with pyrimidal frond like leaves. This tree can reach a maximum height of 45 feet and spread to 35 feet.
Similar to Shademasters, skylines are also thornless and fruitless.
The Bristly Locust
Otherwise known as Robinia hispida or ‘moss shrub’, this honey locust grows as a shrub. It can reach a maximum height of 8 feet and bears captivating pink flowers and green leaves.
Bristly locusts have the potential to spread rapidly and become invasive in:
- Pennsylvania
- Michigan
- Ohio
Uses of Honey Locusts
These species of plants are grown for several reasons, which are:
High-Quality Wood
Although honey locusts are not primarily planted for their wood, they do provide reliable timber that is useful in construction and furniture making.
Food and Medicine
Unlike black locusts that have harmful seed pods, honest locusts do bear edible seed pods.
The pulp from the pods of honey locust seeds can be utilized as food or even as traditional Native American medicine. Other uses of the honey locust include:
- Making tea
- Feeding livestock and wildlife, being from the pea family
- Producing beer
It should be noted, however, that a honey locust tree doesn’t play any part in producing actual honey. Its name has more to do with the pleasant taste of its pulp than anything else.
Landscaping
The main reasons they’re cultivated are for landscaping. Though the over-planting of this tree has presented some problems, such as:
- A greater number of pests and tree diseases.
- Barrier creations along rivers which block animals from reaching water streams.
- Invasion of farmlands, preventing crops from growing.
Black Locust Robinia Pseudoacacia Tree
Robinia Pseudoacacia, commonly known as Black locust, are part of the Robinia genus. These trees are strong and fast-growing, residing in the wooded regions alongside the stream banks of the USA.
In addition to its thriving growth, a black locust robinia tree possesses the ability to withstand poor soil conditions, drought, pollution, and even salt. Under abundant sunlight and moderate moisture, these trees can reach up to 70 feet tall and 30 feet wide.
Black locust leaves are blue-green, small, and oval shaped with short sharp thorns. In spring, they are covered with blossoms, and in the fall, they turn yellow and shed.
However, this has variations based on the different types of locusts.
Popular Black Locust Varieties
The Twisty Baby Black Locust Tree
Also known as Lace Lady, this robinia pseudoacacia cultivar can be grown as a shrub or a tree. When planted in the ground, it can reach a height of 20 feet and 5 feet when grown in a pot.
The ‘Twisty Baby’ name comes from the unusual spiraling and contorting way this tree’s branches grow. You can exaggerate the twist on this variety by pruning it back in the cold winter season, making the contortion more pronounced.
The Purple Robe Black Locust Tree
With its captivating visual appeal, this black locust tree variety might be one of the most beautiful trees out there. Its leaves change color during the active growing:
- Blooming: green leaves embellished with soft purple tones.
- Fully formed: bronze distinctly colored leaves
As stunning as the leaves are, the tree is also adorned with densely clustered flowers that stand in stark contrast to the leaves’ pink and purple hues.
The Frisia Black Locust Tree
This exceptional cultivar is slightly smaller than other locusts, reaching a maximum height of 40 feet and a spread of 25 feet. It is, however, a great decorative tree because of its beauty. Its vivid foliage is bright yellow and may at times brighten into lime green shades.
Uses of Black Locust Tree
Due to its strength and durability, black locusts attracted pioneers for other various uses, such as:
Strong Timber
Black locusts are considered as hardwood trees, meaning that they are denser as compared to others.
“Hardwood trees are equipped with xylem vessels, which are used to carry and distribute water through the trees. Their cell walls are lined with lignin, an extremely tough material that is extemely resilient. This stands in stark contrast to softwood, where the vascular structure is not unlike a cluster of drinking straws.” — Maximum Yield
This characteristic makes black locust wood exceptional for construction and making fence posts.
The quick growth of the black locust is another reason it is cultivated a lot.
Long-Lasting Firewood
The dense black locust makes it more difficult to burn than other trees, but in turn makes it more effective as firewood. The firewood burns for longer, making it more efficient when compared to other trees.
Honey Production
The flowers of black locust flowers bloom generously and create broad swaths of blooms which sharply rise in number. Because of this and the copious amounts of nectar, honey bees are drawn toward them.
“These flowers are attractive to bees and provide a good source of nectar. Therefore, black locust trees are planted in regions where honeybees are operating to help them with their honey production.” — Green and Vibrant
Ornamenting and Shading
Due to the heavy blossoming, black locusts are also used as ornamental trees. Their beautifully fragrant flowers are white, pink, or purple in color and measure 4 to 10 inches long.
The branches of black locust are brittle and grow in an erratic manner, full of gaps. This means that the shade provided by such plants is perfect for the needs of other plants.
Problems with Locust Trees
Some regions face cankers, and root collar rot which poses a problem for the more common locust trees.
Cankers develop as splotches that are either flat or discolored on a tree’s trunk and branches. Cankers can spread over time to completely girdle the tree, resulting in death. Cankers also contribute to prolonged stunted growth, and an increase in leaf sparsity or a yellowing.
Root collar rot is another closely related disorder that manifests as yellow or white patches around the base of the tree.
To prevent canker and root collar rot, ensure trees remain vigorous and healthy:
- Make sure to provide water during dry spells, particularly when the tree is not located on an irrigated lawn.
- Avoid injuring the sides of the tree while mowing because the injuries can shield entry points for the diseases.
- Remove infected branches and limbs, ensuring to cut at least 12 inches below the infected area.
- Disinfecting tools between cuts with a 1:10 bleach-water solution ensures pruning saws do not harbor pathogens.
How to Plant and Grow Locust Trees
Plant locust trees in full sun and ensure at least 30 feet of space away from other trees. Water frequently for the first year as roots get established. Older trees seldom require additional watering or fertilization, especially when located in an irrigated, fertilized lawn.
Preparation
Before you plant locust tree seeds, prepare them first by:
- Boil water in a ratio of three to four times the volume of seeds.
- Allow the boiled water to cool for one minute.
- Add the seeds to the hot water container.
- Allow the water to reach room temperature.
- Once the seeds swell to three times their size.
- remove them from the container. Immediately plant the swollen seeds.
Planting and Caring
Locust trees require the following for planting:
- An expansive area where the trees can be cultivated and space to spread.
- Soil enriched with cottonseed meal and gypsum powder.
- Direct sunlight.
- Seasonal timing, ideally spring and summer months.
- Land elevation to drain excess water effectively.
Locust trees require abundant initial watering but cannot be waterlogged. As the trees mature, the need for water diminishes. Regular pruning of dead branches is essential for shape and development regardless of the age of the tree.