Bristly Locust Rose-Acacia

Basic Information

Tree ID:

Family:

Genus and species:

Description:

Rose acacia, Bristly locust . This flowering shrub grows up to approximately 6 meters tall, featuring dark green, compound pinnate leaves on bristly stems, with clusters of fragrant, pea-like, rose-pink flowers that attract bees and butterlies in the late spring and early summer. The Rose acacia can tolerate poor, dry soils, and its flowers bloom either during late spring or early summer, and it's growth rate is relatively fast and moderate. Bristly locust is perhaps the best erosion control shrub for steep sloping sites with active erosion. It provides quick, woody, vegetative cover on droughty, critical areas needing stabilizing cover. In comparison with most other shrubs it will excel in seedling vigor. It has the ability to fix nitrogen in the soil, and with light shade it does not inhibit growth of annual and perennial herbs. SOURCE: https://plants.usda.gov/factsheet/pdf/fs_rohif8.pdf

Surveyors:

Sneha Mittal, Sarah Lee

Location

Area:

Marsh and Farnam Gardens

Collected Data

Tree shape:

Shrubby, Tabular to Spreading

Date of tree entry:

02/07/2018

Height:

6.00 m

Diameter at breast height:

0.18 m

The tree is not tall enough to measure DBH, so this is a measure of the base of the tree

There is some other reason the DBH cannot be measured accurately

Bark

BARK: The bark of the trunk and larger branches is gray and fairly smooth. Young branches are zigzag, green with very bristly-hairs. These long bristly hairs are purple-brown and sticky. SOURCE: http://www.mortonarb.org/trees-plants/tree-plant-descriptions/bristly-locust

Twigs & branches

TWIGS & BRANCHES: The Bristly locust is an open branched, straggly, and woody legume of vigorous growth. The plant has spines, prickles or thorns, and in the winter, it's twig color is either brown, gray or red. SOURCE: https://gobotany.newenglandwild.org/species/robinia/hispida/

Foilage

FOLIAGE: Deciduous (seasonally loses leaves); Alternate, pinnately compound with elliptical 7 to 15 leaflets. The green stalk (rachis) is sticky, hairy, and has a pair of sharp spines at the base. Upper leaves are green while their lower surfaces are pale green. Each leaf's blade length is approximately 150-300 mm long, and there is one leaf blade per node along the stem. Moreover, the edge of the leaf blade has no teeth or lobes. SOURCE: http://www.mortonarb.org/trees-plants/tree-plant-descriptions/bristly-locust; https://gobotany.newenglandwild.org/species/robinia/hispida/ PHOTOS: http://www.finegardening.com/plant/rose-acacia-bristly-locust-robinia-hispida; https://extension.umass.edu/landscape/weeds/robinia-hispida

Reproductive Structures

Attractive, rose-colored, pea-like flowers in hanging clusters are located in leaf axis and at the end of branches. These fragrant flowers of the Bristly Locust are pink or pink-purple and pendulous. They attract bees and butterflies, which pollinate the flowers. Sometimes, bristly seed pods come after the flowers. Bloom period is late spring to mid-summer. Source: “Rose acacia, Bristly locust.” Fine Gardening. Retrieved on 24 April 2018 from http://www.finegardening.com/plant/rose-acacia-bristly-locust-robinia-hispida. PHOTOS: https://sheffields.com/seeds/Robinia/hispida; https://permies.com/t/35866/Rose-Acacia-Bristly-Locust-ID

Fruit

FRUIT: Fertile flowers are replaced by flat pod, 2 to 3 inches long and very bristly. Not very prolific. Seeds are about 3/16 inch in size, dark brown, and very hard. SOURCE: http://www.mortonarb.org/trees-plants/tree-plant-descriptions/bristly-locust; https://plants.usda.gov/factsheet/pdf/fs_rohif8.pdf PHOTOS: https://fineartamerica.com/featured/rose-acacia-bristly-locust-seed-pods-constantine-gregory.html; https://gobotany.newenglandwild.org/species/robinia/hispida/

Seasons

Early Spring_no flowers or fruits yet
Early Spring_Rose acacia, Bristly locust
Early Spring_no flowers or fruits yet, just thorns
Late Winter_snow on the ground, thorny
Late Winter_Rose acacia, Bristly locust
Late Winter_Rose acacia, Bristly locust

Research

Natural range of distribution:

Habitat:

The Bristly Locust thrives in habitats that include thin upland woodlands, woodland edges, fence rows, thickets, banks of drainage canals, roadside embankments, overgrown waste areas, and vacant lots. While they are indigenous to the southeastern United States, the hilly regions in particular, bristly locusts have adapted to northern areas (as shown in the Distributional Map above).

Origin, history, and uses:

Bristly locust originated in the southeastern United States (“Robinia hispida”) but has since spread to the northeast. The plant has proven to be quite useful for erosion control, as it can provide vegetative cover on areas susceptible to erosion. These areas include surface mine spoil reclamation, industrial waste piles, road banks, cuts and fills. The plant can also fix nitrogen in the soil and can tolerate acidic soils. The shrub is also attractive (“Plant Fact Sheet – Bristly Locust”).

Phenology:

The bristly locust follows an angiosperm life cycle. It begins to bloom in early summer and continues irregularly during the weeks that follow (“ROBINIA hispida”).

References:

Distributional Map:

“Bristly Locust Robinia hispidia L.” Early Detection & Distribution Mapping System. Retrieved on 23 April 2018 from https://www.eddmaps.org/distribution/uscounty.cfm?sub=11577.

Habitat:

Hilty, John. “Bristly Locust.” Illinois Wildflowers. Retrieved on 23 April 2018 from http://www.illinoiswildflowers.info/trees/plants/bristly_locust.htm.

Origin, history, uses:

“Plant Fact Sheet – Bristly Locust.” Natural Resources Conservation Service, United States Department of Agriculture. Retrieved on 23 April 2018 from https://plants.usda.gov/factsheet/pdf/fs_rohif8.pdf.

“Robinia hispida.” Arboquebecium. Retrieved on 23 April 2018 from http://www.arboquebecium.com/en/product/bristly-locust/.

Phenology:

“ROBINIA hispida.” Learn2Grow. Retrieved on 24 April 2018 from http://www.learn2grow.com/plants/robinia-hispida/.