Robinia x ambigua 'Idahoensis'
Common Name(s):
- Phonetic Spelling
- roh-BIN-ee-uh am-big-yoo-uh
- This plant has low severity poison characteristics.
- See below
- Description
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Idaho Locust is a fast growing, upright, flowering tree in the pea family that can reach a mature height of 30 to 40 feet and an equal width. It has a vase-like habit and the foliage is light green in spring, gradually turning blueish in summer, and yellow in fall. Fragrant, bright red blossoms appear in spring time. The genus name honors Jean Robin, botanist to Louis XIII of France, and Vespasian Robin his son. The species name is Latin meaning ‘ambiguous', referring to its parentage.
Idaho Locust prefers moist, well-drained soil. Propagate by hardwood cuttings or sow seeds in the fall. Once established, it is drought tolerant.
This is a small to medium sized, low maintenance tree that tolerates compacted or poor soils and is useful as a street tree.
Idaho Locust is believed to be a cross between Robinia pseudoacacia and Robinia hispida. Its upright habit is similar to Robinia pseudoacacia and the red flowers are similar to those of Robinia hispida.
Insects, Diseases, and Other Plant Problems:
Susceptible to aphids. Fusarium, armillaria, and root rot can also be problems.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- Tags:
- Cultivars / Varieties:
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- Tags:
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Attributes:
- Genus:
- Robinia
- Family:
- Fabaceae
- Life Cycle:
- Woody
- Recommended Propagation Strategy:
- Seed
- Stem Cutting
- Wildlife Value:
- Attractive to bees, butterflies and birds.
- Play Value:
- Fragrance
- Dimensions:
- Height: 20 ft. 0 in. - 30 ft. 0 in.
- Width: 20 ft. 0 in. - 30 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Tree
- Woody Plant Leaf Characteristics:
- Deciduous
- Habit/Form:
- Columnar
- Erect
- Open
- Oval
- Vase
- Growth Rate:
- Rapid
- Maintenance:
- Low
- Texture:
- Medium
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- Clay
- Sand
- Shallow Rocky
- Soil pH:
- Acid (<6.0)
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Moist
- Occasionally Dry
- Available Space To Plant:
- 12-24 feet
- 24-60 feet
- NC Region:
- Coastal
- Mountains
- Piedmont
- USDA Plant Hardiness Zone:
- 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
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Fruit:
- Fruit Color:
- Brown/Copper
- Display/Harvest Time:
- Fall
- Fruit Type:
- Legume
- Fruit Description:
- Seed is in the shape of a pod
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Flowers:
- Flower Color:
- Pink
- Purple/Lavender
- Flower Inflorescence:
- Raceme
- Flower Value To Gardener:
- Fragrant
- Showy
- Flower Bloom Time:
- Spring
- Summer
- Flower Size:
- 1-3 inches
- Flower Description:
- Fragrant, pea-like, purple/ pink 2 inch flowers appear in clusters on pendant racemes. Both female and male parts are in the same flower (that is, perfect).
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Leaves:
- Woody Plant Leaf Characteristics:
- Deciduous
- Leaf Color:
- Blue
- Green
- Leaf Value To Gardener:
- Showy
- Deciduous Leaf Fall Color:
- Gold/Yellow
- Leaf Type:
- Compound (Pinnately , Bipinnately, Palmately)
- Hairs Present:
- No
- Leaf Length:
- < 1 inch
- Leaf Width:
- < 1 inch
- Leaf Description:
- Green leaves become blue green during the summer and yellow in the fall. Individual leaflets are 3/4 of an inch long and 1/2 an inch broad.
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Bark:
- Bark Color:
- Dark Brown
- Light Brown
- Surface/Attachment:
- Furrowed
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Stem:
- Stem Is Aromatic:
- No
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Landscape:
- Landscape Location:
- Recreational Play Area
- Walkways
- Landscape Theme:
- Butterfly Garden
- Children's Garden
- Drought Tolerant Garden
- Pollinator Garden
- Design Feature:
- Flowering Tree
- Screen/Privacy
- Street Tree
- Attracts:
- Bees
- Butterflies
- Songbirds
- Resistance To Challenges:
- Drought
- Problems:
- Messy
- Problem for Cats
- Problem for Dogs
- Problem for Horses
