Alnus maritima
Common Name(s):
Previously known as:
- Alnus metoporina
- Phonetic Spelling
- ALL-nus mah-RI-tee-mah
- Description
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Seaside alder is a deciduous small tree or large shrub in the birch family (Betulaceae). Native only to three small disjunctive populations, with each classified as a separate subspecies (subspecies maritima in the coastal plains of Southern Delaware and the eastern shore of Maryland, subspecies georgiensis in northwest Georgia, and subspecies oklahomensis in south-central Oklahoma). In nature, it is often found growing beside streams and ponds near coastal areas and sometimes in standing water, making it well-suited to wet soils or areas with seasonal flooding. The genus name is Latin for alder and the species name comes from the Latin "growing by the sea".
Growing at a medium rate it reaches a mature height of 20 to 30 feet tall and 16 to 30 feet wide, Thriving in part shade as well as sun, seaside alder tolerates clay and alkaline soils, and is somewhat drought tolerant once established. It also tolerates saline soils, but will not do well in full shade.
Its dense deciduous foliage is attractive to nesting birds and makes it suitable as a windscreen, hedges, or specimen plant. It is also known for its ability to fix nitrogen in the soil. Other landscape uses include rain gardens, riparian, and naturalized areas, especially those with wet soils.
Insects, Diseases, and Other Plant Problems: No serious problems.
VIDEO created by Grant L. Thompson for “Trees, Shrubs, and Woody Vines for Landscaping” a plant identification course offered by the Department of Horticulture at Iowa State University.
- Profile Video:
- See this plant in the following landscape:
- Cultivars / Varieties:
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- Alnus maritima subsp. oklahomensis 'September Sun'
oklahomensis is noted for green foliage and vigor; 'September Sun' grows rapidly with dense foliage.
- Alnus maritima subsp. oklahomensis 'September Sun'
- Alnus maritima subsp. oklahomensis 'September Sun'
- Tags:
- Cultivars / Varieties:
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- Alnus maritima subsp. oklahomensis 'September Sun'
oklahomensis is noted for green foliage and vigor; 'September Sun' grows rapidly with dense foliage.
- Alnus maritima subsp. oklahomensis 'September Sun'
- Alnus maritima subsp. oklahomensis 'September Sun'
- Tags:
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Attributes:
- Genus:
- Alnus
- Species:
- maritima
- Family:
- Betulaceae
- Life Cycle:
- Woody
- Country Or Region Of Origin:
- United States
- Distribution:
- DE, GA, MD, OK
- Wildlife Value:
- Nesting site for birds.
- Dimensions:
- Height: 20 ft. 0 in. - 30 ft. 0 in.
- Width: 16 ft. 0 in. - 29 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Shrub
- Tree
- Woody Plant Leaf Characteristics:
- Deciduous
- Habit/Form:
- Multi-stemmed
- Multi-trunked
- Pyramidal
- Rounded
- Growth Rate:
- Medium
- Maintenance:
- 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
- Loam (Silt)
- Soil pH:
- Acid (<6.0)
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Frequent Standing Water
- Moist
- Occasional Flooding
- Occasionally Wet
- Available Space To Plant:
- 12-24 feet
- 24-60 feet
- USDA Plant Hardiness Zone:
- 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b
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Fruit:
- Fruit Color:
- Brown/Copper
- Green
- Display/Harvest Time:
- Spring
- Summer
- Fruit Length:
- 1-3 inches
- Fruit Width:
- 1-3 inches
- Fruit Description:
- Small upright cones in spring and summer.
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Flowers:
- Flower Color:
- Gold/Yellow
- Green
- Purple/Lavender
- Red/Burgundy
- Flower Inflorescence:
- Catkin
- Insignificant
- Flower Bloom Time:
- Fall
- Summer
- Flower Size:
- 1-3 inches
- Flower Description:
- Produces insignicant blooms from late summer to early fall.
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Leaves:
- Woody Plant Leaf Characteristics:
- Deciduous
- Leaf Color:
- Green
- Leaf Feel:
- Glossy
- Leathery
- Deciduous Leaf Fall Color:
- Insignificant
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Leaf Shape:
- Elliptical
- Oblong
- Obovate
- Ovate
- Leaf Margin:
- Serrate
- Hairs Present:
- No
- Leaf Length:
- 1-3 inches
- Leaf Width:
- 1-3 inches
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Bark:
- Bark Color:
- Light Gray
- Surface/Attachment:
- Smooth
- Bark Description:
- Light gray, smooth bark.
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Stem:
- Stem Color:
- Brown/Copper
- Red/Burgundy
- Stem Is Aromatic:
- No
- Stem Bud Scales:
- Enclosed in 2 scales
- Stem Lenticels:
- Not Conspicuous
- Stem Surface:
- Smooth (glabrous)
- Stem Description:
- Hairy (pubescent) when young, Smooth (glabrous)
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Landscape:
- Landscape Location:
- Naturalized Area
- Riparian
- Woodland
- Landscape Theme:
- Rain Garden
- Water Garden
- Design Feature:
- Hedge
- Small Tree
- Specimen
- Attracts:
- Songbirds
- Resistance To Challenges:
- Drought
- Erosion
- Poor Soil
- Wet Soil
- Wind