Seaside alder is a rare native deciduous tree that blooms in late summer when most plants are winding down, offering showy flowers from August through September. This multi-trunked species grows 20 to 30 feet tall and spreads 16 to 29 feet wide, thriving in zones 4 through 7. Native to three small disjunct populations across the U.S., it's an uncommon tree that handles both wet swamps and surprisingly dry, infertile soils, making it a resilient choice for gardeners working with challenging conditions.
Partial Sun
Moderate
4-7
360in H x 348in W
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Moderate
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Few trees flower in late summer, but seaside alder delivers showy blooms precisely when the garden needs them most. It's equally at home standing in shallow water or enduring drought, tolerates clay soil and erosion without complaint, and carries no known serious pest or disease problems. This deciduous native grows into a graceful, rounded shape and opens doors to habitat restoration and water feature gardening.
Seaside alder serves multiple landscape functions: it works beautifully as a multi-stemmed hedge, thrives in rain gardens where water collects seasonally, and is particularly valuable as a water plant for stream banks, pond margins, and areas prone to flooding. Its late-summer flowering and ability to stabilize soil make it an excellent choice for ecological restoration projects and naturalistic water features.
No timeline data available yet for this variety.
Seaside alder naturally grows as a multi-trunked, upright-rounded shrub or small tree. Allow the plant to develop its natural form with minimal intervention. Light pruning after flowering in fall can maintain shape and size, and any dead or crossing stems can be removed to encourage air circulation. Avoid heavy pruning, which can stress the plant unnecessarily.
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“Seaside alder is a rare native species found naturally in only three small, geographically separated populations across the United States. These isolated populations have each been classified as distinct, making the species uncommon in cultivation but increasingly recognized as important for native plant restoration. Its rarity in the wild and in gardens speaks to the challenges of propagating this particular species, even as conservation efforts and native plant movements have brought renewed attention to its ecological value.”