Species seaside alder
green fruits with green leaves on light-green stems and brown branches

seaside alder

Alnus maritima

The Seaside Alder (Alnus Maritima) is an amazing plant species that shines on both land and water. It’s a deciduous tree that thrives in poor, sandy soils near the ocean—making it an ideal choice for coastal home gardens. With its gnarled, rounded branches, the Seaside Alder provides shady shelters for wildlife and food sources for birds. It’s a rapidly-growing species that features catkin flowers and cone-like fruits, providing abundant biodiversity and adding to the beauty of the environment. Enjoy the Seaside Alder’s many benefits and watch your space transform!

Cycle:

Perennial

Watering:

Average

Propagation:

Cutting,Layering Propagation,Grafting Propagation,Seed Propagation,Division

Hardiness Zone:

4 - 7

Flowers:

Yellow Flowers

Sun:

full sun,part shade

Cones:

Yes

Leaf:

Yes

Growth Rate:

Low

Maintenance:

Moderate

Drought Tolerant:

Yes

Salt Tolerant:

Yes

Care Level:

Medium

watering

The seaside alder requires regular watering throughout its growing season—from spring to late summer. During the summer, water the seaside alder deeply twice a week and check the soil to ensure that it is continuously moist. Do not allow it to dry out completely, as this will cause damage to the plant. During milder weather, water only once a week. In periods of extreme heat, increase the frequency of watering to 3 times a week. In the winter, water only when there is no rain for a prolonged period of time.

sunlight

Seaside alder (Alnus maritima) requires a minimum of 6 hours of direct sunlight per day to thrive, though the healthiest plants will receive at least 8 hours. If the plant is unable to receive an adequate amount of sunlight, supplemental lighting can be provided to mimic natural sunlight. It is best to avoid direct afternoon sunlight, as this has a tendency to be too harsh and can lead to leaf scorch. Morning and late afternoon sunlight are ideal, as the sun is not as intense during these times of day. Additionally, seaside alder should not be planted anywhere that receives intense, reflected sunlight as this can undermine its growth potential.

pruning

Seaside Alder (Alnus maritima) is best pruned in late winter or early spring while the plant is still dormant. Pruning in late winter to early spring will help maintain the desired mature size and shape of the plant. Minor pruning can be done at any time of the year to keep the plant looking tidy. Avoid pruning before or during bud break as this may remove the potential for new growth and blooms. Generally, it is best to remove only about 1/3 of the plant’s growth each year to maintain shape and health. Severe pruning should be avoided as it will weaken the plant.

Season

Fall
Winter
Spring
Summer
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Starts Flowering

Seaside alder typically starts flowering in April.

Hardiness Map