Betulaceae
Common Alder (Alnus glutinosa)
Alnus glutinosa
Common alder is a low-maintenance, hardy tree once established. It thrives in full sun to partial shade and tolerates consistently wet or even waterlogged soil, though it also withstands short dry spells. Its nitrogen-fixing roots mean it rarely needs fertilizing, and pruning should be minimal since heavy cuts can stress the tree. Watch for Phytophthora root rot in waterlogged sites and occasional aphids or leaf miners.
Every 7 days
Bright indirect
-30° - 35°C
% - %
Categories
What is Common Alder?
Common Alder (Alnus glutinosa) is a easy-care plant from the Betulaceae family. The common alder (Alnus glutinosa) is a fast-growing deciduous tree native to Europe, western Asia, and North Africa, prized for its ability to thrive in wet, boggy, and riverside soils where few other trees survive. Reaching up to 25 meters, it produces distinctive reddish-brown catkins in late win...
Common Alder grows up to 25.0m, spread of 800cm, watering every 7 days, -30°C – 35°C. It is not suitable for indoor environments and safe for pets.
Unlike many tropical plants, Common Alder tolerates watering mistakes. Best for beginners. Unlike many popular species, Common Alder is safe to keep around pets.
How to Care for Common Alder?
TLDR: Common Alder needs Bright indirect, watering every 7 days, and temperatures between -30-35°C with 40-70% humidity.
How Often Should You Water Common Alder?
Keep soil consistently moist to wet, especially for young trees; established alders growing near water rarely need supplemental watering.
How Much Light Does Common Alder Need?
Plant in full sun to partial shade in an open site; alder will not thrive in deep shade.
What Is the Best Soil for Common Alder?
Adapts to clay, loamy, sandy, or peaty soils from acidic to slightly alkaline (pH 5.0-7.5); tolerates poor drainage and periodic flooding better than almost any other tree.
What Pot Should You Use for Common Alder?
Not suited to container growing long-term; plant directly in the ground in a moist or wet site with room to reach full size.
What Is Common Alder and Where Does It Come From?
The common alder (Alnus glutinosa) is a fast-growing deciduous tree native to Europe, western Asia, and North Africa, prized for its ability to thrive in wet, boggy, and riverside soils where few other trees survive. Reaching up to 25 meters, it produces distinctive reddish-brown catkins in late winter before its rounded, glossy leaves emerge, followed by small woody cone-like fruits that persist into winter. Its roots host nitrogen-fixing bacteria (Frankia alni), allowing it to enrich poor soils naturally, making it a valuable pioneer species for riverbank stabilization, wetland restoration, and windbreaks.
How to Propagate Common Alder?
Seed sowing
Fresh seed germinates best; alder seed loses viability quickly in dry storage.
- 1 Collect ripe cones in autumn and extract seeds once dry
- 2 Cold-stratify seeds in moist sand in the refrigerator for 6-8 weeks
- 3 Sow in trays of moist, lightly covered soil in late winter
- 4 Keep consistently moist until germination in spring
- 5 Transplant seedlings once they have several true leaves
Materials needed:
Hardwood cutting
Rooting hormone can improve success rates but is not essential for this species.
- 1 Take hardwood cuttings 20-30 cm long from dormant one-year-old wood in late winter
- 2 Insert two-thirds of the cutting into moist, well-draining soil or a rooting bed outdoors
- 3 Keep soil consistently moist through spring
- 4 Roots and shoots should appear by late spring
Materials needed:
How Big Does Common Alder Grow?
TLDR: Common Alder can reach up to 25.0m tall with Fast growth rate.
Max height
25.0m
Spread
8.0m
Growth rate
Fast
Foliage
Deciduous
Plant Uses
Ornamental
Great for decoration
Medicinal
Medicinal properties
Medicinal Uses
- Bark and leaves traditionally used as an astringent for skin inflammation, sore throats, and minor wounds
Is your plant showing symptoms?
Click on the symptom to discover possible causes:
What Diseases Commonly Affect Common Alder?
TLDR: Common Alder is susceptible to 7 known diseases. Monitor regularly for early detection.
Phytophthora Root Rot
Disease caused by fungus-like organisms (oomycetes) that live in soil and can survive for years. It affects roots, stem, and crown of plants, being especially severe in waterlogged or poorly drained soils. It is the second most common cause of root rot in trees and shrubs.
Canker
Canker is a disease caused by various fungi and bacteria that create necrotic, sunken areas on bark of branches, stems, and trunks. Pathogens enter through wounds and natural openings, especially when plants are stressed. Canker can gradually weaken or kill branches by disrupting water and nutrient flow.
Powdery Mildew
Powdery mildew is a common fungal disease caused by various fungi species including Erysiphe, Podosphaera, Oïdium, and Leveillula. It affects over 10,000 plant species worldwide. The disease thrives in warm, dry climates with high humidity and appears as a distinctive white powdery coating on plant surfaces.
Aphids
Aphids are small, soft-bodied, pear-shaped insects (1/16 to 1/8 inch long) that feed by sucking nutrient-rich sap from plants. They reproduce rapidly and can quickly weaken plants, causing distorted growth and transmitting plant viruses. Aphids come in various colors including green, black, red, yellow, brown, and gray. They secrete honeydew, a sticky substance that attracts ants and encourages sooty mold growth.
Meaning & Symbolism
In Celtic and European folklore, the alder symbolizes resilience and protection - a tree that thrives at the meeting point of fire (its wood makes prized charcoal) and water (its roots stabilize riverbanks).
Fun Facts
Alder roots host colonies of Frankia bacteria that convert nitrogen from the air into a form the tree can use, fertilizing the soil around it.
Alder wood resists rot when kept permanently underwater, which is why much of historic Venice was built on alder piles.
Male catkins form in autumn and hang visibly on bare branches all winter before opening and releasing pollen in early spring.
Frequently asked questions
Can common alder grow in waterlogged soil?
Does common alder need fertilizer?
Is common alder toxic to pets or humans?
What is the biggest disease threat to common alder?
How fast does common alder grow?
Compare with similar plants
| Attribute | Difficulty | Light | Watering | Pet Safe |
|---|---|---|---|---|
| Field Maple | Easy | Bright indirect | 14d | ✓ |
| Silver Birch | Easy | Direct sun | 14d | ✓ |
| Common Blanketflower | Easy | Direct sun | 10d | ✓ |
| Cushion Bush | Easy | Direct sun | 14d | ✓ |
Choose & Compare
Sources & References
- Common Alder (Alnus glutinosa) Growing & Care Guide for Gardeners
- Common Alder - Alnus glutinosa | NC State Extension Gardener Plant Toolbox
- Black alder (Alnus glutinosa) Care Guide - ForwardPlant
- Alnus glutinosa (European alder) | CABI Compendium
- Alnus glutinosa Threatened by Alder Phytophthora: A Histological Study of Roots
