Alnus rubra
Alnus rubra, commonly known as Red Alder, is a fast-growing deciduous tree native to the west coast of North America. It is characterised by its smooth grey bark, oval green leaves with serrated edges, and dangling yellow-brown catkins that appear in late winter to early spring. In autumn, the small, woody cone-like fruits provide interest and attract wildlife. Renowned for its ability to fix nitrogen, this hardy tree improves soil quality and thrives in damp or poor soils, making it invaluable for restoration projects.
Well-suited to riparian plantings, wetland gardens, or as a pioneer species in reforestation efforts. It grows best in full sun and tolerates a wide range of soils, from waterlogged to moderately dry once established. Plant in spacious areas to accommodate its rapid growth and spreading habit.
Reaches a mature height of 20–30 m with a canopy spread of 10–15 m, forming a tall, elegant tree with ecological and landscape value.
Trimming: Prune in late winter or early spring to remove dead, damaged, or crossing branches. Regular pruning maintains a strong structure and encourages healthy growth.
Fertilising: Alder trees can thrive in low-nutrient soils due to their nitrogen-fixing abilities. However, a light application of balanced fertiliser in spring can benefit trees in very poor soils.
Watering: Water regularly during the establishment phase. Once established, Alders are highly tolerant of wet conditions and can thrive in waterlogged or damp soils.
Pest Control: Check for aphids on young growth. Use insecticidal soap or introduce natural predators like ladybirds to manage infestations if necessary.
Disease Management: Generally resistant to diseases but may suffer from root rot in compacted or poorly drained soils. Improve drainage and promptly remove any affected trees or branches.
Enjoy complimentary delivery anywhere in mainland New Zealand when you purchase plants worth $250 or more*.
For orders below $250, the following flat-rate delivery charges are applicable:
- Urban delivery within mainland New Zealand: $19.95
- Rural delivery within mainland New Zealand: $39.95
- Waiheke, Chatham and Great Barrier Islands: Please contact us for shipping options.
We aim to have all orders shipped within 14 days from the order date, unless a different shipping date is specified alongside a product.
