Alnus glutinosa
Common alder, European alder, Black alder
- Height × spread
- 20m × 7m
- Position
- Full sun
- Hardiness
- Colder than -20C (RHS H7)
- Flowers
- Winter, Spring
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
The alder is a tree for wet places. As early as January, it has catkins, that give the tree a purple haze before turning yellow. It is a variable tree with regard to shape, sometimes conical, sometimes more rounded or pointed. The leaves are a rounded, fan-shape with toothed edges. When they first emerge they are coloured a soft orange-brown later maturing to dark green. The tree is of practical value in wet areas, as it is happy in flooded land where its roots can bind the soil. It is a commercially useful tree that in the past was used to make many small items, such as eating vessels, spoons, staves for barrels, buckets for carrying liquids and for clogs. It was used in prehistoric times to make piles which support homes built in lakes and marshy areas, as the wood lasts well if immersed in water.
- Flower colour
- Yellow
- Foliage colour
- Green
- Spring foliage
- Red-copper
- Stem colour
- Brown, Grey
- Fruit colour
- Brown
- Variegated
- No
- Scent
- No
- Shape
- Oval
- Height
- 20m
- Spread
- 7m
- Height in 10 years
- 10m
- Spread in 10 years
- 5m
- Season of interest
- Spring, Winter
- Flowers in
- Winter, Spring
- Evergreen
- Deciduous
- Garden style
- Winter garden, Seaside garden
- Sun or shade
- Likes full sun, tolerates part shade
- Soil type
- Clay, Loam (normal), Sandy soil
- Soil pH
- Acid (ericaceous), Neutral
- Drainage
- Moisture retentive soil
- Hardiness
- Colder than -20C (RHS H7)
- Borders & containers
- Borders
- Use for
- Structural, Rabbit resistant, Bee attraction, Bird attraction, Sensory garden (tactile)
- Hazards
- No
Spring
Spring - late · Outdoors
Feed young plants with slow release fertiliser
Spread a slow release fertiliser around the base of the plant to the edge of the foliage spread, so that it can feed the roots. It is helpful for this to be applied for several years.
This is a simple way to provide a nutrient boost until the plant becomes well established.
Spring-Autumn · Outdoors
Water to keep the soil moist
For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.
Without regular watering some plants never fully regain their beauty.
Winter
Winter · Planting
Prune to maintain the plant
Pruning is done in winter when the plant is dormant as otherwise it can 'bleed' badly when cut. Keep the plant looking attractive and healthy by removing dead branches, removing branches that cross or rub each other, and those which spoil its appearance.
The plant is encouraged to develop a pleasing shape by removing deviant or dead growth. It is much more likely to remain healthy if branches that rub, or can rub each other are removed since rubbed spots can be places where disease is introduced.
Planting & general
Outdoors
Water with rain water
This plant needs rain water or soft water (the minerals in alkaline or "hard" water are harmful). This is especially important for plants in pots.
Outdoor planting · Planting
Add root growth stimulant to the planting hole
Mycorrhizal fungi helps roots establish quickly, so they absorb water and nutrients more efficiently. It comes as a powder, granule or gel. Add to the planting hole or container, and to the plant's rootball before planting in the hole. For "bareroot" plants use a gel.
Planting
Protect & support young trees
Attach a newly planted tree or tall shrub over 1m to a tree stake to give support and prevent windrock. Use a tree guard to stop tree bark being eaten by animals, especially in areas with deer - removing bark injures a tree and in worst case can kill it.
Found in
More Alnus
Alnus cordata
Italian alder
Alnus glutinosa 'Imperialis'
Royal alder, Common alder, European alder, Black alder
Alnus glutinosa 'Laciniata'
Common alder, European alder, Black alder
Alnus hirsuta
Manchurian alder
Alnus incana
Grey alder
Alnus incana 'Aurea'
Golden grey alder, Grey alder
Alnus incana 'Laciniata'
Cut leaf grey alder, Grey alder
Alnus incana 'Pendula'
Weeping alder, Grey alder