Alnus cordata
| Alnus cordata | |
| Light: |   |
| Moisture: |    |
| Hardiness: | 6 |
| Soil pH: | 5.6-8.4 |
| Height: | 82' |
| Width: | 26' |
| Speed: | Fast |
| Blooms: | Early Spring |
| Open Woods Forest | |
| Native to: | |
| Nitrogen Fixer | |
| Tea: | Yes |
 | |
Alnus cordata (common name: italian alder)
Propagation: Seed - best sown in a cold frame as soon as it is ripe and only just covered[1]. Spring sown seed should also germinate successfully so long as it is not covered[1][K]. The seed should germinate in the spring as the weather warms up. When large enough to handle, prick the seedlings out into individual pots. If growth is sufficient, it is possible to plant them out into their permanent positions in the summer, otherwise keep them in pots outdoors and plant them out in the spring.
If you have sufficient quantity of seed, it can be sown thinly in an outdoor seed bed in the spring[2]. The seedlings can either be planted out into their permanent positions in the autumn/winter, or they can be allowed to grow on in the seed bed for a further season before planting them.
Cuttings of mature wood, taken as soon as the leaves fall in autumn, outdoors in sandy soil.
Cultivation: Thrives on poor and dryish soils, even on chalk, but prefers to be near water[3][1]. Prefers a heavy soil and a damp situation[4][3]. Grows well in heavy clay soils. Tolerates very infertile sites[3][1].
This species has a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[1].
A very ornamental tree[4], it is very fast growing, reaching 12 metres tall in 20 years in an exposed maritime position at Rosewarne in N. Cornwall[5]. Very tolerant of salt winds, it establishes rapidly in exposed positions[5].
According to World Economic Plants, the correct author of this species is (Loisel.)Loisel. and not Desf. as we have given here. However, since all our other sources have quoted Desf., we have decided not to alter it at this time (1999)[K].
Range: Europe - S. Italy, Corsica.
Habitat: Very rarely self-sown in Britain, but not naturalised.
Usage: An excellent windbreak for maritime areas[5], it grows quite quickly and establishes well even in very windy sites[K]. Trees 5 years old from seed have reached 4 metres in height and are showing no signs of wind-shaping in a very exposed site in Cornwall[K].
This is an excellent pioneer species for re-establishing woodlands on disused farmland, difficult sites etc. Its fast rate of growth means that it quickly provides sheltered conditions to allow more permanent woodland trees to become established. In addition, bacteria on the roots fix atmospheric nitrogen - whilst this enables the tree to grow well in quite poor soils it also makes some of this nitrogen available to other plants growing nearby. Alder trees also have a heavy leaf canopy and when the leaves fall in the autumn they help to build up the humus content of the soil. Alder seedlings do not compete well in shady woodland conditions and so this species gradually dies out as the other trees become established[K].
Pollinators: Wind
Soil: Can grow in medium and heavy soils.
Wind: Tolerates maritime wind exposure
In Leaf: Mid Spring-Early Winter
Flower Type: Monoecious
Heavy Clay: Grows in heavy-clay soils.
Also Known As: A. cordifolia.
Links
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
- ↑ Sheat, Wilfrid. Propagation of Trees, Shrubs and Conifers. St Martin, 1948.
- ↑ 3.0 3.1 3.2 Bean, William. Trees and Shrubs Hardy in Great Britain. Murray, 1981.
- ↑ 4.0 4.1 Chittendon, Fred. RHS Dictionary of Plants. Oxford University Press, 1951.
- ↑ 5.0 5.1 5.2 Rosewarne Experimental Horticultural Station. Shelter Trees and Hedges. Ministry of Agriculture, Fisheries and Food, 1984.