Bonsai Training Information

Alnus glutinosa
Common Alder, Black Alder

The Common Alder is native throughout the British Isles and much of Continental Europe. It can be found on on wetter soils and often to high elevations and even on infertile terrains. The Alders have catkins with male and female ones on the same tree. The male catkin is loaded with about 120 individual flowers and 480 pollen-producing stamens, which after shedding their clouds of yellow pollen wither and fall.


Formal upright, Informal Upright, Slanting, Cascade, Semi-cascade, Literate, Broom, Rock-over-root, Clasped-to-rock, Twin-trunk, Clump, Group planting, Saikei




Full Sun or Partial Shade. In summer protect from drying out and position in dappled shade area if required.


It like a wet soil, keep soils moist at all times. Water well duing summer, ensuring soil doe snot dry out, in winter keep soil moist but not water logged.


Use a Balanced Fetiliser during growing season, feeding every 3-4 weeks.

Leaf and Branch Pruning:

During the growing season reduce to 2 leafs on stem once it has reached 4 or 5 leafs on stem. Carry out heavy branch and structural pruning in Autumn when plant is dormant. Cut away any die back to healthy tissue.

Re-potting & Growing Medium:

Every 2 years at the begining of spring or in autumn once plant goes dormant. Upto 30% of root ball may be pruned back. While the will tolerate a wide range of soils they like water retentive soils, use a heavy clay soil Loam 1 part Clay, 1 part Loam, 1 part Sharp Sand 30% ( 1 Part Akadama and 1 Part Leaf Mould or Bark)


In spring but protect delicate bark. It is quite flexible even with even thick branches bending quite easily. Best to use some protective raffia on thicker branches. Leave on for between 4-6 months, checking regularly for scarring.


The Alnus do not like their roots being frozen so best to move into cool green house during the coldest of winter months.

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