Betula pubescens
The Downy Birch is native to much of the Northern Temperate area from the British Isles, through Europe across Russian and on onto Northern China. It is very similar to the Silver Birch, often growing in the same habitats and as young trees, they look remarkably alike, but unlike the Silver Birch, the Betula pubescens is downy on its leaves and young stems.
Styles and Sizes: As bonsai, they make medium to large bonsai in most upright styles. Position: As a pioneer species the Downy birch loves a full sun position, but it does not like its pot to hot so best place in a shaded position over the hottest parts of the year.
Watering: As with other birches it loves a moist soil but does not like it root wet all the time so ensure the bonsai is watered in the morning, so most of the water is used before the night.
Feeding: Feed with a balanced organic feed, every two weeks if using a liquid feed, every other month if using a pelletised version or after the pellets have fully dissolved away. Begin feeding when the leaves have entirely greened up usually from mid-spring onwards. If the summer is regularly hot, above 30°C, then hold off feeding.
Repotting: Young birches grow roots rapidly and need to be repotted every year. Older trees can be re-potted as necessary, generally, if the growth in the current year is not as healthy as it can be it will benefit from a repotting in the following spring. Use a well-mulched bark, sharp sand, in equal parts. Alternatively, you can use a mix of Akadama, Pumice in equal parts.
Pruning: Trim back shoots to leave 3 lateral shoots or active leaf buds. Structural pruning on more massive branches is best carried out late in the year at the end of autumn or early winter as birches “bleed” profusely.
Wiring: Wire in autumn and remove carefully in spring.