Chapter 93 Fagus grandifolia
93.1 American beech
An American beech bonsai in the National Arboretum collection. Link to original image
93.2 Soil: Moist Deciduous Mix
Ratio: 4 parts bark, 1 part grit
Add-ins: dolomitic limestone (~5 lbs/yd), Tree-Tone (15 lbs/yd)
pH: ~6.5 (slightly below neutral)
Moisture: best grown in deep, rich, moist but well-drained soils in full sun to part shade. Intolerant of wet, poorly drained soils. Beeches require more water especially if planted in a shallow pot.
93.3 Light
Routine: semi-shade or full sun.
Summer: Mid-day shade and protection from strong winds. Leaf scorching indicates it is getting too much sun.
93.4 Cultivation Notes
93.4.1 Potting & Root Pruning
Schedule: repot in spring as the buds extend, every 2-3 years. Older specimens can be repotted as and when necessary. Beeches are difficult to transplant, which suggests they dislike root pruning.
93.4.1.1 Top & Branch Management
Heavy pruning: Hard pruning can be carried out in late-winter or mid-summer. Removal of large branches can be carried out in midsummer to accelerate wound healing.
Fine pruning: the main growth spurt is in Spring. To improve ramification, pinch out the growth tip after the first or second leaf emerges. This reduces the internodal length.
After spring growth has fully extended, prune back to a bud that is facing the way you wish future growth to head.
Leaf pruning: unknown whether they can tolerate it.
Wiring: needs to be done carefully. The bark marks very easily and wire marks can take an extremely long time to fully disappear from the smooth bark surface. Branches suddenly thicken after spring growth and wire can cut into the bark in a matter of days. Try to make use of guy wires to move branches into shape if at all possible.
93.4.2 Feeding
For trees where trunk or primary branch development is still taking place feed as soon as leaves start to unfurl. For refined trees, withhold fertilizer for 3-4 weeks after leaves appear in spring to keep the vigorous spring growth finer with shorter internodes. After the first flush, feed every 2 weeks until mid-summer.
93.4.3 Pests & Problems
Aphids, bark scale and powdery mildew are occasional problems, but beeches generally are pest-free.
93.4.4 Winter Storage
Frost protection is required when temperatures reach -5°C or less. Store in mulch outdoors. Try to place in a shaded area so buds do not break in a mid-winter warm spell.
93.5 Propagation Notes
Sow seed outside in autumn or after winter stratification in spring. In my experience, many native beech nuts are empty, infertile husks. If you are planting collected nuts, expect less than 10% to germinate.
93.6 Artistic & Styling Notes
Beeches are slow-growing so creating a large-trunked bonsai is a slow process. For this reason, beeches are commonly seen in group plantings where trees with relatively thin trunks can be used.
93.7 Additional Information
93.7.1 Natural History
American beech is native throughout eastern North America. If grown as solitary specimen trees, they mature into tall stately trees with a spherical crown with dense branches that reach nearly to the ground.
Trunks have distinctive thin, smooth, gray bark that is easily damaged and will not heal easily.
In the wild, beeches often form thickets or colonies by suckering from the shallow roots.
Beech requires long, warm summers to thrive, so do well in our area.
93.7.2 In Cultivation
It is difficult to find American beeches in nurseries. European and Japanese beeches are more common, but also are not as hardy here.