Page 198 - Tài liệu cây cảnh Bonsai4me Bonsai Basics

evergreen where as outdoor cultivation results in a deciduous tree. Ensure indoor

trees do not become too cold in their first winter outside. Zelkovas should be
able to cope with the adverse growing conditions indoors though they are never
as vigorous as their outdoor counterparts.
Position
(Indoors) Well lit, cool position on a sunny windowsill during the winter.
Keep up humidity levels. Place outside from May onwards after last frosts have
finished. Try to keep outside until Autumn when the leaves can be allowed to
fall naturally before bringing indoors.
(outdoors) Outdoor Zelkovas/acclimatised Zelkovas are hardy to frost though
temperatures below -5°C can result in fine branches dying back and root damage
so should be afforded some protection. Frost protection can include placement in
darkened outhouses and garages as when out of leaf Zelkovas do not require
light.
Watering
(indoors) Never allow compost to dry out, keep the compost evenly moist.
Check the compost daily but only water when necessary. Watering daily as a

routine results in sodden compost, leading to lack of vigour, rootrot and
eventually death.
(outdoors) As with indoor watering though during periods of strong sun, high
temperatures or strong growth in the Spring, trees can need far more frequent
watering.
Feeding
(indoors) Balanced feed weekly through Spring and Summer. Monthly
through the winter. Do not feed when out of leaf.
(outdoors) Once buds open in Spring, feed weekly with high nitrogen for
first month then every two weeks until late summer with balanced feed.
Repotting In Spring as buds extend annually until around 10years old or
more and then repot as required. Trees overwintered indoors can be repotted in
Autumn when brought indoors after leafdrop. Repot in basic soil mix.

Pruning Allow shoots to extend 3 or 4 nodes then prune back to 1 or 2 leaves
as required Larger-leaved Zelkovas respond well to leaf cutting in Summer
Wiring In midsummer though indoor trees can be wired mid-winter
particularly if out of leaf. Care should be taken as bark marks easily.
Propagation Sow seed outdoors in Autumn or Spring. Greenwood cuttings
in Summer. Hardwood cuttings in Winter. Airlayering after spring growth has
hardened.
Pests and diseases Zelkova bonsai as with all Elm bonsai are not affected by
Dutch Elm Disease as the beetle requires the volume of wood only available to it