Page 196 - Tài liệu cây cảnh Bonsai4me Bonsai Basics

frost hardy your Chinese Elm must spend the Autumn outside to harden up for

the Winter; never place a Chinese Elm that has been grown indoors straight
outside during the Winter,
I am reliably informed that given protection from cold winds and mulching
of the pot with straw, soil or bark, Chinese Elm bonsai will actually cope with
temperatures of -10°F. (Zone 6 Winters). Chinese Elms planted in the ground
will survive in zone 5 Winters; that's temperatures down to -20°F (-28°C).
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 elms/acclimatised elms are fully hardy to frost though
freezing winds can result in fine branches dying back if left fully exposed.
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. Elms have very strong and
vigorous rootsystems that need annual rootpruning. Rootbound Elms will grow
poorly.

Trees overwintered indoors can be repotted in Autumn after leafdrop but
before being brought inside. Repot in basic soil mix.
Pruning
One of the main attractions of Elms is the great contrast that can be achieved
between a thick trunk and the delicacy of very fine growth at the tips of the
branches.
Allow shoots to extend 3 or 4 nodes then prune back to 1 or 2 leaves as
required.
Pruning of large branches during the Spring and Summer can cause heavy