Lovely Chinese Elm exposed root style. These trees are from a big batch just landed in at Premier Bonsai. Please note you will not receive the exact tree pictured but one just like it. It will be planted into a blue pot. The pictures are for illustration only.
Chinese Elm bonsai trees are one of the most popular species used for bonsai, especially for beginners. Fine twiggy branching can be built up very quickly. They are a very forgiving species. Although with the right skills these trees can be grown indoors we recommend growing these trees outdoors all year around. The result will be a much more hardy tree with lots more vigour. Feed & water well during the growing season. Prune back shoots regularly to 1 to 2 leaves after shoots have extended 5 or so leaves.
Genus overview
Genus
of about 45 species of deciduous, semi-evergreen trees occurring
in woodland, thickets and hedgerows in Northern temperate
regions. Ulmus have alternate, ovate to elliptic toothed leaves
usually with very unequally sized bases. Most species display
good fall colour.
Chinese
Elm Bonsai/Harry Harrington
Ulmus species
and in particular Ulmus parvifolia/Chinese Elm are often confused
with Zelkova species, in particular Zelkova serrata/Japanese
Elm. Zelkova are classed as a seperate genus to Ulmus as they
have fruits that are unwinged as opposed to the winged friuts
of Ulmus. Zelkova also differ in that they have single-toothed
leaves whereas Ulmus have double-toothed leaves.
(Zelkova are
listed under their own species guide).
The most common
Ulmus species used for bonsai is the Chinese Elm /Ulmus parvifolia,
however there is no reason why any of the many Ulmus species
cannot be used.
Ulmus minor leaf 
Ulmus parvifolia leaves
English Elm
Notes for
bonsai cultivation
Ulmus parvifolia/Chinese
Elm are often sold as indoor bonsai and as such are acclimatised
to indoor growing conditions, however Chinese Elms are temperate
trees and fully frost hardy. Chinese Elms grown indoors (or
in climates with very mild winters) will remain evergreen
whereas outdoor cultivation results in a deciduous tree.
Though Elms should
be able to cope with the adverse growing conditions indoors,
they are never as vigorous as their outdoor counterparts.
To be entirely 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 calluses;
if necessary, the size of the scar can be reduced by carrying
out major pruning work in late Summer and Autumn.
Wiring In mid-summer though indoor trees can be wired mid-winter
particularly if out of leaf. Care should be taken as bark
marks easily. Healthy trees can also be defoliated during
Winter (if necessary) and mid Summer to enable easier wiring.
Propagation Sow seed outdoors in Autumn or Spring. Greenwood cuttings
in Summer. Hardwood cuttings in Winter. Air-layering
after spring growth has hardened.
Pests and
diseases Elm bonsai are not affected by Dutch Elm Disease
as the beetle requires the volume of wood only available to
it in fully grown mature trees. An attack (if it were to happen)
would easily be dealt with by systemic insecticides and fungicides
on a potted tree in comparison to the problems associated
with eradicating Dutch Elm Disease on a fully-grown tree in
the ground.
Watch for aphids,
leafhoppers and gall mites
Styles Suitable for all forms and sizes- especially good for the
broom form which replicates the natural shape of Ulmus.
