Chinese Elm / Ulmus parvifolia are by far the best selling and most popular bonsai tree sold in the UK at the present time, and as such represent most people’s foray into bonsai.
They are available in many sizes from about 7cm tall up to about 1m or more, and can reach extremely mature ages. A small mame sized Chinese elm may be only a few years old, whereas a specimen bonsai of a metre or more may be upwards of 100 years old.
They exhibit craggy bark with deep fissures which deepen as the tree ages, fine twigging and ramification and perfectly sized leaves of 5-15mm in length, depending on the variety. There are many varieties available, but mostly sold under the generic name of Chinese Elm. Some interesting varigated varieties occasionally show up for sale and are readily purchased. If Chinese elm bonsai are kept indoors (in the UK) they will stay evergreen, if they are kept outdoors then they will become deciduous. Personally I prefer to keep my bonsai trees outdoors, so any Chinese Elm we have for any length of time will be deciduous, provided they have experienced an Autumn and been subjected to a frost or two before the really cold weather sets in then they are hardy to about -10 deg C.
Care of Chinese Elm is reasonably straightforward, watering on a daily basis throughout the growing season, ensuring the soil never completely dries out. During the dormant season they should be allowed to stay moist, but protection from the elements to avoid waterlogging is essential as they do not tolerate overwatering and are prone to shedding thier leaves when over wet or too dry.
Fertilising should be carried out on a fortnightly basis, using any of the proprietary fertilisers availabe at www.bonsaiuk.co.uk , at half strength if possible as I believe ‘little and often’ is better than any other method.
Pruning of the shoots should be carried out as and when required, allowing the growing tips to extend to approximately 8-9 leaves each time will allow the tree to build up some vigour and prepare it better for the winter if kept outdoors. They respond well to hard pruning, and many overgrown Chinese Elm bonsai are restored using this method, as they readily sprout from old wood as long as the tree is inherently healthy.
Repotting should be carrried out every 1-2 years, using a well balanced soil mix that allows free drainage and some stability for the tree.
Chinese elm are available here