The Chinese Elm or Ulmus Parvifolia is a native to China, Korea, and Japan. They feature a smooth trunk texture with bark than can begin to peel away as it ages. The foliage of the Chinese Elm is small and compact with a very distinctive diamond shaped leaf with small serrated edges. These leaves give the elm its own very unique character. The elms are also rigorous growers that tolerate many different types of climate including very hot and dry climates while still being able to thrive in more humid conditions as well.
They are one of the easiest and most used species of trees for bonsai for many reasons including forgiving watering requirements, simple lighting, easy pruning, and tolerance of aggressive root work.
Lighting
Chinese Elm Bonsai trees thrive best with natural sunlight. We recommend filtered natural sunlight. Full sun can lead to slight leaf burn if conditions are too hot. Chinese elms in smaller pots will need to be protected from harsher full sunlight. However, trees in larger pots enjoy full sun conditions. Lighting is essential to the growth of foliage on all trees including the Chinese elm. Dense growth will impede the growth of new buds. Therefore, it is important to prune back your elms regularly to thin out foliage and let in light. Foliage and branches will begin to wilt if outer branches prevent light from penetrating through.
Watering
Chinese elm trees are very forgiving to late and missed waterings. However, continued missed waterings will cause the tree to stress and will eventually kill the tree. Chinese Elm Bonsai require moderate watering. Daily waterings are best during the hotter seasons. Moisture should always be present in the soil and should not be dry. We recommend using a soft spray to soak the soil. Ensure that water penetrates not only the topsoil but also into the roots by checking that draining is occurring on the bottom of the pot. To do this, watering your tree thoroughly once, then repeat again 5 minutes later after the initial watering has penetrated the topsoil. On the second watering, the water will seep further into the soil and into the roots. This process can also be repeated a 3rd time for best results.
The quality of your soil mix and climate will impact your watering requirements. Depending on your soil quality, your tree may require more frequent waterings (faster drainage) or less waterings if you live in a more humid environment. To learn more about soil mixes, we recommend watching our video on soil mixes.
“Chinese elms are rigorous growers that tolerate many different types of climate including very hot and dry climates while still being able to thrive in more humid conditions as well. “
Fertilizing
Chinese elms are vigorous growers and push buds and foliage out quickly even without fertilizer as long as light requirements are met. However, fertilizing can help your tree grow much quicker as well as help it protect itself from insects, pests, and diseases. Slow release granules work extremely well with Chinese Elms. Once placed on your the topsoil of your tree, the granules will slowly dissolve with every watering. The fertilizer granules will break apart and provide nourishment to the tree’s roots over time.
Once the granules or tablets have dissolved you can add more to continue feeding your tree. We recommend feeding your tree from Spring to Fall, scaling back during the Winter. Follow the instructions for the fertilizer to prevent overfeeding and burning of foliage. Over fertilized trees are at risk of burned leaves and possible death if used incorrectly.
Remember that if your tree is in recovery for other reasons such as pests or underwatering, do you use fertilizer until your tree is no longer stressed. Fertilizing a sick tree may cause it to die.
Temperature Requirements
Chinese elms can survive in a variety of climates including hot and dry conditions as well as tropical humid climates. The elms also can handle colder invironments as they lose their leaves during the winter period as they go into dormancy.
Chinese elms can not handle extreme cold temperatures. We recommend bringing them in for protection during cold, snowier climates. During the dormancy period, the Chinese elm will not grow. Once spring arrives and the weather begins to warm, the Chinese elm will begin to sprout new leaves.
Pests & Diseases
Chinese elms are easily susceptible to fungus gnats and aphids. To prevent insects from harming your tree, we recommend preventive spraying with the use of neem oil or year round oil. Applying this before the active spring insect season will prevent outbreaks. However, they can also be killed with Neem oil or simple diluted household dish detergent. The key to stopping the cycle of bugs is to spray 7 days after the first application. This will eliminate any newly hatched eggs.
Fungus issues can be a problem in cooler damper environments. If you see a layer on the surface of your trunk or branches, you may have a fungus issue. Proper air circulation will correct this issue. However, fungicides can also be used to kill the fungus.
Remember: Healthy trees will naturally fight away pests and diseases as well so keep your tree well hydrated and fed and your tree can natural fight away issues on its own.
Pruning and Training
Training and pruning your Chinese elm is what makes the Chinese elm so enjoyable as a bonsai tree. With only the use of a shears, you can easily train your tree using the simple clip and grow method. (Click here to watch a video on Pruning your Chinese Elm). As the foliage begins to grow out, you can trip back to 4-5 leaf pairs to begin the ramification process. This not only forces your tree to start branching out in different directions but also thins out your foliage to let in light.
By using the clip and grow method, you’ll be able to create full pad layers on your tree as well as develop ramification on those pad layers. For advanced artists, you can also trunk chop a Chinese elm bonsai to start from scratch and develop a new set of branches from new foliage buds.
Repotting
Chinese Elms can be repotted during spring and fall for highest success rates. Avoid winter repotting as colder temperatures, as once the tree enters dormancy, the tree’s roots will not grow making it more difficult for recovery. During repotting, we recommend trimming off older roots to promote new growth. Repot your elm as the tree outgrows the pot. Depending on the growth rate, this can be every 2-3 years.
For more details on repotting your Chinese Elm bonsai tree, view our video here.
“Training and pruning your Chinese elm is what makes the Chinese elm so enjoyable as a bonsai tree.”
