One of the most attractive bonsai trees is the Chinese Elm, Ulmus parvifolia. Its gorgeous twisting trunk, small green leaves, strong branches, and fine twigs make it an excellent specimen.

Among the main attractions of a Chinese Elm bonsai tree is its beautiful contrast between the thick, sturdy trunk and the delicate, thin branches. Chinese elm bonsai are extremely popular, especially among beginners.

Moreover, Chinese elm bonsai is very easy to care for and even more stunning to look at. The bonsai tree thrives well in warmer climates, where the leaves remain a magnificent shade of evergreen.

So, let us learn in this article how to care for the Chinese elm bonsai trees in detail.

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Chinese Elm Bonsai Care

Watering

Simplified Watering Rules: Water the Chinese elm bonsai every alternate day during summers and once in 3-4 days during winters.

Thumb rule of watering: Check the top soil of the bonsai and it feels dry, you should water it generously with 1-2 litres of water to soak the root balls completely. Then leave the plant and water it again when the soil goes dry.

Make sure to check the soil moisture. When moisture is one inch into the dirt, the bonsai tree doesn’t require any additional water. A great way to check soil moisture is with the help of a chopstick and insert it into the soil (no deeper than 2 inches).

Placement

The Chinese elm is a semi indoor bonsai that grows in full sun as well as partial shade. It can be placed outdoors in temperate climates. However in colder months, you must bring it inside a well lit room or the shades.

If you have indoor Chinese elm bonsai, you can place it outdoor during the summer. But it is always best to bring the bonsai into a cool, frost-free room in winter. Though this bonsai plant can endure some frost, it differs depending on the region it is imported from.

The tree species from northern Chinese regions are mostly frost-hardy compared to southern areas. Depending on the winter temperature, they may drop the leaves. Consider keeping them until spring when the new shoots emerge.

In Short: Keep the Chinese Elm Bonsai tree in partial shade into your balcony and it will thrive.

Fertilizer

Use any balanced fertilizer like NPK 19:19:19 twice a month during growing season like Feb to May and then once a month.

Provide plenty of fertilizer to nourish your bonsai tree during the growing season. There is no need to use any fancy fertilizer; solid organic fertilizer and well-balanced liquid fertilizer work great.

Also, there is no need to feed the Chinese elm bonsai in cold winters when it is dormant.

This plant does not require a high level of nitrogen in the fertilizer. A low nitrogen-based fertilizer works best.

If you want your Chinese elm bonsai to have larger leaves, purchase a high nitrogen fertilizer.

If your tree looks weak, for example, losing leaves (when it should not be) or colour fading, then use hormones and vitamins to strengthen the bonsai tree.

Adding more fertilizer during this period is not beneficial. After giving the Chinese Elm vitamins and hormones, you should wait approximately two weeks.

When new growth sprouts, once again, start using fertilizer.

Overwintering

The Chinese elm bonsai can withstand very cold temperatures. Unheated foil tents can handle temperatures of -5°C without any problems. 

A warm, dark cellar is not appropriate. Instead, choose an unheated garage or a cool staircase.

Pruning

Once or twice during the growing season, it is recommended to prune the Chinese Elm bonsai tree. Usually, it’s best to prune the bonsai tree before or after repotting. Also, the roots of the bonsai tree must be pruned, so they do not strain when trying to get nutrients.

Before pruning, allow the shoots to extend 3-4 nodes, then return them to 1-2 leaves. After heavy pruning, the tree buds grow well from old wood.

The best time to prune Chinese elm bonsai is late autumn, especially on larger branches. Moreover, the bonsai plant is ideal for shaping with standard wiring and guy wire techniques.

Wiring

A well-maintained Chinese elm bonsai can only be kept in good shape with pruning. But by wiring the branches, you can influence the shape and quality of the bonsai.

If you want to wire Chinese elm bonsai, keep it cold in autumn so that the leaves are thrown off. This makes it easy to attach the wire. This bonsai throws off its leaves at the latest after the first night of frost.

One to two-year-old shoots and branches are easy to wire and bend into shape. Wrap the wire around the branch at an angle of 45 degrees, and then bend the shoot to the desired position.

Gently stretch the stronger branches with thin wire while giving a new shape; otherwise, its wires would leave traces in the bark too quickly.

If the wire gets pressed into the bark, remove the bonsai wire. It is best to rewire immediately if the branch does not maintain a secure position if required. As the tree bark is soft, it is best to use aluminum wire instead of harder copper wire.

Repotting

It is crucial to re-pot it regularly to prevent Chinese elm bonsai from becoming pot bounded. A tree becomes pot-bound when the roots grow to the size of the pot and fill it. If the root does not get enough space to get nutrients from the soil, the tree will stop growing.

While re-potting the bonsai, it is good to trim the roots so that they can supply nutrients to grow and flourish.

The suitable time to re-pot the Chinese elm bonsai is early spring, while it is dormant after winter. During this time, the tree will be budding but not covered in foliage, so it is ideal for minimizing the damage or any shock that will affect the plant while re-potting it.
Step 1: Gather the re-potting tools such as a root rake, wire cutter, scissors, and chopsticks.

Step 2: with the help of a root rake, carefully remove your tree from its pot. Now check the roots to see if repotting is required. If you see roots circling and filling the pot, it is time for repotting.

Step 3: Take the chopstick and remove the old soil. Gently comb the roots, starting on the sides and moving to the bottom until all the old soil is removed. Avoid damaging the root system.

Step 4: Use scissors and cut away 30 percent of the roots. Cutaway long roots and prune them to balance the tree’s growth.

Step 5: Decide whether you want to keep your tree in the same pot or move it to a bigger pot. If you are using a new pot, cover the drainage hole with mesh and attach the wire to anchor the tree to the pot.

Step 6: Put a thin layer of heavy-grain soil for good drainage. Lava rock, grit, or Akadama will also work. Next, add a thin layer of specialized bonsai soil.

Step 7: Plant the tree in a new pot. Use the wire you attached to the pot to anchor the tree. Arrange the roots to get enough space, and add bonsai soil.

Step 8: Use a chopstick to work on the soil to eliminate any air pockets around the roots. Make sure to put enough soil to cover the roots of the tree.

Step 9: Water the bonsai tree well, as watering regularly is important to keep the bonsai healthy. At the same time, it is important not to overwater, and it should not become waterlogged. If you neglect this, your tree will die.

Step 10: Chinese elm requires watering every second day to give the soil time to dry a little in between.

Insects / Pests and Disease

When Chinese elms are not in perfect health, they are more susceptible to pests and diseases. Spray regularly with a contact insecticide applied to both root and foliage. Applying treatments to roots is useful because it gets spread throughout the sap streams to all areas of the plant.

A poorly maintained plant is more likely to be infested by pests and suffer from mildew, rust, and black spots. You can control this by ensuring that you treat your plant with a liquid fertilizer that contains elements such as magnesium, manganese, iron, and zinc. 

Lack of these nutrients causes leaf discoloration, stunts leaf growth, and increases susceptibility to disease.

1. Fungus Infestation

Several types of fungus affect the general health and appearance of the Chinese elm bonsai. Leaf spot is a common problem often caused due to overwatering. If too much water remains on the leaves for a long period, it causes leaf drop.

This problem can be addressed by limiting watering to the morning so that it can dry out during the day.

 Black and Brown Spots can usually be addressed through a fungicide.

Rust is caused due to fungal propagation of spores on the underside of the leaf. This can be controlled by removing the affected leaves and applying fungicide. Additionally, ensure that there is adequate air circulation around the plant.

2. Mildew

Powdery mildew grows in damp conditions, and poor air circulation stimulates growth. You can notice a white, powdery mould on the leaves where they are present. They extract the sap from the Chinese elm bonsai and affect its general health and appearance.

Moreover, they are highly resistant to fungicides. Tropical fungicides can help, but it is best to trim back the affected leaves.

3. Root Rot

Overwatering causes the yellowing of leaves and the dropping of many leaves to conserve resources. Both overwatering and underwatering cause the root system to become damaged. So, ensure proper watering for Chinese elm bonsai.

4. Aphids

Aphids such as blackflies, greenflies, and whiteflies can cause damage to the bonsai. Aphids suck on the plant sap and reduce the number of nutrients available for proper growth. These aphids also leave sugary excretions called Honeydew.

Often aphids are herded by ants. Moreover, they block the sunlight and reduce the resistance to disease, leading to weaker plant growth. An insecticide may be required, or you can gently wash the leaves with a mild detergent and wipe them down.

You can also manually remove the aphids by simply using tweezers.

5. Scarid flies

These flies are a common problem for house plants. Scarid flies are greyish-brown flies and have white larvae that live on the soil’s surface. Do not overwater the soil, and these flies will disappear. If you find Scarid flies annoying, spray them with bonsai-friendly insecticide.

6. Red spider mites

Red Spider Mites are too small to be seen with the naked eye; they produce web-like structures and are often found on the upper leaves of the Bonsai. An insecticide can sort out this problem.

7. Mealybugs

White Mealy Bugs look like small wood lice. They feed on sap and stunt the growth of trees. Leaf colour can also change. Usually, an insecticide soil drench will prevent them from causing further damage to the Bonsai.

8. Scale insects

Ladybugs eat scale insects as prey, but if there are no predators to eat them, then an insecticide soil drench can be helpful; however, there have been reports that this treatment is not as effective as it once was. Picking them off by hand is another option.

Propagation

Mostly Chinese elm are propagated using stem cuttings from a “mother” plant. 

Step 1: Take a semi-hardwood cutting from a healthy Chinese elm during summertime or between July and September. The wood should be partially mature, not necessarily green, but flexible.

Step 2: Sterilize a pair of sharp garden shears with rubbing alcohol and cut directly below a leaf node.

Step 3: Leave the cutting in water and prepare the rooting medium. Fill a 10-inch pot with peat moss or a mix of one part peat moss to one part vermiculite or perlite. Now poke your finger into the center to make a 3-inch-deep hole.

Step 4: Pinch off the leaves from the cutting. Dip the cutting in the rooting hormone and slide the cutting into the hole you created earlier.

Step 5: Water the pot until the rooting medium is moist. Roll the sides of the plastic bag down and place the pot in the bag; roll the sides up and close the top of the bag with a twist tie or rubber band. With a razor blade or utility knife, make 5-10 slits.

Step 6: Put the pot in a warm room under indirect sunlight. Open the bag every day to mist the cutting and reseal it after watering. Repeat this process for 8-10 weeks.

Step 7: Check the roots by pulling the cutting; if the cutting sticks to the soil, the roots have been formed.

Common issues with Chinese elm bonsai:

Chinese elms are easiest to grow as bonsai, but that doesn’t mean they are free from issues. But the good thing is those issues can be curable. Let’s talk about those problems that your Chinese elm bonsai can face and how to solve them;

Yellow leaves:

Generally, yellow leaves emerge when the Chinese Elm tree doesn’t obtain sufficient sunlight. You might have put the right amount of fertilizer, and water, and maintain its air circulation, but when it doesn’t get sufficient sunlight, it can show the signs through yellowing leaves. 

Solution:

To tackle this problem, first, you’ll have to re-adjust the bonsai’s humidity, whether it is indoor or outdoor. A balance of good humidity and sun exposure will ensure the ideal condition. If you continue to do this accurately, it should only take a few weeks to months for the bonsai to grow lush green leaves again. 

Drowning issue:

This issue occurs when you put in too much water and the soil is retaining moisture for too long in your pot. Too much drowning in moisture can be responsible for the bonsai bark rot and discoloration, as well as dry leaves. 

Solution:

Handling this issue is relatively easy, make sure to use quick-draining soil and give the bonsai water only when the upper part of the soil is dry.

Dutch Elm Disease:

This is a kind of fungal infection that will harm the upper branches of the Chinese Elm tree, forcing the leaves to turn yellow and ultimately die during summer. As you might have seen, this initial sign is rather identical to the yellow leaves problem above when the bonsai didn’t get sufficient light.

So to differentiate, you should check whether there are spots throughout the bonsai besides this initial sign. 

Solution:

You should use fungicides to cure this problem. You can also prune the bonsai and expect the disease to stop. Make sure you hold the infected branches sealed when you get rid of them, so they won’t spread to other branches.

Although Chinese Elm is relatively immune to diseases, always check the bonsai regularly to see whether it is infected or not. The earlier you detect its issue and the earlier you take steps for the bonsai, the longer the tree will live. 

Canker Disease

One of the most common signs of this disease is fading color on the leaves, as well as imperfect maturation. Another possible sign is shown in the swelling of the barks, and this issue usually happens after pruning.

Solution:

When you see these signs, mainly just after you prune your bonsai, the first thing you should do is to separate the tree, cut out the affected area, and apply a wound paste over it.

FAQs

1. Can Chinese Elm Bonsai be kept indoors?

The Chinese Elm is a semi indoor bonsai which can be placed in the full Sun or Partial Shade. If you plan to grow the chinese elm bonsai indoor, consider placing it in the very well lit area of the room and keep it in the balcony once a week.

2. How long does a Chinese elm bonsai normally live?

A Chinese elm can live anywhere from 50 to 150 years with proper care and growing conditions.

3. How much Sun does the Chinese elm needs?

Chinese elm requires a full sun so avoid keeping them in the dark corner. Indoor Chinese elm needs plenty of light, so that a bright sunny windowsill can be an ideal place.

4. How often should I prune the Chinese elm bonsai tree?

Chinese elm is a very robust and vigorous bonsai tree. A Chinese elm grows in summer about 15cm per month with optimal care. For this reason, they usually have to be pruned three times a year.

5. Do Chinese elm produce flowers?

The Chinese elm blooms in early fall and dies in late fall, becoming a disc-shaped samara that is brown.

Conclusion

Chinese elm bonsai are very easy to care for. The Chinese elm tree is a perfect bonsai tree despite its robust nature.

Bonsai of this nature tolerate the widest range of site conditions (temperature, light, and humidity). 

They are suitable to grow under indoor conditions. Chinese elm’s heavy pruning tolerance makes them an ideal choice for a beginner. 

To grow a healthy Chinese elm bonsai, keep it in a warm place and good moist soil. Prune, train and repot the plant only when needed.

We will be happy to know how you take care of your precious Chinese elm bonsai; please let us know in the below comment section.

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