Ulmus crassifolia is a deciduous tree native to south-central North America, including Texas, Louisiana, and neighboring states. It is a member of the Ulmaceae family of plants and is commonly known as the ‘Cedar Elm’. It thrives in valleys with flat bottoms because the conditions are ideal for growth.

The trees grow to 90 feet (ca. 27 m) in height and are known for their rounded crown foliage structure. Apart from this, the leaves are quite small and will grow up to 5 cm in length and 2 cm in breadth. They are distinguishable thanks to the broad base which tapers gradually to the top. Moreover, the leaves change into many beautiful colors throughout the year and will fall in early winter.

An interesting fact about the Ulmus crassifolia is that the largest trees can sometimes grow much taller. For example, the currently known largest tree in the species is 37 meters high and was measured in 2001. It grows in Tennessee and is 10 meters taller than most Ulmus crassifolia trees.

As for rowing Ulmus crassifolia trees into bonsai, the best specimens are often found directly in the wild. This is often due to various natural reasons such as wildlife or cattle which keeps the tree small in its natural habitat. So, due to this, these trees are gaining popularity and can be found quite easily.

This article will help bonsai enthusiasts understand the Ulmus crassifolia Bonsai Tree better.

How long does it take to grow Ulmus crassifolia Bonsai?

Bonsai of Ulmus crassifolia are slow growers, with a ten-year minimum anticipated complete growth time. This is the amount of time it will take the seed to mature to the point where it can be cut. That being said, this is just an estimate and the exact amount of time for growth varies depending on elements like temperature, water, and so on.

Let’s go into the specifics about how to plant, care for, and grow your Ulmus crassifolia bonsai to help you out.

Position and lighting

As long as it is not too hot, Ulmus crassifolia bonsai grow in full sun or semi-shade. They can endure morning temperatures in the summer and spring but should be taken into the shade in direct daytime sunlight. Aside from that, you should bring your bonsai indoors during winter as extreme temperatures and frost are very harmful to the leaves and branches.

Temperature requirements

The tolerant nature of Ulmus crassifolia bonsai is one of the reasons they are so popular as bonsai. These trees can tolerate a wide variety of temperatures and will thrive as long as extremes of heat or cold are avoided. Most notably, they are hardy to zone 6 and will grow well in these conditions.


Because the Ulmus crassifolia bonsai is not difficult to grow, you can use most types of soil with it. However, for optimal growth, slightly acidic soil with a pH of 6 is recommended.

Watering needs

Water is required in moderate amounts by Ulmus crassifolia bonsai, and too much or too little might be detrimental to their growth. Looking at the soil is the best approach to figure out when to water your Ulmus crassifolia bonsai. If your soil is starting to dry out, water it until it is moist. If the soil is damp, however, wait until it dries before watering, as this might cause root rot.

While it’s crucial to keep the correct amount of water on hand, the Ulmus crassifolia bonsai won’t require much attention. This is because they are extremely hardy, and a few mistakes will not have a significant impact on the growth of your tree.

Depending on the weather and season, the amount of water you should use differs as well. Water your bonsai once every 1-2 days during the spring and summer months to keep it healthy. This changes in the winter, and you can lower your watering frequency to once every three days because your tree will use less water.

Misting is something else to keep in mind. This entails lightly sprinkling your bonsai’s surface with misted water. This will help to improve the foliage of your tree as well as its overall health. However, it should not be used as a substitute for watering and should only be used as a supplement.


Fertilizing your bonsai is essential because it grows in pots and may not receive all the nutrients it needs naturally. So, for Ulmus crassifolia, you can use any organic fertilizer that has been diluted to half strength. During the spring and summer, fertilising should be done monthly, and during the winter, it can be skipped.

How to Plant and Grow Ulmus crassifolia Bonsai

You’re interested in learning how to cultivate and care for Ulmus crassifolia bonsai. Awesome! Let’s take a closer look at how to cultivate and plant your own Ulmus crassifolia bonsai.


These bonsai are quite easy to propagate and can be done with various methods such as seeds, cutting, air layering, etc. They will adapt to most styles and grow well. That being said, these species already grow various new buds from their trunk so grafting is often not necessary. It is much easier to pinch the new buds for growth reduction.

Pruning and wiring

Pruning is a crucial aspect of creating a stunning bonsai of any species. It entails trimming and cutting outgrowths to keep your bonsai’s size and shape small. While the Ulmus crassifolia bonsai is a slow grower, it does grow throughout the year making trimming quite necessary.

When trimming, make sure you avoid older branches to avoid stressing your bonsai. It is important to keep a steady hand and pull back the further outgrown nodes and growths. This will not only reduce the burden on your bonsai but also improve its overall appeal.

Wiring is also a bit tedious with the Ulmus crassifolia bonsai. This is because long wiring can often stunt your bonsai’s growth and sometimes even leave marks on the bark. So, make sure to keep the wiring loose and take it down within 3 months.


Repotting is another important process when it comes to growing a bonsai tree. It is quite straightforward and only involves a few steps. Begin by removing your bonsai from its pot, as well as all the surrounding roots and soil. After that, clip the surplus roots with trimmers, being careful not to cut central roots. After that, you may re-pot your bonsai and fill up the space with new soil. This aids in acclimating your bonsai to its smaller size while also enhancing its appearance.

When it comes to the Ulmus crassifolia species, you should repot the trees every two years when they are young. Following this, progressively lower the repotting frequency as they get older. These plants require repotting because their roots become entwined and begin to grow outside the closed root system.

Some things to remember are that repotting should be done in the spring and that you should take special care of your bonsai afterwards. This entails using organic fertilizers and plenty of water to ensure your bonsai receives the nutrients it requires to thrive.

Image Source

How to Care for Your Ulmus crassifolia Bonsai

During their early years, Ulmus crassifolia bonsai should be kept out of extreme hot or cold temperatures. They do, however, grow well up to zone 6 and can be kept outside. Any standard mix with a PH of around 6 would suffice in terms of soil.

To keep the soil moist, it should be irrigated and misted on a regular basis. When it comes to repotting, these bonsai should be repotted every 2-3 years when they’re young, and then more frequently as they get older.

Ulmus crassifolia bonsai should be grown in semi-shade or full sun for best results. Keep them away from direct sunshine and cold air, since these conditions can cause them to burn or develop frost.

Pests & Diseases

Pests and diseases are a common problem that is faced by all kinds of bonsai and trees alike. These ailments can latch onto your bonsai and drain them of their nutrients leading to fatal issues. That being said, the Ulmus crassifolia isn’t the most prone to such issues and you won’t have to be too bothered. That said, let’s cover some of the most common pests and diseases that can affect your bonsai –

  • Red Spider Mites – These garden pests can be found in a wide range of plant types and species all over the world. Infected bonsai will begin to display indicators of the pest, such as a lack of coloration or limping branches. When it comes to treating an infestation, you can use diluted pesticides and insecticides to kill the pests and keep your bonsai safe.
  • Scale – Scale are small insects that cling to the undersides of your leaves and drink the inside juices. They can be highly detrimental to your bonsai, so get rid of them as soon as possible. You can do this by using insecticides and removing them one by one with a brush or pick.
  • Mildew – Mildew is a type of fungus that can start growing on the moist leaves and branches of your bonsai tree. To avoid this, make sure to keep the humidity and moisture levels in check. This is because increased humidity and heat can lead to faster growth of mildew and stunt your tree’s growth.