How To Care For Your Seiju Elm Bonsai Tree

Ulmus Parvifolia 'Seiju' Bonsai Care

About The Seiju Elm Bonsai Tree

Seiju Elms are a strong and adaptable bonsai tree that make a great tree for beginners.  They develop a lot of character in their bark, and take well to shaping, making them favored among the bonsai experts as well.

The Seiju Elm is native to East Asia, where it can grow up to 60 feet in its natural state.

Seiju is a specific cultivar that was bred grow quicker, produce late summer flowers, and stay smaller overall (including the remarkably petite leaves.)

This tree has a unique ability among bonsai trees to thrive either indoors or outdoors, although it may drop some of its leaves in either situation since it is semi-deciduous. Seiju Chinese Elms form a graceful upright rounded canopy with small, dark green leaves. 

All in all, this makes a wonderful and traditional bonsai tree.

One of the advantages to growing a Chinese Seiju Elm bonsai tree is that, unlike many other elm trees, it is not prone to Dutch elm disease -- which can be fatal.

Placement

A Seiju Elm makes a wonderful indoor bonsai with enough lighting.  It can live outside, but will die in temperatures below 45 degrees unless it's incredibly well protected and insulated - so inside for the winter is best.

Make sure it gets plenty of sun (6 hours or so) with a quality grow light when indoors, or on a windowsill (south facing preferred.)

Bring it inside for the season when the temperature is reaching 40 degrees, and bring it out when all chances of freezing for the season are gone.

Watering

The Seiju Elm, like most bonsai trees, will die if it dries out.  It enjoys plenty of water in well draining soil. Never let it dry out completely.

Humidity

When your Seiju Elm bonsai tree is indoors, using a humidity tray is recommended.

Fertilizing

Since your Seiju Elm bonsai is in a small pot, and not the ground, it needs nutrients.  A slow release (pellet based) fertilizer is perfect for this, and can be added sparingly every 1-2 months during the growing season.

Pruning & Trimming

Trim back the new growth to the farthest safe point that looks good to you — but never remove all of the new growth.

A regular trim will help keep your Seiju Elm bonsai tree short, while helping the trunk grow thicker.

Repotting

Repotting must be performed periodically on your bonsai, Seiju Elm included, when its root system has filled the pot.  If you can clearly see the roots coming out of the bottom of the pot, it’s time to repot your bonsai.

Generally, this means every 2-3 years for a deciduous tree and every 4-5 years for an evergreen.  Being somewhere in between this, the Seiju Elm will need to be repotted around every 3 years depending on its environment.

Repotting should be done in mid-summer, when the tree is at it’s least fragile state.

Your Seiju Elm bonsai, along with all of its soil, should be removed from the pot.  From there, you can trim away no more than 1/3rd of the root mass (1/4th is preferred.) 

Then you can repot the tree in the same pot, or give it a newer / bigger pot to thrive in.

After repotting, your bonsai Seiju Elm should be thoroughly watered.

Diseases, Insects & Other Pests

Your Seiju Elm bonsai can be treated for pests like a normal Seiju Elm tree.  Just remember, your tree is miniature and will need a much smaller and more gentile dose of treatment.