Boxwoods, with their small, evergreen leaves, make very nice bonsai subjects. They are also readily available from nurseries and garden centers in a variety of sizes. This article walks through the initial pruning and potting of an inexpensive boxwood to begin its bonsai training.

My recent scouting trip through a local nursery for promising bonsai subjects yielded a lovely little boxwood. This particular Buxus ‘Green Gem’ boasted some interesting above-ground roots – always an added plus when it comes to creating a bonsai. The three major branches forking off from the main trunk offered multiple styling options, including the potential for a nice slanting style bonsai. 

Both the size and cost of the boxwood were pluses as well. It was potted in a gallon container, which is a great choice when choosing nursery stock for bonsai. This size container yields a tree that can fit into inexpensive and readily available sizes of bonsai pots. The price, with tax, was just under $14. 

About the Green Gem Boxwood

The ‘Green Gem’ boxwood variety is a winter-hardy dwarf hybrid shrub. It produces a dense growth of foliage with evergreen glossy, oval-shaped leaves. In landscapes, it grows in a compact globular shape to a height and width of 2 to 3 feet. This boxwood makes an excellent low hedge and is perfect for adding year-round color to tight spaces in landscaping. 

This particular tree appeared healthy except that large portion of the foliage had a bronze cast to the leaves. The tree was not alone, as its fellow boxwoods in the nursery also exhibited this same bronze foliage.

A little research revealed that foliage bronzing during winter months is common in some varieties of boxwood, including ‘Green Gem’. Trees experiencing cold temperatures in conjunction with sunlight and wind often undergo foliage color changes. The bronze leaves usually regain their green color with the arrival of spring and warmer weather.

I knew that the initial styling would get rid of a large portion of the bronzed foliage. I decided to trust that whatever was left would regain its green color with the onset of warmer weather. If not, I could always trim more later.

Picking a Pot for the Boxwood Bonsai

After arriving home with the little boxwood, I sorted through my pot collection to find it a suitable home. I opted for a round, clay-colored drum pot.  I love the look of drum pots – their simple nail patterns add interest to the overall display without detracting from the tree. 

Choosing a round bonsai pot offered other advantages. Because this boxwood offered more than one good styling option, I decided that potting it first might make styling easier. The round pot gave me the flexibility to tackle the top growth after potting, knowing that whatever I settled on for the front view would work. This approach turned out to be a good move, as I’ll explain later. 

Keep in mind that when hobbyists need to make major reductions to both the top growth and roots of a tree, they normally style first and pot last. It’s okay to reverse the order as long as both operations happen back-to-back. Because roots support the top growth, both need to be trimmed in the same proportions. Never let top growth go untrimmed after a major root pruning, or the tree may not survive the stress.

Before tackling the task of root pruning, I prepared the pot by installing screens and anchor wires and added a small foundation of gravel and soil to the bottom.

Root Pruning and Potting the Boxwood Bonsai

When I removed the tree from its plastic nursery container, I found it had become quite pot bound. This is common with boxwoods, which tend to have very dense and prolific root balls. In cases like this, it works best to first trim off the densely matted bottom portion. Then, comb out and trim the remaining roots enough to comfortably fit the pot. 

When I started working the soil out of this very dense root ball, I feared the tree might require a bigger pot than the one I had selected.  I needed to avoid trimming off more than around one third of the roots at this initial pruning. Therefore, it was important to choose a bonsai pot that would fit the trimmed root ball without crowding. However, after thoroughly working out the roots, I found that the round drum pot tree fit the tree just fine.

After placing the tree, and securing it with the wires already in in the pot for that purpose, it was time to start adding soil. I added soil a scoop at a time and worked it in and around the roots with the chopstick. Eventually, all the roots were covered except the ones I wanted exposed.

After evening out the soil surface and carefully performing the first watering, the potting was complete. I was ready to style the little boxwood as a bonsai.

Styling the Boxwood Bonsai

I began the styling process by removing a number of branches and foliage from the bottom of the tree. This exposed the trunk and the lower part of the three major branches. I isolated the growth of each major branch with my fingers and hands to evaluate them individually. Doing this enabled me to get a better idea of how the tree might be shaped with that branch as the main leader. I also studied how removing all or part of each branch would affect the overall composition of the bonsai.

A Styling Dilemma

Upon evaluating this little boxwood, I found myself in a bit of a quandary. Two of the three major branches offered good options for styling, and all three had definite pros and cons:

• The middle branch afforded a nice, straight extension of the trunk with good taper. My preference was to have this branch serve as the main leader and make a slanting style bonsai with a dramatic slant angle. Unfortunately, the middle branch was the most sparsely foliated of the three. It would take some time for it to fill out and look nice if I cut back the other two branches.

• The branch to the right of the middle had the thickest trunk of the three and grew in a more upright manner than the middle branch. This branch would also work well as the main leader, yielding a bonsai with a more subdued slant. The downside of this choice was that the foliage for the front view was underdeveloped. Like the middle branch, it would require some time develop an attractive look.

• The branch to the left of the middle was the thinnest of the three. My instinct was to cut it back severely or remove it entirely. However, it happened to have the nicest, most evenly distributed foliage of all the branches.  

I started trimming and shaping the foliage to open up the tree a bit before choosing how much of each main branch to remove and how much to keep.

Now, I will admit that I’m guilty of being overly conservative when it comes to trimming back my trees. Most, or at least many, bonsai hobbyists wouldn’t think twice about removing the thin left branch completely and cutting off or trimming back one of the other two. Most like to trim hard, then wait for the tree to grow out over time. 

A Change of Direction 

I, however, ultimately decided to keep all three of the main branches – at least temporarily. I did this because my original styling plan wasn’t working out as well as I had hoped. From my preferred front view, with roots on the left and tip on the right, the foliage on both the main branches looked underdeveloped. I found that the tree presented more attractively when viewed from the reverse angle, with roots on the right and tip on the left.

I decided to go with the more appealing view as the front of the bonsai for now. Because I had chosen a round pot, this switch was easily accomplished with a half-rotation of the turntable! I also chose not to remove that thin left-hand branch with the nice foliage quite yet. With the new viewing angle, that branch is in the forefront and it contributes to the attractiveness of the tree.

To finish the initial styling, I wired one of the smaller branches located in the back to redirect its growth. During the upcoming growing season, I’ll look to further open up the foliage and refine its shape.

I’m hoping the tree will fill out nicely on the current back view over the next couple of years. When I restyle, I expect to choose one of the two thicker branches to be the main leader. This will allow me to reverse back to my preferred front view. But in the meantime, I still have an interesting and attractive little boxwood bonsai to enjoy year-round!

In the practice of bonsai, it’s always helpful to choose nursery stock wisely and keep an open mind when styling. By doing both those things, we transformed an inexpensive boxwood shrub into a respectable starter bonsai. This tree has potential to be further developed and refined over time into a nice slanting style specimen.