Making Bonsai from nursery stock is a means to many ends. It's the least expensive way to
enter into a sustainable, lifelong bonsai practice. It's also quicker than growing bonsai from seed. You'll learn a great deal about horticulture, bonsai design, care, and maintenance by buying a nursery stock specimen. The trees (or shrubs) you buy from the garden center are plentiful and inexpensive compared to high-quality, refined bonsai. With the right method, appropriate amounts of sweat-equity, and a little patience, you can have a beautiful bonsai in just a few years.
Species
Local greenhouses sell a wide variety of healthy tree specimens, of all different sizes, that will all flourish in your local climate. You will find several species that are adaptable to life as a bonsai, including but not limited to: Spruce, Juniper, Pine, Hinoki Cypress, Boxwood, Azalea, Bougainvillea, and Flowering Cherry. The aforementioned species can all be chopped, pruned, wired, and made into a bonsai in a relatively short amount of time using the current growth on the tree, as compared to deciduous species. (Note: I have purposely omitted Maples and other popular deciduous varieties. Because they take much longer to train as bonsai, due to the clip-and-grow timeline of refinement, they are beyond the scope of this article.)
Spruce
Common forms of Spruce include: Dwarf Alberta, Black Hills, and Colorado Blue Spruce. Spruce make great formal upright bonsai (think: Christmas tree), slanting trunk bonsai, twin trunk, and forest plantings, but also, with the right technique they can be turned into cascade and deadwood style bonsai. These trees are quite thirsty compared to juniper.
Juniper
Juniper can have a variety of foliage types and colors, and in winter, they can turn bronze, tan, or purple, regaining their green vigor in the spring. Common juniper for bonsai at nurseries include: Juniperus Horizontalis, Procumbens Nana (Japanese garden juniper), Sargent, Mountain juniper, and Chinese Juniper. San Jose juniper is harder to find, but also makes fine bonsai. Juniper can be trained into any conifer bonsai form, although they are less commonly styled as formal upright bonsai. They look great with deadwood features, from large deadwood branches and trunks, to small Jin and Shari effects. Deadwood effects mimic the violence and relentlessness of nature, from lightning, wind, and fire, to rain, ice, and snow. The dense, lush, mounding foliage of Procumbens Juniper lends itself naturally to traditional bonsai styling, whereas the lacy, hanging foliage of Sargent and Chinese juniper allows for lots of negative space and more easily visible trunk and branch lines. Some varieties of juniper like drier soil than others, but none like it too dry.
Boxwood
Boxwood (buxus) come in a wide variety of names, but all have rather small, thick, dark green leaves and eye-catching wrinkly, fissured bark from a young age. Boxwood can be styled as a lovely broom style, informal upright, twin or multi-trunk, and even cascade. These broadleaf evergreens are cold-hardy, and sport sweet-smelling “flowers” for a few weeks in springtime. In winter, leaves can turn a burnished red or orange, returning to bright emerald green in spring.
Pine
Pine trees commonly found at nursery centers are often Japanese Black Pine, Red Pine, and Mugo Pine. More experienced bonsai practitioners have success with the Black, Red, White Pine varieties - working with them can be challenging for beginners. Mugo Pine can be a bit more forgiving and are often available as smaller and less expensive trees. Pines must be worked slowly, as too much design advancement at once (within one growth period) can severely weaken, or even kill the tree. It’s best to proceed with caution and adhere to the old Pine bonsai rule-of-thumb, “one major insult per growth cycle”. Mugo pines, as a guideline, are thirstier than all other pines.
Hinoki Cypress
Hinoki Cypress is a great tree for bonsai. In layman’s terms, it is a “false-cypress” and is more like an eastern cedar tree (arborvitae) than a true cypress. The foliage is lush and develops into thick whorls, so regular pruning and pinching are needed throughout the growing season to keep the bonsai design. Hinoki Cypress bonsai prefer moist but not damp soil. Because of the upkeep during the growth cycle, these bonsai require more care than others. As bonsai, Hinoki Cypress can be styled in many different ways, but because they are often grafted onto stronger rootstock, it is difficult to find one that doesn't have a large, swollen graft area.
Azalea
Azalea are a popular choice for bonsai because of their gorgeous flowers. Nursery stock Azalea for bonsai are available, but it can be difficult to find suitable material. They prefer more acidic soil, usually a kanuma and pumice blend (We've got Flowering Blend bonsai substrate for sale in our shop).
Bougainvillea
Bougainvillea is a creeping vine that produces brightly colored (purple, magenta pink, etc) leaves, called bracts, with small flowers in the center. The branches are brittle but with care can be trained into semi-cascade or cascade designs, with a downward and spreading branch structure. Bougainvillea also prefers a kanuma-based soil blend.
Flowering Cherry
Flowering cherry trees make wonderful small and lush bonsai, especially when presented in a rounded, orchard tree shape. The flowers it produces in the springtime are beautiful. Flowering cherry trees don't tolerate cold as well as the other species I've mentioned above. They require frequent and thorough fertilization, as they consume resources voraciously during spring and summer and can easily and quickly weaken.
Picking out a potential bonsai
When choosing from nursery stock, some general guidelines apply. First and foremost, the trees you choose should be fairly healthy. It’s important to look for signs of disease, insects, or ill-health. Healthy specimens will be vibrant, pliable, and lush. Avoid trees with too many dead or discolored areas. Checking the foliage thoroughly is a good first step. Next, examine the area beneath the foliage. A healthy tree with a good trunk and surface roots will always yield the best bonsai. Be open to the natural elements of the tree when looking for bonsai material, and don't limit yourself to a single design idea or bonsai style. The more open your mind, the more possibilities will reveal themselves.
Do a little digging
When looking at the trunk line and surface roots, you may have to brush away fallen needles, dirt, or moss. While being mindful not to disturb things too much, try to find where the trunk ends and the roots begin. Often there is a lot of dirt around the trunk - too much, sometimes. Dirt mounded up around the roots can obscure a lot of things, like ugly bulges from grafting, or even more branches. Most people don’t examine their container trees or shrubs down to this detail - don’t be afraid to get your hands dirty in your quest for bonsai material!
Once you've found or nearly found the base of the tree, you can pick through the branches to determine approximately how many there are, what they look like, etc. Experienced bonsai hunters will already see potential designs or even the finished tree in their minds. Beginners should look for areas where too many branches have sprung from a single location. This can create bulges called whorls, which are hard to disguise in the long run, or even a “reverse taper”, where instead of gradually getting thinner toward to top of the tree, the trunk becomes thicker in an area. These qualities can be somewhat immutable, even for experienced practitioners. Your best bet is to look for trees that have none of the features described above, or at least as few of them as possible. If there are flaws on your nursery stock piece, it's best if they are toward the top of the tree because they can be removed completely during the bonsai-design phase, to shorten the tree and make the trunk appear larger in proportion to the foliage.
Turning cons into pros
Some potentially negative features are common with certain species and can be used to your advantage with some practice. For example, Boxwoods often have multiple “trunks” emanating from the base of the tree. It can be challenging to find a Boxwood with a single thick trunk, so be open to twin or triple trunks. Multiple trunks can lend themselves readily to a lovely and elegant bonsai design.
Some spruce have a second trunk partway up or near the base. If a tree presents this way, it can be made into a “mother-daughter” style tree, or even a bold, non-traditional design contrasting a live trunk with a bleached and carved deadwood trunk within the same composition. Mugo Pines tend to grow low with a lot of branches swirling around but no defined trunk-line to speak of. Stout Mugo trunks for informal upright bonsai can be found, and are still desirable, but a low and spreading Mugo growth can be easily trained into a dramatic cascade bonsai with time and patience.
Species care
All of these species, except Bougainvillea and Azalea, are cold-hardy and need a period of winter-dormancy to stay vigorous.
Keep in mind that Coniferous and Broadleaf Evergreen trees photosynthesize year-round. Conifers carry energy in their foliage because they use it all year, and as a consequence, they have relatively weak roots compared to deciduous trees. Deciduous trees lose their leaves in autumn and survive winter almost entirely off of sugars stored in their vascular system. For this reason, it's never a good idea to remove too much foliage at any one time from a conifer, to disturb the roots too much during potting, or to ever bare-root the tree. Conifers require the presence of microorganisms in the rootball, and without that, they'll quickly weaken and likely die.
Working through the seasons
One last, but all-important thing to consider at this time: What season is it? If it’s spring and you are buying nursery-stock trees, most can be worked on right away if it's early enough in the season. Pines shouldn’t be worked unless it’s late winter still. Others, like juniper, are best worked closer to summer but when it’s still cool. If it is summer, it’s best to wait out the hottest weather - resist the urge to do very much to your trees. Instead, use the time to study your trees, and think of all the possible designs you could pursue. Read and watch videos about bonsai. Come hang out at our garden. Just be patient, wait out the heat.
Early fall (late summer?), with cooler but still-humid nights, is a great time to work on Spruce, Juniper, and Mugo Pine. Recent horticultural science points toward fall being a great time for trees to settle into a new pot and/or recover from styling because fall vascular growth is second-only to spring vascular growth. The difference is, a tree is “energy-positive” after growing all spring and summer, while at the very end of winter, it is losing its cold tolerance and has used most of its energy stores, but hasn’t yet put forth new growth. Spring is still considered by most to be the only appropriate time to pot bonsai, but the discussion is ongoing, with modern bonsai practice leading the way to safe and effective early-autumn bonsai work, especially for certain species.
You're on your way to owning a bonsai collection
So, now you've found a tree that fits all or most of the criteria. You may have even found more than one. You simply can’t go wrong by getting more than one tree. If you can buy several decent specimens at the same time, of different species or growth-habit, you'll have more options for bonsai design, and perhaps the beginnings of an impressive collection of bonsai. I believe you will be more likely to stay on top of your bonsai care routine, too, if you have a small group of bonsai that you love to look at, as opposed to just one. The best part is, you will have begun the bonsai journey in an affordable, fun, challenging, and satisfying way.
“If God wants me to have three bonsai, then twenty-five bonsai it is.” - Unknown