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Bonsai master Hal Sasaki. Photo by Theo Stroomer

How to Train Your Bonsai Tree

Growing a bonsai isn’t as hard as you think, says this Denver bonsai master.

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Harold Sasaki wants to dispel some myths about bonsai: that they’re hard to grow, for example. “Most often, a bonsai dies because of lack of light,” he says. “So maybe you just put it in the wrong place.” Sasaki, who is 82 and goes by Hal, hears many such stories of failure; he has a number of his own, especially from when he started as a teenager in Hawaii. One of Denver’s most prominent bonsai masters, he’s co-taught beginner bonsai classes ($105) at the Denver Botanic Gardens for over 40 years, and also teaches and sells trees at his own business, Colorado Bonsai ($150, a smaller class size). His main goal: to make bonsai approachable, not intimidating.

Bonsai (say: bone-sai) is the ancient Japanese art of growing tiny trees in pots; the term bonsai literally means planted in a container. Contrary to popular belief, bonsai aren’t genetically dwarfed varieties; they’re the same species as their full-size brethren. Bonsai enthusiasts train, or shape, trees—using techniques like careful pruning, or wiring branches to grow a certain way—to assume the form of a full-size tree in miniature. The results can be stunning, with patient work. But they’re surprisingly resilient plants, if you give them a fighting chance (one ficus bonsai in Italy is over 1,000 years old). The key, says Sasaki, is to treat them as what they are: trees, not ornaments.

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“One of the big misconceptions about bonsai is that they grow different than in their natural, big-leaf form,” says Sasaki. “So people put them on a coffee table, because it looks best there. They treat the plant like it’s made out of silk, and forget that it’s alive and growing, and needs a certain amount of light. You have to grow things where they need to grow.”

(Read more about Harold “Hal” Sasaki.)

Ideally, that means a protected-but-sunny spot outside, at least in warmer weather (in Colorado, bonsai can’t be left out in pots in winter). But Sasaki knows that growing bonsai outside is impractical or impossible for many people, especially apartment and condo dwellers. So for his hands-on classes—students go home with a tree—he tries to select species that are more suited to growing indoors year-round.

The smaller the leaf size, Sasaki says, the more light a bonsai needs. That ironically rules out a lot of native pine and juniper species for most indoor settings. Sasaki’s go-to bonsai for beginners in Colorado? Portulacaria afra, aka Dwarf Jade, a succulent with thick, dime-sized leaves. “I use it so that students will have a higher chance of success,” he says. Dwarf Jade, which is from South Africa, also tolerates the constant warm temperatures of indoor growing better than native conifers, which like colder nights. Those long-lived ficus are another good pick for indoors.

Sasaki says he tries to give as much horticultural background and care tips as possible in his classes, so that students not only understand what to do, but why. To water, Sasaki fills a bin large enough for the whole pot, and then submerges the plant past the pot rim and leaves it until the air bubbles stop. That, he says, thoroughly wets the root zone, and he doesn’t water again until the plant is almost dry.

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Above all, if something’s not working, he says, change it. Move the plant to a different location with more light. Or water less, not more. “People often say their tree died because they overwatered it,” he says. “And I tell them, ‘If you think you overwatered it, then why did you keep doing it’?”

What’s kept Sasaki teaching for four decades? “I want other people to enjoy what I have all these years,” he says. “I try to make it as bulletproof as I possibly can for them, and to demystify it. I want to tell people what joy you can get out of these plants. The rewards are there to gladden your heart.”

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