T here’s a topic that seems to crop up each spring as preparations get under way for the annual Bonsai Beginners class that CBS organizes. Shimpaku or some other variant of juniper has always been the material of choice, but the notion that maybe a Ficus should be offered as well will usually get floated by one of the teaching team. It’s a way to make sure that apartment dwellers, who have no access to the outdoors, would have a good reliable choice in a first bonsai plant. The motion gets made, and each year the vote has been against adoption. To keep things simple and stream lined, only one type of tree is offered.
The justification is that junipers can indeed be kept indoors. Mention is made of Jack Wikle, a pioneer of indoor bonsai raised under shop lights, who has keep a variety of trees, including junipers, indoors their entire lives with no whiff of outside air (or light). But is it really possible to keep a juniper indoors?
I have been amused to see how vehemently the topic can get worked over on a few of the Face bonsai discussion pages I look at from time to time. It works out like this: A newly minted bonsai hobbyist will post a pic of their very first tree, like a proud parent. Its most often standard issue landscape juniper in a nondescript pot, usually with a layer of glued on rocks AND a mudman AND a pagoda. They’ll ask what fertilizer to use and how they should train the treewhat about wire? And this is where the helpful souls pile on. They have 4 or maybe 5 trees, they’ve watched some YouTube videos and maybe even read all the books their library has about bonsai, so they know-that tree needs to go outside, right now! New bonsai hobbyists, especially those that make that first purchase as an impulse buy, seem invariably to think that the bonsai, being so small, is also delicate, and needs to be coddled and soothed and protected. So they find a windowsill to park it on, inside the home, where they can look upon its coolness and neatness anytime they want.
And the Sages of Facebook just won’t stand for, that tree needs to be outdoors. Why it must be out doors they can’t make clear. This is the downfall of parroting the accepted wisdom of others. They just know that juniper is on the ‘outdoor list’ so can’t be inside. But why?It’s certainly dryer (lower humidity) in most homes, but junipers, tough as boot leather, often thrive in dry environments. Light indoors can be low, but a south window is a good start, and technology, so beloved of modern Humans, can supplement low lumens. Temperature is the real hang up for junipers and similar plants indoors. At some point, they want to take a rest. Full dormancy to suit an elm or maple indoors is impossible, and they generally peter out after a year or so.
But how much rest does a juniper really need? CBS gets its juniper stock from Liner Source, a commercial grower in Eustis, Florida. Eustis is a bit north west of Orlando in Central Florida. For reference, that’s Hardiness zone 9A-usual low temperature about 15 degrees, average usual 30ish at the low end. It can and does get in the 80s in January in that area. So full on dormancy is not really happening. There is a school of thought that while deciduous trees do truly go dormant, conifers-the so called “ever-greens” do not. They slow way down, and may appear to be sleeping, but it’s a much lighter slumber than their deciduous brethren take. If light and temperature are conducive, they may photosynthesize a little-or a lot.
|The Sage of Ann Arbor, Jack Wikle.|
As mentioned before, Jack Wikle kept junipers indoors for many years. He is not the only one to do so. The Brooklyn Botanical Garden guide to indoor bonsai lists juniper as a “challenging, but possible” species for indoor culture, recommending a cool to cold situation during the winter. Id agree with that advice. But my feeling is that good drainage and proper watering are even more important. An indoor juniper must never ever dry out, but also can never have wet feet.
If it sounds challenging, it may be less hard work than you think. Visiting a financial professional at his office in a new building at Easton, I was surprised to see a juniper bonsai on the table behind his desk. It was a Father’s Day gift from his young kids. Some might say he’s doing everything wrong: a juniper indoors, in a north facing window, never fertilized and watered on a strict schedule. But how wrong can it be: the plant is alive. It could use a shot of iron and nitrogen, but it is alive, has new growth and is reasonably compact (not spindly). So if junipers indoors are a challenge, it is a challenge that can be taken on successfully!