Indoors or Outdoors?

First there is no such thing as an indoor tree! All trees are designed to live outdoors in the open in fresh air where they are exposed to the sun wind and rain. Having said that, modern homes can provide suitable conditions for some subtropical and tropical species. This is just as well, since people are increasingly living in cities where they have little or no outside space.

Indoors

Most house plants are subtropical in origin, so if you can keep those healthy then you should have no problem with subtropical bonsai.If you do keep subtropical bonsai, they will benefit tremendously from being introduced to the open air when the weather is warm enough.

There’s something about fresh air, natural filtered sunlight and gentle rain – the tree seems to know. The color will improve, the growth will become sturdier and it will look much happier in general appearance. If you don’t have a garden or balcony, even a windowsill will do, so long as the tree is not left in the blazing sun all day long, at least until it has acclimatized.

Tropical species may need a little more heat and especially humidity than you would find comfortable in your living room. The real tropical bonsai enthusiast will go to great expense to build a temperature and humidity controlled conservatory. Fortunately, there are few truly tropical species in commercial bonsai production.

Outdoors?

If you don’t want to clutter your home with bonsai, or if your a confirmed bonsai addict, your garden will soon be over-run by hardy bonsai. These will not tolerate indoor conditions at any time of the year. Hardy species can tolerate freezing of the soil in the pot for several days longer. Many of them absolutely must have a period of freezing in order for the to maintain their health – or even to survive.

They can be brought indoorsfor display for a few days, but must soon be returned to their natural habitat. If they are kept indoors for too long in summer their shoots will become very long and spindly, and will eventually collapse and die, if they are kept indoors for mare than a day or so in winter, their natural an necessary period of dormancy may be broken and all the primary buds lost. This can sometimes even be fatal!

The following rules of thumb are worth remembering.

• All conifers (pine, spruce, juniper, yew, cedar,larch, cypress) are fully hardy and cannot livc indoors.
• All broadleaved deciduous species (maple, beech, hornbeam, apple, apricot, cherry,) are fully hardy and cannot live indoors.
• Elms and zelkovas are often wrongly named in order to circumvent the important regulations. If you’re in any doubts about their identity, then if they’re japanese, they’re fully hardy, but if they’re not then then they’re more than likely sub-tropical.
• If you’re in really serious doubt, buy your bonsai in winter. If it’s on display in full growth in a green house, you can be certain it’s tropical or sub-tropical species. If it’s displayed outside it’s hardy – or dead! To check, scratch the bark with your fingernail, discreetly, on the underside of as branch. If you see green (cambium) it’s alive.