Colorado Overwintering

[nosckaj123]

Hello!

I am currently living in northern Colorado along the front range. Winters are generally in the 30s and 40s during the day but we can suddenly get very deep negative digit freezes that last for days. This past spring I purchased a Mugo pine and a Chinese Elm bonsai that have been growing well outside all summer. My concern is what to do with them over the winter.

Given the constraints of my living situation, my three options are:
1. Leave them outside with styrofoam insulation around their pots (leaving the tree exposed above) not sure how cold they could survive like this.
2. Place them in my unheated windowless garage. My concern here is the lack of light, could buy an artificial grow light. How much light would a tree need while it's in dormancy?
3. Bring them inside and restrict the amount of light they get by placing next to a shady window. Not sure this would induce sufficient dormancy due to the higher temperatures inside.

Ideally I'd have a window in the garage but since I rent, I can't make renovations. I am leaning toward that option with LED grow lights though. I appreciate anyone's thoughts in this matter!

 

[Carol 83]

Welcome to the forum! If you put your location in your profile you will get the best advice for your location. There are quite a few members from Colorado here who should be able to help @Colorado @ShadyStump .

 

[Colorado]

Welcome!

What I do here in Golden, CO is leave my trees outside as much as possible over the winter. Then I will bring some trees into the unheated garage for the “arctic blasts” that seem to come once or twice every winter when we get the -10F, etc.

So, for some trees that means that I bring them in quite a bit over the winter, such as a shohin itoigawa juniper, which I wouldn’t want to get below about 28F. Other trees, such as a large ponderosa pine, stay outside all winter with no worries whatsoever.

For your two trees - a Chinese elm and a mugo pine - I think the Chinese elm would need to go into the garage for most of the winter and the mugo probably the same, although maybe it would be okay outside in a shady location. For the trees that I leave outside, I shovel snow around their pots each time it snows. This provides both moisture and insulation to the roots.

Now I will just add an unsolicited 2 cents….I’ve found it much more enjoyable to do bonsai with native species here on the Colorado Front Range. The climate is simply too extreme and unforgiving for most species that are traditionally used for bonsai. However, native species thrive here as bonsai. Ponderosa pine, Colorado blue spruce, Rocky Mountain juniper, aspens, alders….there are countless native species that thrive here as bonsai and make it much more enjoyable in my humble opinion.

Have fun and good luck!