Boxwood Winter question

tj241

Hello - Newbie here!

I live in Southern NJ and I have a nice boxwood bonsai that I keep outdoors but am now concerned about the winter. Everything I have read states that it is ok to keep the boxwood outdoors during the winter as long as it is protected / sheltered from wind and frost. BUT I have also read that boxwood are hardy to only around -4 celcius.

What to do when temp drops below -4 celcius? Garage (no light) or indoors (with light)

Any help / advice is appreciated!

-T

Advertisement

Mcspeed

You don't want to bring it inside to a warm house, this will have it try to break dormancy, not in a day, but not the best way to approach winter, especiall if you forget or it's real cold for a stretch then you have an indoor tree.

I translate -4c to be about 25 f, up here most I know have the boxwoods in a cold frame, although cultivar may dictate hardiness.

__________________
If at first you don't succeed -- skydiving is not for you.


Always remember that you're unique -- just like everyone else

Enjoy this day.
Bill

tj241

I actually have a vacant apartment above my garage. It's unheated. Would this be a good option?

Thanks

Dav4

I've never kept boxwoods as bonsai, so take this for what its worth. Boxwoods are hardy broadleaf evergreens which are commonly planted as landscape trees in regions where the temps routinely fall to 0F or lower. Unless you have a less hardy variety, as Mcspeed mentioned, your tree should be able to tolerate temps much lower then -4c provided some winter protection is offered. Broadleaf evergreens are very suseptible to dessication from the winter wind and sun. Up here in zone 6 MA, lots of folks just finished wrapping their landscape boxwoods and hollies with burlap to prevent foliage winter burn...keeping your tree in a protected area out of the wind and sun does the same thing. Mulching the pot will also protect the roots from extreme winter cold, as well. Hope this helps,


Dave

Edit- I just read your last reply. That situation may work, with some caveats. Generally, the goal with overwintering trees is to keep them dormant until springtime. Dormancy requires temps that don't exceed 40F consistently. You're going to have to watch the temps closely to make sure it doesn't get too warm, which would allow the tree to break dormancy and start to grow, and I doubt there is enough light there to allow for normal growth. You will have to closely monitor you tree for watering needs, as well.

I've learned that the most effective overwintering scheme is usually the most simple one. I'm a big fan of putting my trees away for the winter and essentially forgetting about them until spring. Placing your tree in a protected area outside and mulching the pot will allow you to do this, more or less.

Dave

rockm

I have overwintered boxwoods (buxus microphylla, the "Korean boxwood" cultivar, as well as American and English boxwood -- (Buxus sempervirens "Arbvorescens" and Buxus sempervirens "suffruticosa") here in Va. (zone 7) outdoors with only a 6-7 inch mulch on the roots and a wind break for the last 10 years. They haven't had a problem. The foliage can bronze a bit in really cold weather, like 10 F and below, but it greens up come spring.

The issue is what kind of boxwood you have. Boxwood cultivars sold as landscape material in your area are entirely winter hardy. If you purchased the boxwood you have from a mallsai vendor there is a chance it could be Buxus harlandii, which isn't very winter hardy.

If you bought the plant from a local landscape nursery, it should be fine. I would not put any boxwood in a dark garage for the winter. You're asking for trouble if you do that.

dtree

How much light does a dormant boxwood require ? I am in zone 4/5 and am referring to Kingsville boxwood. Sunlight ? Artificial light ?

Thanks

rockm

No plant does very well in artificial light. Boxwood does need some light in the winter to stay healthy, but that's not the major concern. Unless you can keep them constantly below 35 F or so, they will begin growing. Additionally, at warmer temperatures--starting around 40 degrees or so--insect activity can become a problem. Indoors, with low humidity and little air movement, spider mites can become a real concern with dense plants like boxwood.

dtree

I keep the plant at 28-35 degrees, with low light (north window). It is the best I can do, do you have any other suggestions ? Thanks again for your help.

rockm

I would keep the plant outside near a south facing wall on (or in) the ground with the pot mulched under seven or eight inches of pine bark, or right up to the first branch. I'd also surround the plant with a burlap barrier on all sides. I'd let snow cover the plant entirely -- if possible.

If you only have the option of keeping it indoors, I would not keep it on the windowsill. I tried to overwinter a boxwood inside on a southfacing windowsill for a winter. It died in a few months--. Someone who has successfully overwintered Kingsville inside may be able to provide better advice on how to do it successfully.