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Protect your Semi-Hardy

As winter is soon to be here, it is time for the semi-hardy trees to go into protection. This usually is around the end of October.  Read helpful hints on how serval senior members protect their semi-hardy trees.

Some of the trees that are semi-hardy and cannot withstand a Chicago winter are:

  • Japanese Ume
  • Satsuki Azalea
  • Chinese Elm
  • Cedar Elm
  • Pomegranate
  • Coast Redwood
  • Harland Boxwood
  • Kingsville Boxwood
  • Olive
  • Trident Maple

The club recommends that for these trees you:

  • Keep these trees stored in a cold house, garage, or other protected area
  • Store them in an area that does not get colder than 20 degrees F
  • Water them every week or as needed
  • Some trees need some light, such as Satsuki Azalea. For these trees, keep a grow light on above them about 8 hours a day, or near a garage window
    • Azaleas will die below 23 degrees on their roots. They do best if kept from freezing. Azaleas also need light all year long
  • Dwarf pomegranates should not be allowed to freeze, that can kill them. Full size pomegranates will tolerate a frost

While most Hinoki Cypress (Dwarf) species need to experience winter cold temps, some species of Hinoki Cypress need a considerable amount of light during winter.

 Badar Zulgarni

 

There really are too many to name. It is best to consult a book or website to discover the hardy zone for each plant.  Chicago is zone 5 but err on the side of caution because the zone refers to plantings in the ground not pots.

And if it’s any help I pretty much treat mine like all my small bonsai they go under my back porch where they’re protected from freezing. So if you’re going to do Bonsai and you’re going to do subtropical if you need to have a place where you can protect your trees from freezing. Ask what zone a tree is when you purchase it. Those are the kind of things I take under advisement when I’m getting something newer trying to figure out where to put something away.

Phil Malhiot 

 

I have trouble with critiquing what others say about care. they usually are speaking from their experience.  We put the Hinoki in a couple of places; in the ground huddled with other trees or in the ground in the big hoop house huddled with other trees. the hoop house is covered with a trap and a little heat ( can drop into the low teens). This has worked for over 20 years. Jap. Black pines need the hoop house or a foot of mulch.Chinese Elms are growing in the ground in our back yard. We now put most of the potted ones in the garage without any light. Some are out in the big hoop house. In the past we just put On really cold nights we put a little heater in there. This has worked for 15 years.The azaleas go into the garage along with the Ume after they have experience some cold outside (ours currently are in a heated small hoop house where the temperature has been in the mid to high 30’s. In late winter they will go into the green house to wake up.
watering is done as needed. about once a week to a week and a half in the garage, monthly or so in the hoop houses.  Those outside in the ground may get watered once during the winter depending on the snow that they get.
I do not know if this helps or adds to the confusion.

Jim Beck 

 

I winter my Chinese elms, azalea, coast redwoods, and cedar elm in a cold frame outdoors.  It is a 2 foot deep pit that is lined with 3/4 inch plywood and braced.  It has a plywood cover so these trees receive no light except when I open the frame.  I open it when outdoor temperatures are above 40 degrees.  This allows excess moisture to escape.  Most of my small accent plants are also in the frame as some are only semi-hardy.  Watering is only needed if they get rather dry.  Often I just toss snow over them and it will slowly melt in.  These trees go into the frame when temperatures at night are consistently around 30 degrees.My olive, pomegranate, Harland boxwood, blue Atlas cedar winter in my minimally heated basement under LED (previously fluorescent) lights.  The lights run for 14 hours per day.  These trees do need to be checked often and watered as needed.  Watering is about once per week.  I let them get a little drier than they would get outdoors before watering.  I bring these trees indoors when temperatures at night are around 40 degrees.Just a note.  Siberian elms are often misidentified as Chinese elms.  They are entirely different species.  Siberian elms (Ulmus pumila) are winter hardy here and are often found growing wild aka volunteer seedlings.  Chinese elm (Ulmus parvifolia) are not winter hardy here and are not found growing wild in our region.  They differ in leaf size, leaf shape, leaf color, bark color and bark character, and longevity, as well as winter hardiness.
Hope this will be helpful.

Dan Kosta 

 

All my semi-hardy trees are still outside. At night or when cold wind is blowing hard they go on the ground huddled together under their platforms. I had a mouse problem last year and almost lost my maples. Those darn critters ate a lot of the bark off of them. So this year the trees are staying outside for a couple light frosts to get the mice bedded down in another place other that my trees. On the ground when temps are in low 30s if a frost is expected I also cover them with newspaper. It always worked with my beans so hopefully it will work with my trees. 

After temps stay consistently low they will go under my enclosed porch. It is not heated and dark. I water about once a week to a week and a half. Other than the mice last year they all have made it fine for at least 5 winters that way.

Charlotte Field