It’s here again.

That freezing, fluffy white stuff is all over the place. That four-letter word that seems to occur annually and stay for least a couple of days each winter. Now it’s ice. Why am I not in Hawaii?

It’s not really what I signed up for by moving here to this wonderful garden Mecca otherwise known as Seattle…

Fortunately, “my babies” just love it.

I’m talking about the wee miniature and dwarf conifers that I’ve been miniature gardening with for the last ten years – thankfully, they are hardier than me.

Much hardier.

Here is a quick snapshot of the different dwarf and miniature conifers that are ideal for the freezing/sub-freezing temperatures. This is only an overview of the hardiness of each species, as the hardiness of some of the varieties may vary. (A good example is the darling Mhondoro Hinoki that is hardy to -20F while the Jean Iseli Hinoki is hardy to -30F.)

Canada Hemlocks: -30F or Zone 4

Hinoki Cypress: -20F or Zone 5

Dwarf Alberta Spruce: -30F or Zone 4

Dwarf Cryptomerias: -10F or Zone 6

Mugo Pine: -40F or Zone 3

Dwarf Fir: -30F or Zone 5

Dwarf Norway Spruce: -40F or Zone 3

Japanese Holly: -20F or Zone 5

Some of them are pretty hardy / hardier than me / as you can see. ;o)

We’ve included the cold hardiness zones within each listing in our online store so you know exactly what you can plant with success for your area. For warmer regions, please consult this blog post to get to know what plants can tolerate the heat in your area.

Getting it Straight

To keep myself straight, I rely on the actual temperatures when discussing hardiness zones. I think it’s because I was raised in Toronto, Ontario, and often get the Canadian/American/Sunset Zones completely mixed up plus, I interact with a variety of gardeners throughout the world. So it gets a little embarrassing with a name like Two Green Thumbs when I get the zones wrong.

So, I stay with one way to gauge and discuss hardiness and, for me, that is Fahrenheit. I don’t have to remember to convert anything in my head, I don’t have look up anything and I can eliminate a lot of errors that way. More often than not, the plant’s tag will have the minimum winter temperature on it. It’s better to be accurate than conventional sometimes.

Choose Hardier Plants for Your Containers

Now keep in mind the rule if you are planting in containers. There is a 15 degree difference in the hardiness of the plant when it is planted in a container. When planted the ground, the earth insulates the roots of the plant. When you plant in a container, you adjust for the hardiness by adding 15 degrees to the lowest minimum temperature. Here’s an example: let’s say the Mugo Pines are hardy to -50F. If we plant one in a pot, that Mugo is now hardy to -35F because it doesn’t have Mother Earth around it, keeping it warm.

And, always remember that you can plant a container at anytime!

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