Anyone knows the hardiness of these perennials?

I am growing these perennials in Iceland, which is zone 6.
Anyone knows the hardiness of these perennials?

- Chilean mesquite
- Honey locust
- Crambe
- Asparagus
- Sea buckthorn / Seaberry
- Greater Galangal
- Acorus Calamus
- Ginger (the common supermarket ginger)
- Curcuma / Turmeric
- Bamboo, Phyllostachys edulis
- Good King Henry
- Amelanchier canadensis

I have grown all these plants from seed this year
So they are only small seedlings. Up 2-3 inch tall.

I have some seedlings indoors and some planted outdoors. For the aproaching winter, I can either let them indoors (but days will be very short and I am afraid they would die) or I can let them outdoors, or try both. Anyways, if they don't survive this winter, I hope to establish them next year, as they will be bigger. Here even broccoli and lavender can survive the winter, if provided mulching.

I am particularly curious whether I can establish the ginger, turmeric and galangal, the bamboo and the chilean mesquite.

Anyone has any experience with the winter hardiness of the above species?

Paulo Bessa wrote:
I am particularly curious whether I can establish the ginger, turmeric and galangal, the bamboo and the chilean mesquite.

Of those, the bamboo is the only one that might make it. Ginger, turmeric and galangal are all tropical plants that you will definitely have to bring inside or treat as an annual. I've only heard of chilean mesquite growing in zone 8 or hotter. The honey locust, asparagus, seaberry, GKH and serviceberry will do fine in zone 6.

I tested some of these plants last winter and spring:

- Chilean mesquite. Seems it could overwinter if seedlings are big enough and woody. But it seems to dislike the cold weather. Officially it is hardy to zone 8, but i could stand more I think.
- Honey locust. A 1 year tree overwinter outdoors without problem, but growth is poor in summertime. Seems to be cold hardy enough for zone 6 and even colder regions. But likes warm weather when it is growing.
- Crambe. Seems quite cold hardy. So far survived -8ºC without problem, but with mulch. I will see how it does with its first winter.
- Asparagus. Last winter, I fail to overwinter a 1 year seedling. I am trying again with much more mulch.
- Sea buckthorn / Seaberry. It is very cold hardy. Stands much colder than zone 6.
- Ginger (the common supermarket ginger). It survived outdoors -8ºC and freezing of the soil (even without mulch), when top part was already dead. Parts of the root suffered but other parts remain alive. This seems to show ginger is hardy at least to zone 8 and possibly zone 7 with protection.
- Curcuma / Turmeric. Same as above.
- Bamboo, Phyllostachys edulis. Seems cold hardy but a small seedling died through last winter. Cold hardiness depends on its size, and could go to zone 6 but not much more I guess.
- Good King Henry. Seems quite cold hardy. It will overwinter its first winter. So far seems to stand zone 8 freezing without many problems, but top part dies. Probably mulching helps.
- Amelanchier canadensis. Survived our zone 6 winter without protection. A small 10cm seedling. No problem. Should be cold hardy in much colder regions.

And I have tested a few more perennials...

- Pigeon peas. They took a minor brief frost, -2ºC, in a sheltered spot, and suffering just a bit. Colder than that and they readily die. So, they are cold hardy to zone 10, and in the limits of possibly zone 9, with protection, but it might depend on how long the chilly weather remains.
- Goji berry. Seems to stand zone 7 freezing when the plant is dormant.
- Moringa. Same as pigeon pea, but I have tested for colder than -2ºC. Because it is a more woody plant it could survive slightly colder frosts.
- Groundnut, apios americana. Survives zone 7 freezing, but colder than that can damage the tubers and make them die, if there is no mulching. I will see how they survive their first winter fully outdoors. The foliage is just like a bean, it will not stand even chilly weather, above zero.
- Tiger nuts: below zero makes foliage die, but tubers survive when freezing is not hard. I have a plant outdoors and I will check if its tubers have survived the current zone 8 freezing weather.
- Oca: foliage readily dies with frosts colder than -2ºC. And if this happens before tuber formation, then your plant will just disappear into nothing. But foliage stands well frosts just around -1ºC.
- Avocado. A few of my seedlings have survived outdoors lows around -8ºC and freezing of the soil. I did not expect avocado to be so cold hardy.
- Pomegranates. They have survived even more severe zone7 like freezing, when dormant. A quite hardy tree.

The Honey Locust is rated as hardy to Zone 4.
I know of a guy in Sask, CA who claimed half of his died after several days of -40* (@ -40, C=F).

The Chinese Goji is hardy to zone 5

Asparagus does fine in the northern US, and most of Canada. So, about zone 3-4 might be its limit.

I agree that ginger & tumeric are tropical plants, so you're on your own there.

I didn't see your species of bamboo listed, but here is a link to a Canadian company that has many cold hardy bamboo offerings.
http://www.bamboogarden.com/cold%20hardy%20bamboo.html
Might give you some insight for future plantings.

Hi. I've read a reliable account that Avocado can survive frosts of -9 degrees Celsius in some valleys in Australia - even producing fruit. They are very cold hardy as long as they are not subjected to strong cold winds. In more temperate areas they sometimes lose some or all of their leaves over winter, but they quickly bounce back once Spring arrives. Happy experimenting. Chris

Paulo Bessa wrote:
- Oca: foliage readily dies with frosts colder than -2ºC. And if this happens before tuber formation, then your plant will just disappear into nothing. But foliage stands well frosts just around -1ºC.

There is some difference between varieties as well. The varieties Hopin, Sunset, and Real Seeds Red are pretty resistant to frost. Mexican Red, Pink, Crema de Rosa, and some other less common varieties are more vulnerable. Mexican Red suffers some leaf damage with even the lightest grass frosts. So, if you don't know which varieties you have, best to be cautious.