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Author Topic: Poncirus winter protection  (Read 142 times)

Vlad

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Poncirus winter protection
« on: September 04, 2020, 11:08:20 PM »
I am in zone 6a. I have a Poncirus trifoilata that I planted in ground this spring. It is about 3 feet tall. Do I need to provide winter protection? If so, would I need to include a heater?

Florian

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Re: Poncirus winter protection
« Reply #1 on: September 05, 2020, 04:14:44 AM »
Poncirus is reputed to withstand -20 to -25C, depending on the source. I have not been able to test this but there are other people here who have seen those kind of temperatures. I would think that light protection during the first few years should suffice and no heating is necessary but others may know more.


kumin

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Re: Poncirus winter protection
« Reply #2 on: September 05, 2020, 07:17:05 AM »
There's a range of hardiness that involves variation between plants, duration of cold exposure, and severity of cold exposure, as well as age of plants and the type of microclimates.
There's likely, however a lower temperature limit that Poncirus will succumb to. -31C is considered fatal to any branches exposed for several hours. I've seen young trees killed down to the level of protective snow, any growth below that point survived.
At -25C late season growth is damaged or killed from the top down, often leaving the lower sections of branches alive.
So, essentially, the damage is incremental, starting at perhaps -15C on tender, late season growth, then increasing in severity until -30C, at which point freeze damage is near total, with the possible exception of large diameter trunks on old trees.
Desiccating winds during winter are also damaging, especially during periods of bright sun and frozen soil. The cambium must remain in a "dry" state to prevent destruction by freeze damage. Succulent bark is very vulnerable to cambium destruction and splitting and subsequent sloughing off of the bark. This creates a bit of a quandary, the inner bark must remain tight and dry while slowly desiccating during winter. Susceptible branches are a bit of a battlefront as rejuvenating springtime forces begin reinvigorating up from the roots. It's very common to see a point in upright branches where the dying top portion meets the surviving lower portion. The more severe the winter - the lower on the uprights this transition will be.

Damage at -25C.




« Last Edit: September 06, 2020, 07:38:58 AM by kumin »

Ilya11

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Re: Poncirus winter protection
« Reply #3 on: September 06, 2020, 08:54:34 AM »
I am in zone 6a. I have a Poncirus trifoilata that I planted in ground this spring. It is about 3 feet tall. Do I need to provide winter protection? If so, would I need to include a heater?
I guess  6a is at the limit of a long time survival of poncirus.
Since you have a long period of frozen ground, avoid winter sun, put some mulch around the stem.
Ideally,a passive heat protection like a box of styrofoam will help, I do not think that you need active heating.
Best regards,
                       Ilya

 

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