winter Archives ⋆ Page 2 of 2 ⋆ Cold-hardy.com

Freeze damage

December 13, 2014 tarzan Comments 2 comments

My plan was, to closely monitor weather data and try to spot emergence of cold induced damage on different (more or less) cold hardy bamboos. With gathered data, I’ll be able to determine cold hardiness of each individual bamboo, and detect possible ‘top kill’ conditions or (I sure hope not) conditions where bamboo completely dies. Bamboos are placed in different locations and can have their own micro-climate, but conditions are nearly identical. Small Chimonocalamus pallens seedling is planted under quite large Fargesia murielae, so it’s a bit more protected, but also much more tender because of it’s youth and extremely small size. Actually I will not be able to determine proper values for Chimonocalamus seedling, I will, however, be able to check its hardiness in it’s young seedling stage.

Chimonocalamus pallens - the first bamboo that had shown leaf damage. — Chimonocalamus pallens – the first bamboo that had shown leaf damage.

I will closely monitor temperatures and try to write down absolute low temperature (usually morning) and highest temperature. I will add wind conditions information, soil freeze / thaw conditions, information about snow cover accumulation, exposure to full sun, fog, rain, freezing rain… While closely checking weather conditions, I’ll also keep my eyes on all the plants, trying to notice any sign of stress or damage. When weather conditions won’t allow me to identify damage, for example in prolonged period of time with temperatures below freezing or rainy weather that will temporarily re-hydrate damaged leaves, making them look alive, I’ll try to determine the cause and extent of damage when it becomes evident.
I’ll keep all my recordings for further analysis and in try to create easily readable table or chart. Non-threatening days (with temperature above freezing) will be excluded, but will be mentioned as annotation in case of possible impact on plant’s condition later on when freeze damage occurs.

First freeze damage victims: Chimonocalamus pallens and Borinda fungosa seedlings

When temperature dropped and freeze the soil enough (-5°C/+2°C), Chimonocalamus pallens was the first of bamboos that started to show signs of leaf damage. Damage most likely started because of frozen soil and direct sun exposure. Leaves were exposed to full sun and roots were mostly shaded by F. murielae. With day temperature just above freezing, without wind and fully shaded, 1 cm of soil remained frozen. That was enough to damage the leaf cells. Leaves ended up slightly damaged and some of the youngest branches dried out during the first cold spell.
At the same time, the last shoots of Borinda fungosa also started showing some damage. The unbranched shoot is missing the top leaves, but culm still seems to be alive. Spring will tell if branches or buds got damaged. Autumn shoots that branched out recently had shown some damage and had lost a couple of fresh branches, but at least some of them might still be alive. Full extent of damage will also be visible in the spring.

DATA

Bamboo Name
Phyllostachys aureosulcata ‘Spectabilis’
Phyllostachys pubescens ‘Moso’ (3 year old seedling)
Phyllostachys aurea
Borinda (Fargesia) Fungosa (3 year old seedling)
Fargesia denudata ‘Lancaster 1’
Fargesia Murielae
Hibanobambusa tranquillans ‘Shiroshima’
Pseudosasa japonica ‘Tsutsumiana’
Chimonocalamus pallens (1 year old seedling)

Second cold wave.

Just after Christmas, we’ve received another wave of cold air that persisted longer and temperatures dipped much lower. Luckily we’ve received around 20 cm of snow in the beginning when temperatures started plunging. I used that snow cover to tarp down and bury Borinda fungosa which is not hardy enough to survive during harsh winter conditions. Most of the time it was sunny weather with moderate to strong wind. Moso leaves that were not protected by snow started to show signs of freeze damage when temperature dropped to -13°C. When temperature dropped to -15°C, first signs of damage appeared on Hibanobambusa tranquillans ‘Shiroshima’, exposed branches of Phyllostachys pubescens ‘Moso’ seedling got completely fried, Borinda was already tarped and covered with snow to prevent cold air from entering the space between tarp and the ground. Temperatures remained below freezing, but sun managed to melt the snow on south facing positions which caused quite some damage on bamboos that got exposed that way.

Phyllostachys pubescens ‘Moso’ got completely defoliated (perhaps even top-killed) on it’s southern side. Snow cover remained on it’s north facing side, which kept all the leaves and had shown only minor signs of any kind of damage. On January 3rd, snow started melting and temperatures started to rise. When daily highs were above freezing, there was no additional damage on any of bamboos. At the end of the cold wave, southern wind brought warm weather and I untarped B. fungosa to see it’s condition. It was looking surprisingly good. While exposed parts of culms got completely killed, everything that was tarped remained in relatively good condition. Old culms and shoots from late spring/early summer received only up to 30% leaf damage, shoots from early autumn, on the other hand, got up to 90% damaged despite protection.

Result of second cold wave

Half bald Phyllostachys pubescens. Exposed southern side got fried, while snow cover on the other side protected it from severe cold

Chimonocalamus pallens (1 year old seedling) got devastated. Despite being covered with snow and branches of F. murielae, it got completely fried, dried, broken and dead. I still hope rhizomes remained alive so it can ressurect in the spring.

Phyllostachys pubescens ‘Moso’ was also seriously hit. It was covered in snow, but sun managed to expose it’s southern side. Southern side is completely fried, northern side almost undamaged.

Borinda fungosa lost from 20% (mature shoots from spring and last year’s growth) to 90% (youngest shoots) of leaves. It was tarped and bent almost to the ground, which proved to be sufficient protection. All the older shoots survived, late summer/early fall shoots seem to be damaged, but damage can’t be determined before spring. Some of the nodes might still be alive. Tarped and snow covered leaves were only slightly damaged, some started to turn yellow like those in the fall, those that are dead started to dry, most of surviving leaves are green.

Hibanobambusa tranquillans ‘Shiroshima’ had shown quite a lot of damage, but it seems it’s holding well. Snow covered leaves were undamaged, exposed leaves are severely damaged but still show signs of life. Several older culms that were too rigid to get any snow protection seem to be dead.
Phyllostachys aurea is holding well, much better than in 2012 when it got top killed. It does show some frost damage, but most of the culms took the cold surprisingly well. Even some of exposed leaves managed to recover, despite being totally dried out and wilted during the cold sunny weather.

Pseudosasa japonica ‘Tsutsumiana’ got only slightly damaged. Some of the leaves were exposed to cold and were damaged, but they are still alive. It does have several tops fried. They are also water-logged most of the time and they never lost supply of water.

Fargesia denudata ‘Lancaster 1’ is showing some damage as well. It got attacked by voles once again, so it might be vole issue, not the cold alone. I really need to do something about voles.

Fargesia murielae is almost undamaged. It got flattened by the snow, with only middle of the clump partly exposed. When snow melted and some of the branches experienced the cold, it didn’t do much damage to them.

Phyllostachys aureosulcata ‘Spectabilis’ was also almost flattedned despite it’s larger size. I shook it a bit to keep the snow off, so it was exposed to the cold and the sun. It had shown minor signs of damage on youngest shoots during the worst cold, but it recovered. Late autumn shoots that were just starting to branch out in late fall, might be damaged, but are still standing.

What do you think of this post?

Useful (2)
Interesting (1)
Awesome (0)
Boring (0)
Sucks (0)

Cold

December 5, 2013 tarzan Comments 14 comments

Cold weather ends the growing season sooner or later, this year it was rather soon. With no snow insulation, cold can induce more damage that with thick layer of snow insulation. This year, despite all the cold, we are yet to see the first snow.

Hard frosts had made Borinda fungosa suffer. — Hard frosts had made *Borinda fungosa* suffer.

Borinda fungosa seedling was holding on very well down to -5°C. Soon night temperature dropped down to -7°C and many of the leaves got damaged. Leaves that remained undamaged, surprisingly remained unfolded even during sunny and windy weather. It did loose all the shoots from this autumn, as it did last winter, but this time, some of them remained tall, only loosing their fragile top. Perhaps in the spring, they will begin the branching process. Cold weather persisted for around two weeks, daily highs were slightly above or below freezing, it was sunny and windy most of the time. Morning low temperatures were between -5°C and -8°C. This is it’s second winter outside, I’ll see how it resists cold. Last year when it was covered in thick layer of snow most of the winter, it managed to keep most of the leaves intact.
Well, the problem with all that snow insulation was weight. Heavy wet snow broke all the taller culms and only a couple of old tiny ones remained. Dead shoots that grew in late fall were not all dead, one of them managed to grow branches around the lowest node, that was buried under thick layer of mulch.
After almost a month of very cold weather, with fog persisting through most of the day, with day temperature slightly below freezing, leafs managed to unfold, showing the damage. It looks like most, if not all, leaves were completely killed or badly damaged. Culms and branches are showing their dark brown color and they seem to be alive even after prolonged period of cold weather. Hopefully in 4 months we’ll get some warm weather for it to recover.

Shiroshima with it's beautiful varieagated leaves remains almost intact. — Shiroshima with it’s beautiful varieagated leaves remains almost intact.

Hibanobambusa tranquilans ‘Shiroshima’ is looking hardy enough to survive this kind of cold dry weather without hassle. There’s no evident damage, not even on several late fall whip shoots. Whips stopped growing with arrival of cold weather, lower nodes actually hardened enough to drop off culm sheathes, while their tops remained fresh and stopped growing completely. I guess we’ll have to wait and see if they resume in the spring. With temperatures close to freezing, white variegation on the leaves turned into bright yellow color, making bamboo look even better.

Moso seedling that remained inside the pot is showing quite some damage.

Phyllostachys pubescens ‘Moso’ seedling that escaped it’s pot is showing moderate leaf damage. It’s evident, that there’s almost no damage on the escaped part of bamboo that ran out of the pot two seasons ago. Leaves that were pale during the summer and showed some kind of stress, wilted after first heavy frost. Dark green leaves mostly remained undamaged, but they do tend to wilt when exposed

Moso seedling shows some damage, but it looks quite good.

to sun. Wilting is normal, because soil already got frozen on top and bamboo have to save water inside it’s leaves.
The part that escaped managed to put out numerous runners and a couple of shoots that barely poked out through the mulch. They are most likely whip shoots that missed their growing season. So far they haven’t got soft and are most likely alive, waiting to resume in the spring. Last year, pot ended up as home of mice family that stayed there throughout the winter. They didn’t do much damage, but there were holes all around the pot and I’m sure there was some root damage. Well, better mice than voles! They can devastate whole bamboo clumps.

Umbrella palm seedlings, planted around the garden and inside the pond didn’t take the cold well. First hard frost killed everything above the soil/water level, and most likely, rhizomes as well. We’ll see if it restarts in the spring, if not, I still have one large seedling kept safely inside.
At first dark green damaged leaves turned into straw color. They’ve kept their appearance as they would still be alive. Dry clumps of umbrella papyrus are looking quite good. I’m going to keep them for a while, if rain or snow doesn’t make them look ugly that is.