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Freeze Damage

Posted: Wed Jan 25, 2017 4:35 am
by Drew_from_ATX
It's been a sad month for my Gracilis bamboo due a very abnormal cold spell in Austin last month. ~90% of all the leaves have turned brown and dry :cry:

Any idea how long it will take them to bounce back and provide the much wanted screen? I'm also assuming the upsizing this year is probably gone as well. Any truth to this? See below..

Re: Freeze Damage

Posted: Wed Jan 25, 2017 7:29 am
by Glen
The answer to your questions depends on the extent of the damage. I would need to see more detail in order to make a better diagnosis.

If only the leaves are damaged, the plants will leaf back out from dormant buds just below the current leaf fans. In this case, the plants will look good in a few months, and they will size up pretty normally.

If the twigs are killed, the plants will need to grow from dormant buds further back on the branches or culms. The more progressive the damage, the longer the plants will take to look good.

If the plants are mostly topkilled, they will produce what are often called "survival shoots". If this happens, the plants will look floppy and messy for a while, but you need to let these shoots grow, as the plants will rely on them to sustain future growth. These floppy shoots can be tied up to make them manageable. Topkill would mean that the plants will not provide much of a screen until next year.

I also received damage to many bamboo plants. Most of my plants are currently producing new growth from dormant buds, revealing the exact extent of the damage. If yours are not currently doing so, they should within a few weeks. Watch them closely.

Do you know exactly how cold it was where you live?

Re: Freeze Damage

Posted: Wed Jan 25, 2017 9:33 pm
by Drew_from_ATX
Most of the twigs appear to still be green. The temps dropped down to 24, 19, and 18 three days consecutively. Another weird thing is that 3 of the clumps are starting to shoot which seems very early.. I didn't apply any fertilizer or anything. The only thing I can think of is that we received a ton of rain last week or they are rescue shoots..

Re: Freeze Damage

Posted: Thu Jan 26, 2017 12:25 am
by Cooper12
The culms look green I'd imagine they will releaf and produce similar size culms or possibly larger. We have not dropped to the teens here but have had 3 days with lows of 24 and numerous days of 26 to 29 . I'll look at mine once they pop out of the snow hopefully in a day or two

Re: Freeze Damage

Posted: Thu Jan 26, 2017 1:54 am
by needmore
My personal observation has consistently been that with total leaf burn even if there is releafing, the new culms are downsized. That seems to go against what others experience but that is what I've seen.

Re: Freeze Damage

Posted: Thu Jan 26, 2017 8:50 am
by Tarzanus
On fast growing smaller groves, I've seen usually slight upsize even when the bamboos got defoliated. I did not prune rhizomes at that point. The problem with winter damaged culms is - most will look rather crappy the following season, even if they re-leaf. For me, the damaged culms ended up with wilted, damaged small leaves, pale green and sickly looking. I have had much better results if I removed the damaged culms when new shoots reached maximal height in the early summer. I have had same poor growth on Moso and Phyllostachys aurea, Borinda on the other hand regenerates much better. It is, however, a bit more prone to have smaller shoots in the spring (or in my case of establishing seedling, same size with no upsize).

I will remove EVERYTHING from Hibanobambusa tranquilans 'Shiroshima' that will be damaged. That's one of bamboos that looks really bad for me when it regrows. Some branches die, new leaves are small and culms look like pom-poms. New growth is beautiful again. Cut, cut, cut.
I am not going to start about Pseudosasa japonica. That one also tend to look crappy after hard winter. Cut, cut, cut.

Re: Freeze Damage

Posted: Fri Jan 27, 2017 6:10 am
by Glen
Drew_from_ATX wrote:Most of the twigs appear to still be green. The temps dropped down to 24, 19, and 18 three days consecutively. Another weird thing is that 3 of the clumps are starting to shoot which seems very early.. I didn't apply any fertilizer or anything. The only thing I can think of is that we received a ton of rain last week or they are rescue shoots..
Those temperatures can do some real damage, especially to new plants. It is possible that the shoots you are seeing are a response to freeze damage, but new plants do sometimes shoot at odd times. You will just need to watch the buds and see what happens.

As an aside, for gardeners in southern U.S. zone 8b...
I learned years ago that the ONLY clumping bamboo that is truly bulletproof during cold winters is Bambusa multiplex. I have never seen it hurt very much in 17 years. Over this time period, I have seen Bambusa textilis severely damaged several times. If I were in zone 8b, and I needed a privacy screen, I would plant 'Alphonse Karr', as it is the most upright clone on Bambusa multiplex. Bambusa textilis var. gracilis is a better screening plant because it is more upright and taller, but defoliation from cold is a real disappointment for someone relying on a screen for privacy. As a practical matter, cleanup of a mature topkilled bamboo screen will be a real mess.

I believe that many of the accounts of long term success with Bambusa textilis in zone 8b are based on observations of plants grown within urban heat islands or other protected microclimates. When I lived in a rural 8b, I was unhappy with the frequent damage that I saw on Bambusa textilis. It was a great plant during stretches of mild winters, but it was certainly damaged too often to encourage me to grow it as a critical landscape element.

In zone 9a, I have not seen Bambusa textilis badly damaged. However, for my important screens, I use Bambusa multiplex, just to be safe. I have seen too many people "zone push" with bamboo, only to become disillusioned and give up on bamboo after a couple cold winters.

Re: Freeze Damage

Posted: Sat Jan 28, 2017 1:13 am
by needmore
My in-ground B ventricosa 'Kimmei' was shoot crazy last fall. A flush of nice shoots leafed out followed by another flush of larger shoots. All of the later flush appear to be whacked; the leafed out batch of culms have fully defoliated and the older culms have healthy green leaves. The low was 29.8F or so for a few hours. I'm quite surprised that the earlier flush is defoliated at that temp, they looked more mature than they must be.

Re: Freeze Damage

Posted: Sat Jan 28, 2017 8:40 am
by Glen
needmore wrote:My in-ground B ventricosa 'Kimmei' was shoot crazy last fall. A flush of nice shoots leafed out followed by another flush of larger shoots. All of the later flush appear to be whacked; the leafed out batch of culms have fully defoliated and the older culms have healthy green leaves. The low was 29.8F or so for a few hours. I'm quite surprised that the earlier flush is defoliated at that temp, they looked more mature than they must be.
That is interesting. I am also surprised by that kind of damage at those relatively mild temperatures.

I have noticed that the hardier Bambusa species (like Bambusa textilis) tend to produce culms that elongate fully the first year, but do not branch until the following year. The branch buds remain dormant, the culms just standing there looking like fishing poles through the winter. Those dormant buds are very hardy, and they seem to be able to withstand temperatures that will destroy the leaves on older culms.

Unfortunately, Bambusa ventricosa does not seem to do this. Its culms start branching before they fully elongate. Any culms with soft, actively growing branches are more vulnerable to cold. This winter, we had temperatures of 25 and 22 degrees Fahrenheit. This caused damage, somewhat worse than what you described above, to all my forms of Bambusa ventricosa. Last winter, I think we fell to around 28 degrees a couple times, and received no damage to these same plants. Your damage this year shows that there are complicating factors when it comes to freeze damage.

Re: Freeze Damage

Posted: Sun Jan 29, 2017 4:18 am
by Cooper12
here is my Kanapaha a week into being under snow. Weather was nice today and tomorrow will be as well. i did notice some burnt foliage

Re: Freeze Damage

Posted: Sun Jan 29, 2017 7:26 pm
by Tarzanus
Borinda fungosa - fried 100%
IMG_20170128_131214.jpg

Re: Freeze Damage

Posted: Sun Jan 29, 2017 10:41 pm
by I_am_Ian
Off topic, but why does the south get so much colder than it does here in central California? The winter lows are higher than here yet it's only been below 20 one time ever here back in 1972. We are much farther north but never get as cold as I see some of the record lows in places way more south and close to water. What gives?

Re: Freeze Damage

Posted: Sun Jan 29, 2017 10:48 pm
by Cooper12
I_am_Ian wrote:Off topic, but why does the south get so much colder than it does here in central California? The winter lows are higher than here yet it's only been below 20 one time ever here back in 1972. We are much farther north but never get as cold as I see some of the record lows in places way more south and close to water. What gives?
The west is moderated by the pacific and do not get contenintal air masses where as they do over there so while it's often warmer they can get colder air from the north

Re: Freeze Damage

Posted: Sun Jan 29, 2017 10:49 pm
by Cooper12
Tarzanus wrote:Borinda fungosa - fried 100%
IMG_20170128_131214.jpg
My fungosa goes half way dormant but does not seem to ever burn

Re: Freeze Damage

Posted: Mon Jan 30, 2017 7:53 am
by Tarzanus
By half way dormant you mean it sheds leaves?
Mine does as well in the beginning of the winter, soon after first couple of frosts. Gets yellow and looses 1/3 to 1/2 of leaves. Then it waits for the spring. This year, soil got frozen down to 50cm and hasn't thawed for a month. This week, we'll have first above freezing temperatures since December.