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What Happened ???

Posted: Sat May 24, 2014 1:25 am
by dgoddard
Unlike previous years, my bamboo seemed to hold its leaves longer than usual. Finally last year's culms in my groves started to green up and put out new leaves. And of course there were the usual number of rhizomes trying to widen the grove. But my largest most vigorous grove held its dead leaves even longer and as best I can tell nearly if not absolutely all of last years culms are dead. New culms are coming up throughout the grove but being more slender I doubt that any will go as high as last year.
140523_Dead_culms.JPG
As the photo shows the new upcoming culms are about half the height of last years and I doubt they will go much higher and the vast mass of last years culms appear dead even though my other groves have mostly greened up.

Last winter here was not particularly cold and the only difference is that this grove is the least sheltered from wind. It is also the closest to an area which is basically untended wild grasses and weeds. The grove is about 20 to 25 feet from the sewage lagoon and on ground about 8 to 10 feet higher. Nothing known to be toxic is discharged into our sewage system nor has anything disrupted the normal bacterial action in the lagoon. The grove could have extended roots into a layer watered by the lagoon and that water would probably have been high in phosporus and nitrogen from what I know about sewage. The grove retained green leaves just as long as my other groves but after the leaves died, apparently so did the culms they grew from. What would have caused this ???

If it were disease, I would think that the new growth within the grove would not have happened, although there are no new culms as thick as what I saw for last year. However the rhizomes running out of the grove seem to have put out normally and I dug up most of those to start a new grove and all have come through the transplanting and are doing well.

The new extension I planted at one end is growing normally Of course it does not yet share the same root mat. The only thing that comes to mind is that perhaps something affected a large part of the root mat of the main part of the grove.

Of all my groves this one is growing in the one spot in my lawn that had really good soil that grows lots of grass. The picture shows only about half of the grove but the density of new and old culms in the grove is uniform throughout.

Any suggestions as to what might have done this? I live on the boundary of climate zones 5 and 6 and the variety in all my groves is Phylostachys Aureao Sulcatta obtained from a well established mature grove locally. I am wondering if some sort of vermin might have attacked the existing root mat sometime last year or even last winter and damaged it. We do have a lot of voles and moles around here.

Re: What Happened ???

Posted: Sat May 24, 2014 1:35 am
by johnw
Can you tell us more about your past winter - winds, lowest temps etc./

johnw

Re: What Happened ???

Posted: Sat May 24, 2014 2:06 am
by stevelau1911
When you get prolonged temperatures well below average for an entire winter with exceptional extremes, it is reasonable to expect a lot of the roots and rhizomes underground to be dehydrated and even killed off. I'm finding some turned up rhizomes which are oozing an orange colored liquid which is a sign that the freeze this year went deep enough to do damage underground. If you have aureosulcata, it should bounce back to its previous size by next year because this species produces one of the most vigorous root systems for bamboo.

Polar vortexes which make winters unusually cold, and long are pretty uncommon, especially ones that last several months so I believe your bamboo should eventually re-gain it's vigor.


One reason I believe this is because my edulis bicolor which was under a greenhouse and double solarized produced shoots pretty quickly, and those shoots are rising pretty quickly with the normal vigor you would expect.

Every other grove which was exposed to the winter seems to have very lazy shoots which likely won't grow very tall, even if they are coming out at a decent diameter. The top damage is definitely a part of this, but this winter, it got cold enough to freeze the ground even though it was well mulched. I believe this winter may have killed off all my musa basjoo bananas which are supposed to be hardy to zone 5.

Re: What Happened ???

Posted: Sat May 24, 2014 2:47 am
by dgoddard
In the 6 or so years we have been growing bamboo only one winter was severe with sub zero temperatures (0 to 010) every night for a week and lots of wind. That year all the above ground growth in all the groves was killed but the groves all came back vigorously in the spring although none of the groves were as developed as this one. Last winter was not unusual at all although we may have had a bit more high wind and this grove is on the windward side but when we had wind it was not particularly cold also the grove stayed green throughout the winter and only this spring did the leaves finally turn dull green and the die, although they did not drop off until just a couple to 3 weeks ago. The new extension of the end of this grove which gets as much wind as any of it had only 1 years growth and is unaffected. The early spring this year was not as wet as usual but not a drought and we are getting pretty good rain now.

So if what I am seeing is just winter kill, what would be the best care to give the grove. Should I cut off all the dead culms.... that is a lot of work and would have been better done when I could just have laid the whole thing down. Now it would involve going through a very thick grove.

Re: What Happened ???

Posted: Sun May 25, 2014 12:12 am
by dependable
Looks like winter kill to me. Best to leave grove be until new shoots are up and hardened off. Might have been nice to clear cut earlier, but too late now if you want grove to recover well.

It was a tough winter. The stand would not be harmed, I think, in letting winter killed culms stand and rot, if you can stand the look, they will get brittle and knock down in a few years, adding to soil.