February 21, 2010
     Because I live right on the climactic edge of being able to grow big bamboo and being able to grow medium size bamboo I tend to evaluate the severity of winter in terms of bamboo damaging extreme cold temperatures.   If we stay above 0F all winter then I happily proclaim that we had a mild winter, a statement that often engenders looks of 'this boy's crazy it's been colder than a ....(fill in the blank)' .  Conversely, if we have unusually mild temperatures for most of the winter but also experience a brief subzero spell, I'll complain about how severe the weather was.  For the first time that I can recall, I would describe this as a seriously cold winter even though my lowest recorded temp thus has been +1.77F.  Multiple long stretches of consecutive days where the high stays below +32F so I would expect to see lots more leaf burn than I currently do, the missing ingredient being lots of cold, dry, strong winds.  
     My impression is that we have experienced below normal temperatures consistently since December of 2008; cold temps (-8F twice) and strong winds in the winter of 08-09 causing lots of bamboo damage followed by a mild summer and a normal fall.   But despite our continued sub average temperatures this winter of 09-10 I am seeing some species that are retaining green leaves for the first time ever with minimal top damage limited to just the tenderist bamboos.   If we stay above +5F for the next few weeks I will expect to see notable increases in the size of the spring 2010 new canes and that is what I long for each year.  
       If your bamboo has burned leaves and you are concerned about the health of your bamboo, I would suggest that you examine the dormant leaf buds.  These are the scaly looking things on the branchlets. Sometimes they will have started to elongate during a warm up and they will be easier to review for damage.  Close examination may reveal that the buds are still firm and green in which case they will likely be viable.   If they are easily flicked off or appear to have poor coloration they may well be dead.   In any case don't do anything now, wait until late spring to see if they produce new leaves.   Dead culms will become apparent in time as they fade to blonde/tan and these may be culled when obviously dead but they can be helpful in protecting new shoots so you may wish to wait until after the new spring culms are leafing out before you cut the old culms out.
 
Throughout this website when speaking about bamboo hardiness issues, I want to be clear about 2 things:    1) Bamboo will sustain cold damage by factors other than subzero temperatures (see Winter Damage)     2) Young plantings - less than 3 years in the ground - are more susceptible to cold damage.
 
  A Report Card
     Below are my current damage estimates thus far for the 2009-10 winter season, usually I'll list species grouped by the degree of damage but to avoid LOTS of typing I will list only those with notable damage as nearly everything I have is in very good shape - less than 20% leaf burn.   Last summer I intensified my efforts at removing under performing species so there will be many species that I have included in the past but am no longer growing.


20% - 40% leaf burn:
Phyllostachys Aureosulcata 'Harbin'
Phyllostachys violescens
Phyllostachys viridis & 'Robert Young'


40% - 60% leaf burn but buds look viable:
Hibanobambusa tranquillans & 'Shiroshima' - both forms
Phyllostachys bambusoides 'Allgold'
Phyllostachys elegans
Phyllostachys praecox
Phyllostachys viridiglaucescens
Pleioblastus chino

60% - 80% leaf burn with some buds remaining viable:
Fargesia robusta 'Wolong'
Fargesia scabrida
Phyllostachys edulis
Pseudosasa viridula

The big losers - topkill likely:
Chimonobambusa quadrangularis
Chimonobambusa tumidissinoda
Phyllostachys heteroclada 'Purpurata'
Phyllostachys lithophylla
Phyllostachys meyerii
Phyllostachys nidularia seedling form named 'Double Node'
Pleioblastus amarus
Pleioblastus linearis
Pleioblastus simonii
Pseudosasa longiligula

  If you have questions about a particular species not listed above please feel free to email me and I'll check it out for you. In some cases I just can not tell the status of the species and I have omitted it from the list.