Needmore Bamboo Co.
 
       
     March 1, 2008
     Another winter is nearly completed and today I made some cold damage observations.   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.
     My initial observation is that the different types of winter weather we have seems to impact different species in different ways.   Last winter we had a late season deep freeze that saw temperatures below +32F for 15 consecutive days, with a low of around -5F at the end of this freeze.  Some of the bamboo that had held up well to lower temperatures in prior years, showed significant damage after the deep freeze. The prior couple of winters we had much colder low temperatures but shorter deep freezes and the damage to bamboo was widespread with only a couple of species retaining green leaves.  This year I am seeing more damage to some species that generally can take the severe lows, while others look better than in prior years.   These observations reinforce my opinion that temperature ratings are not reliable indicators of winter performance - at least in areas that experience prolonged cold periods every winter.   Temperature ratings may be appropriate for those parts of the country that experience subfreezing temperatures rarely, and for only a few hours.
     I would describe the winter of 2007-08 as mild in terms of low temperature extremes but overall it seemed unusually cold.    The lowest temperature that I have recorded has been just shy of -2F.   However we have been to 0F 2-3 nights, and have also seen lows between +4F and +10F perhaps another 8-10 nights.   I am recalling this information from memory rather than field notes so I may be off slightly on the number of single digit nights.   As of today we have seen 15 consecutive days of below normal temperatures and this perhaps best characterizes the winter - colder than normal, but not severely cold.   There has been our normal <10 inches of snow but far more ice than normal and the recent freezing rained burned lots of leaves.   We have also had a few instances of the real killer, strong cold winds of up to 40-50 mph on 3 different occasions.
           This year I am seeing a few species that are clearly top killed but for the most part the damage appears to be limited to leaves and branch/culm tips.   It can be difficult to ascertain the degree of leaf damage, bamboo with tan/blond leaves very likely have branch & culm damage and may well be top killed.  Plants with leaves that are sage colored are probably recently damaged and on their way to dropping off but if there are an appreciable number of fresh green leaves on other branches then the damage is likely minor.      Although it can be very difficult to tell for certain, on some species close inspection will reveal intact dormant leaf buds and this tells the story of what you can expect in the spring.   If the leaf buds are dead then the culm is likely dead as well.   If a significant majority of culms are dead then in all likelihood the spring culms will be smaller than the prior years growth.   Ah, such is the cycle of topkill!

     The dormant leaf buds are the scaly looking things on the branchlets. Sometimes these will have started to elongate during a warm up and they will be easier to review for damage.   In most every hardy genus except Phyllostachys the leaf buds are well concealed and it is very tough to evaluate their condition.   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.
  
  A Report Card
     Below are my current damage estimates thus far for the 2007-08 winter season.


Less than 5% leaf burn:
Fargesia dracocephala 'Rufa'
Phyllostachys angusta
Phyllostachys aureosulcata
Phyllostachys manii 'Decora'
Phyllostachys propinqua 'Li Yu Gan'
Phyllostachys stimulosa
Phyllostachys vivax 'Huangwenzhu'
Sasa oshidensis
Sasa senanensis

Less than 10% leaf burn:
Phyllostachys atrovaginata
Phyllostachys aureosulcata 'Harbin Inversa'
Phyllostachys aureosulcata 'Spectabilis'
Phyllostachys rubromarginata
Pleioblastus juxianensis


10% - 20% leaf burn:
Shibataea chinensis

20% - 30% leaf burn:
Arundinaria gigantea - all forms
Brachystachyum densiflorum
Phyllostachys arcana
Phyllostachys aureosulcata 'Alata'
Phyllostachys bissetii
Phyllostachys bissetii 'Dwarf form'
Phyllostachys flexuosa
Phyllostachys glauca 'Notso'
Phyllostachys heteroclada 'Solidstem'
Phyllostachys humilis
Phyllostachys parvifolia
Pleioblastus oleosus


30% - 50% leaf burn:
Bashania fargesii
Indocalamus latifolius
Phyllostachys aureosulcata 'Aureocaulis'
Phyllostachys glauca 'Yunzhu'
Phyllostachys heteroclada 'Straightstem'
Phyllostachys iridescens
Phyllostachys makinoi
Phyllostachys nigra 'Megurochiku
Phyllostachys nuda
Phyllostachys nuda 'Localis'
Semiarundinaria okuboi
Shibataea kumasaca


50% - 80% leaf burn:
Indocalamus longiaritus
Indocalamus tessellatus - 'Hamadae' form 90% burn
Phyllostachys dulcis
Phyllostachys glauca
Phyllostachys nigra 'Bory'
Phyllostachys nigra 'Henon'
Phyllostachys nigra 'Punctata'
Phyllostachys nigra 'Shimadake'
Phyllostachys vivax 'Aureocaulis'
Sasa nagimontana
Sasaella ramosa
Semiarundinaria fastuosa, fastuosa 'Viridis'


80% - 100% leaf burn but buds look viable:
Hibanobambusa tranquillans & 'Shiroshima' - both forms
Phyllostachys nigra
Phyllostachys viridis
Phyllostachys vivax
Pleioblastus chino
Sasa megalophylla
Sasa palmata
Semiarundinaria makinoi


The big losers - topkill likely:
Phyllostachys aurea, aurea 'Koi'
Phyllostachys aureosulcata 'Harbin' - Consistently gets damaged earlier than the other aureosulcata forms, +5F limit?
Phyllostachys edulis
Phyllostachys elegans
Phyllostachys heteroclada 'Purpurata'
Phyllostachys lithophylla
Phyllostachys nigra 'Hale'
Phyllostachys viridis 'Houzeau, viridis 'Robert Young'
Phyllostachys vivax 'Huangwenzhu Inversa'
Pleioblastus amarus
Pleioblastus argenteostriatus
Pleioblastus simonii
Pseudosasa japonica
Pseudosasa longiligula
Sasa cernua
Semiarundinaria yashadake 'Kimmei'
**The ground covers - Pl. fortunei, Pl. pygmaeus - all forms, Pl. viridistriatus all top killed

  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.