Protecting bamboo during the winter

Most of temperate bamboos are quite cold hardy, but there are exceptions and every plant’s cold hardiness has its limits. To prevent damage during the cold months of winter, it’s often best to offer your plants at least some protection to prevent loosing your bamboo.

Most common causes of winter damage

Drought stressed Moso got severely burnt during the cold weather

Drought stressed Moso got severely burnt during the cold weather

Beside the cold itself, sometimes there are other causes of winter damage. In late fall, bamboos go through a preparation period in which their cold hardiness improves considerably. Their growth and transpiration halts to a minimum, some can even shed some of their leaves. When soil is cold, sometimes even frozen, water mobility from roots towards the leaves is extremely difficult process which can even completely stop if the soil or any part of bamboo culm gets completely frozen. At that point, each additional leaf that requires water, means that the plant loses more water than it can replenish. It is also good Idea to mulch the soil around the bamboo with layer of dry leaves, grass or wood shavings. Mulch does attract rodents, which can sometimes cause more damage than the mulch prevents. If you fertilize in late autumn, there is a possibility that bamboo fails to enter the winter preparation and continues to actively grow. During growth it’s much more delicate and can be damaged by either drought, heat or cold. Plants that were already stressed during previous growing season are often more prone to cold damage.

How cold is too cold?

Snow covered Borinda fungosa. Late fall shoots are toasted since first frost

Snow covered Borinda fungosa. Late fall shoots are toasted since first frost

There’s no answer to that one. Cold damages plants, but it usually doesn’t “work” alone. If it’s cold and the weather is overcast or if there’s fog and no wind, there will be much less damage, compared to clear sunny windy and frigid day. Wind can dry out even the most prepared leaves that are coated with thick layer of wax. Sun warms up the dark green foliage that heats up readily, transpiration rate goes up and the roots can’t supply enough water. When you combine all three, cold, sun and wind, the effect is by far the worst. I’ve lost several bamboos in those conditions.

Piled-up snow – best winter protection

Raised bed covered with PVC tunnel and snow insulation. PVC tunnel collapsed due to snow cover weight. Plants were completely unharmed.

Raised bed covered with PVC tunnel and snow insulation. PVC tunnel collapsed due to snow cover weight. Plants were completely unharmed.

When snow falls over bamboo, it will easily bend and soon, snow covers the bamboo completely. That is bamboo’s natural defense against winter extremes and it works extremely well. If there is at least some snow before the cold hits, it’s best you use it! By tarping the bamboo down to the ground, it is easier to cover it with snow. I usually just shovel up a pile of snow over it, and hope enough snow falls before the bitter cold arrives. Tarping bamboo to the ground is necessary when the plant gets larger, but usually gets impossible as the plant matures. Snow covered bamboo makes the air around bamboo leaves warmer than the air above, regulates moisture and prevents desiccation. It is also dark and keeps only minimal transpiration.

Thick layer of snow effectively protects the plants below

Thick layer of snow effectively protects the plants below

All the snow covered bamboos survived the cold blast completely intact. Soil did not freeze under snow insulation and my protected bamboos only suffered minor culm and branch breakage. The much taller and robust bamboo culms that remained exposed got damaged. My Moso seedling that got drought and heat stressed during the summer is going to show substantial winter damage. Tender Phyllostachys aurea is fried up to 50% and Phyllostachys aureosulcata ‘Spectabilis’ (Lamatempel) with no damage whatsoever. All my smaller other bamboos got protected by themselves – snow laid them flat and since the snow cover got thick enough, they remained safe during the severe winter weather with temperatures down to -16°C and powerful dry wind.

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6 thoughts on “Protecting bamboo during the winter

  1. Rytis

    Hello,

    Thanks for the sharing of your experience. It was very interesting and useful to read. I am going to plant bamboo ‘Spectabilis’ in my garden. The question is when to plant seedling? Should I keep them in the pots until next spring, or it is better to plant to the ground this year? Our winters in Lithuania usually have several days close to -20 C. Sometimes with snow, sometimes without. So, how about first winter for young (1st year) seedlings? Thank you in advance for your answer

     
    Reply
    1. tarzan tarzan

      Phyllostachys aureosulcata ‘Spectabilis’ is quite hardy and can withstand short periods of -20°C. There is something else, I would be cautious about. You have mentioned Spectabilis seedlings, which are, by my knowledge, very unlikely. Phyllostachys aureosulcata sometimes flowers, but it doesn’t give viable seeds. It is unknown when it will start it’s gregarious flowering, which happens once in 100 years or so. If you are buying the seeds online, there are many scammers that will sell you Phyllostachys edulis ‘Moso’ seeds as something more exotic. Moso is, at least for me, even more fascinating and rewarding, especially when grown from seed, but is way too tender to survive harsh conditions. Perhaps it would survive -15°C for a short period of time and would get completely defoliated at -20°C. My seedling is showing a lot of damage this year after -17°C. It is also true it was stressed out by voles that uprooted it and hot dry summer which didn’t help during the cold.
      You should get your bamboo (Spectabilis should be more than OK for your climate) as a division taken from an established bamboo. I have bought mine online from an eBay shop, located in Germany. You can plant it outside in the spring and it should grow enough during the year to survive the first winter. Just in case, you can always pile up some snow above it, before temperature dips too low.

       
      Reply
  2. Rytis

    Hi again,
    You are right – I’m not sure I’v bought right seeds. Seller is located in Cyprus. So, I’m not sure is it better than China 🙂
    Thanks to your answer I found seller of seedlings in Germany. I think I’ll buy one. Also, I’ll try to grow several seedlings from my seeds and to check results 🙂 Germination was quite successful
    Good luck

     
    Reply
    1. tarzan tarzan

      You can make a rough identification by the appearance of the seeds. If they were large, I would say they are most likely from Moso. Chinese sell those in bulk quantities and sellers all around the world make smaller packages and sell them – sometimes as rare and exotic cultivar seeds. You never know what you get, but it’s usually Phyllostachys pubescens Moso, because it flowers sporadically and it gives a lot of fertile seeds.

      During first year, your seedlings should grow into small little bamboo bushes. Year later, they usually start running and will also start showing some Phyllostachys features. In a few more years, you will be able to see more details and as the bamboo matures, you will be able to ID it.
      If some of the seedlings show extra features like leaf variegation, it should be evident from the very beginning. Culm coloration and culm related special treats become evident much later, 4 or even 5 years after germination.

      Browse around my posts, I’ve had variegated seedlings and grown seedlings from various bamboos. I’m sure you can find useful information about growing your small seedlings. If they are in fact Moso seedlings, you will need some luck, they can be tricky and hard to please. 🙂 Good luck!

       
      Reply
  3. Rytis

    One more question. Is it possible to find a reliable feature of ‘Spectabilis’ species in the first year? If not, in which year it is possible?

     
    Reply
    1. tarzan tarzan

      First year, usually the shoots are at least pencil size and the green sulcus is already visible. Some of the leaves can have thin white stripe, but they are usually rare and overall, foliage is dark green. Even the smallest culms have an aureosulcata feature – rough surface. It almost feels like sandpaper.

      Since there’s no way you can grow it from seed, the only way to acquire it is by rhizome division. All the features should be visible the first year. With seedlings, you need to wait a few years and I guess it would take 3 to 4 years to see the details.

       
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