There are numerous resources out there that will determine your hardiness zone but the one I typically refer Canadians to is the Agriculture Canada online app. As is typical of many of our government initiatives, it is somewhat clunky and inefficient, but it means well and actually provides very useful information. This app will allow Canadians to zero-in on their city/region, and even their specific neighbourhood, to determine their hardiness zone, and it also allows users to toggle between the 2000 Hardiness Zone Map and the 1967 version.
It seems that the 1967 version suggests that many Canadians live in a slightly higher hardiness zone than the 2000 version. The 2000 version, which is based on data collected between 1961 - 1990, seems to be somewhat skewed by particularly cold winters in the 70's and 80's. Organizations in the US such as the American Horticulture Society and the US National Arbor Day Foundation have found a similar phenomenon which eventually led to the USDA updating its map in 2012 to reflect generally warmer winters since 1990. Agriculture Canada has yet to update its map.
This is the reason I list my hardiness zone as 6a/6b. It is exceedingly rare for Oakville to experience a low of -20C or colder, and in fact, the coldest winter lows seem to hover around -16C to -18C and remain there for only a few hours during the night. That would put Oakville in zone 6b, though still at risk of an extreme cold snap every 10-20 years, a la January 2014!. Still, even this year, the air temp hit a low of -21C, which would just barely bump Oakville into zone 6a.
Friday, January 31, 2014
Thursday, January 30, 2014
Winter Protection to the Extreme
Growing bamboo and other exotic plants in climates far removed from their native ones typically requires some "man-made" accommodation. For those of us in zones 5, 6, and 7, this essentially means winter protection. This absolutely brutal winter has inspired me to consider the most effective winter protection methods, even those that seem extreme.
First, an admission. I was lazy this year and, relying on the string of mild winters we have had here in Southern Ontario, I thought I could get by with mediocre winter protection. In the spring, I think I will have found that I learned a costly lesson. So, never again. From now on, winter protection will be a top priority!
Below are a number of different means of winter protection, some cheap, simple and easy to implement - others not so much.
1. Use planters that you can move into protected environments during the coldest months
This is of course the simplest winter protection method and something I have done myself with a number of my plants. You need not be relegated to small pots. Planters as big as 20, 30, and 40+ gallons can be moved with some equipment (e.g. a dolly, or wheels attached to the base of the planter). This allows you to grow relatively climate-sensitive specimens that can actually achieve quite a large size. I have seen 14'+ bamboo in large custom planters. Of course, finding a winter home for such plants and planters may prove a bit of a challenge. A well-insulated greenhouse with some added propane/gas heating would be the "gold standard" for over-wintering such plants.
2. Mulch
Mulch is the mainstay of any winter protection program for plants that remain in the ground. Mulch basically helps the soil, and hence the roots and rhizomes of a plant, retain heat and moderate temperature drops. It does this by better absorbing solar radiation than bare soil (or snow for that matter) and by insulating the soil. For example, although the day's high may only be -8C, to many bamboo that compares very favourably with a low of say -18C. Mulch will help the soil spend more time at -8C (or higher because of its absorption of solar radiation) and less or no time at -18C.
People tend to be very loyal to the mulch they use, and there is no single perfect mulch out there; however, when considering ONLY winter protection, Straw has the best insulation capacity. This is also why rodents like to nest in it. Straw also tends to rot easily. I have read that applying straw in early winter, after a solid frost (mid/late November for most of us in Southern Ontario), helps prevent rot and rodent infestation. While one could leave the straw in their planting beds in the spring, I would rather remove it and dispose of it.
Another admission. I have yet to use straw. I typically mulch with 6-8"+ of a pine mulch and shredded leaf combination. The insulation is relatively good and I don't have to pick it up in the Spring. I would use straw on zone 8 bamboos, on bananas, and on palms (but I don't have any of those yet!).
3. Tarps, Blankets, Coverings of Some Kind
Depending on the hardiness of the varieties grown, covering bamboo with some sort of tarp, blanket or thick poly sheet may be necessary.
This year, I used a cheap clear plastic sheet on my P. Spectabilis and I am sure I will pay the price for it. For most plants, I would use a 3 to 5 mil poly sheet, or as it is know in agricultural circles, "overwintering film".
If you are growing a marginal bamboo for your climate, I would instead invest in a high-quality frost blanket. Why go to all the effort of growing an exotic plant and not invest in protecting it? DeWitt is a popular manufacturer of frost blankets which come in weights of up to 3.0 oz.. The 3.0 oz "Ultimate" blanket claims "up to 10 degrees (F) of frost protection" compared to the ambient temperature. Expensive? Sure. Extreme? Somewhat. Worth it for a plant that you have spent two or three years nursing and that would be difficult to replace? Absolutely.
This year, I also used a tent-like woven poly frost blanket for my F. Scabrida. These are great as they are easy to set up and use, but the largest of these particular tents that I have seen seems to be about 4 feet high. I suppose one could perhaps bend over a 7 or 8 foot tall bamboo and cram it in there, but obviously, plants taller than about 8 feet and wider than about 3 feet will not fit in these tents.
Custom build structures using chicken wire and filled with some insulating material are also typically very effective. See this post on Steve Lau's blog for an example.
On a final note, I have read that light transmission is probably not important for bamboos during the winter as they remain dormant and do not photosynthesize sunlight. This is why bamboo covered in snow for three months typically looks ok in the spring.
4. Chemical Treatments
Now we are really entering the realm of extreme winter protection. There are two chemical treatments that one could use to help overwinter bamboo and other plants. These are both "anti-dessicants' but one is meant for leaves and the other for roots. These essentially help a plant hold onto its moisture and prevent dessication by coating the leaves and roots with a waxy yet bio-degradable film. Wilt Pruf is the most popular anti-dessicant for leaves. Root Zone is an anti-dessicant (or anti-transpirant if you prefer) for the roots of a plant.
5. Radiant Heating (experimental)
So you've mulched, tarped, used anti-dessicants, and you are still worried. Well then you probably shouldn't be growing what you are trying to grow in the climate zone you're trying to grow it!! But let's assume you love the challenge and damn it, you want the yard of your cottage in the Muskokas (zone 5a/b) to look like Tahiti. Ok, there is one last extreme winter protection method I can suggest - though it is experimental and I have never tried it.
Basically, the idea involves the use of outdoor spotlights or "brooder lights" fitted with infrared heat lamps. Typically, these light fixtures can support anywhere from 150W to 300W bulbs. 175W and 250W infrared bulbs are fairly widely available. During extremely cold periods, one could conceivably aim one or more lights at a plant. Because the heat is of the radiant type, the plants would be heated so long as they were exposed to the light.
There are a number of issues with this idea. Some of these are:
1. Cost and Complexity - obviously difficult and expensive to set up and operate
2. Heat Damage - if the lamps are placed too close to the plant, if they blow onto the plant, or if they are simply too powerful, heat damage is a risk. Fire is also a risk.
3. Complaints - Neighbours may not take too well to a bank of red lights glowing in your yard throughout the night, though if you want to get really extreme, you could avoid this by getting ceramic dull emitter infrared bulbs, which emit no visible light, only infrared light.
If you have tried all of the above and your plant still dies from cold-related injury, then you may be trying to grow an tropical Orchid outdoors in Winnipeg. I can't help you!
First, an admission. I was lazy this year and, relying on the string of mild winters we have had here in Southern Ontario, I thought I could get by with mediocre winter protection. In the spring, I think I will have found that I learned a costly lesson. So, never again. From now on, winter protection will be a top priority!
Below are a number of different means of winter protection, some cheap, simple and easy to implement - others not so much.
1. Use planters that you can move into protected environments during the coldest months
This is of course the simplest winter protection method and something I have done myself with a number of my plants. You need not be relegated to small pots. Planters as big as 20, 30, and 40+ gallons can be moved with some equipment (e.g. a dolly, or wheels attached to the base of the planter). This allows you to grow relatively climate-sensitive specimens that can actually achieve quite a large size. I have seen 14'+ bamboo in large custom planters. Of course, finding a winter home for such plants and planters may prove a bit of a challenge. A well-insulated greenhouse with some added propane/gas heating would be the "gold standard" for over-wintering such plants.
2. Mulch
Mulch is the mainstay of any winter protection program for plants that remain in the ground. Mulch basically helps the soil, and hence the roots and rhizomes of a plant, retain heat and moderate temperature drops. It does this by better absorbing solar radiation than bare soil (or snow for that matter) and by insulating the soil. For example, although the day's high may only be -8C, to many bamboo that compares very favourably with a low of say -18C. Mulch will help the soil spend more time at -8C (or higher because of its absorption of solar radiation) and less or no time at -18C.
People tend to be very loyal to the mulch they use, and there is no single perfect mulch out there; however, when considering ONLY winter protection, Straw has the best insulation capacity. This is also why rodents like to nest in it. Straw also tends to rot easily. I have read that applying straw in early winter, after a solid frost (mid/late November for most of us in Southern Ontario), helps prevent rot and rodent infestation. While one could leave the straw in their planting beds in the spring, I would rather remove it and dispose of it.
Another admission. I have yet to use straw. I typically mulch with 6-8"+ of a pine mulch and shredded leaf combination. The insulation is relatively good and I don't have to pick it up in the Spring. I would use straw on zone 8 bamboos, on bananas, and on palms (but I don't have any of those yet!).
3. Tarps, Blankets, Coverings of Some Kind
Depending on the hardiness of the varieties grown, covering bamboo with some sort of tarp, blanket or thick poly sheet may be necessary.
This year, I used a cheap clear plastic sheet on my P. Spectabilis and I am sure I will pay the price for it. For most plants, I would use a 3 to 5 mil poly sheet, or as it is know in agricultural circles, "overwintering film".
If you are growing a marginal bamboo for your climate, I would instead invest in a high-quality frost blanket. Why go to all the effort of growing an exotic plant and not invest in protecting it? DeWitt is a popular manufacturer of frost blankets which come in weights of up to 3.0 oz.. The 3.0 oz "Ultimate" blanket claims "up to 10 degrees (F) of frost protection" compared to the ambient temperature. Expensive? Sure. Extreme? Somewhat. Worth it for a plant that you have spent two or three years nursing and that would be difficult to replace? Absolutely.
This year, I also used a tent-like woven poly frost blanket for my F. Scabrida. These are great as they are easy to set up and use, but the largest of these particular tents that I have seen seems to be about 4 feet high. I suppose one could perhaps bend over a 7 or 8 foot tall bamboo and cram it in there, but obviously, plants taller than about 8 feet and wider than about 3 feet will not fit in these tents.
Custom build structures using chicken wire and filled with some insulating material are also typically very effective. See this post on Steve Lau's blog for an example.
On a final note, I have read that light transmission is probably not important for bamboos during the winter as they remain dormant and do not photosynthesize sunlight. This is why bamboo covered in snow for three months typically looks ok in the spring.
4. Chemical Treatments
Now we are really entering the realm of extreme winter protection. There are two chemical treatments that one could use to help overwinter bamboo and other plants. These are both "anti-dessicants' but one is meant for leaves and the other for roots. These essentially help a plant hold onto its moisture and prevent dessication by coating the leaves and roots with a waxy yet bio-degradable film. Wilt Pruf is the most popular anti-dessicant for leaves. Root Zone is an anti-dessicant (or anti-transpirant if you prefer) for the roots of a plant.
5. Radiant Heating (experimental)
So you've mulched, tarped, used anti-dessicants, and you are still worried. Well then you probably shouldn't be growing what you are trying to grow in the climate zone you're trying to grow it!! But let's assume you love the challenge and damn it, you want the yard of your cottage in the Muskokas (zone 5a/b) to look like Tahiti. Ok, there is one last extreme winter protection method I can suggest - though it is experimental and I have never tried it.
Basically, the idea involves the use of outdoor spotlights or "brooder lights" fitted with infrared heat lamps. Typically, these light fixtures can support anywhere from 150W to 300W bulbs. 175W and 250W infrared bulbs are fairly widely available. During extremely cold periods, one could conceivably aim one or more lights at a plant. Because the heat is of the radiant type, the plants would be heated so long as they were exposed to the light.
There are a number of issues with this idea. Some of these are:
1. Cost and Complexity - obviously difficult and expensive to set up and operate
2. Heat Damage - if the lamps are placed too close to the plant, if they blow onto the plant, or if they are simply too powerful, heat damage is a risk. Fire is also a risk.
3. Complaints - Neighbours may not take too well to a bank of red lights glowing in your yard throughout the night, though if you want to get really extreme, you could avoid this by getting ceramic dull emitter infrared bulbs, which emit no visible light, only infrared light.
If you have tried all of the above and your plant still dies from cold-related injury, then you may be trying to grow an tropical Orchid outdoors in Winnipeg. I can't help you!
Tuesday, January 28, 2014
Runners more cold-hardy than clumpers
I came across this interesting abstract that essentially seems to conclude that runners (monopodial rhizomes) are more cold-tolerant than clumpers (sympodial rhizomes) by looking at snow and ice damage during a particularly treacherous winter in China. This is consistent with the experience of those at Needmore Bamboo. They don't seem to have had much luck with Fargesia's in Zone 5b.
I have had pretty good performance from my F. Scabrida in zone 6a/b, and my new F. Robusta seemed to do fairly well early in the winter before I moved it into the garage, but I think planting location, fertilizer, mulch, and winter protection have a lot to do with my modest success.
I have had pretty good performance from my F. Scabrida in zone 6a/b, and my new F. Robusta seemed to do fairly well early in the winter before I moved it into the garage, but I think planting location, fertilizer, mulch, and winter protection have a lot to do with my modest success.
Maui Ocean Center - Bambusa Vulgaris Vittata
Saw an interesting variety recently on a trip to Maui. Thanks to Steve L. for identifying it as Bambusa Vulgaris Vittata ("Golden Painted Hawaiian Bamboo"):
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I originally thought it might be P. Vivax Huangwenzhu Inversa given the unique coloration of the culms.
I do know that this is one variety that will not tolerate zone 5, 6, or likely even 7. Those few Canadians in a solid zone 8 might have a fair shot with this variety, though it would still likely require some winter protection. This basically means residents of the lower-lying coastal regions of Greater Vancouver and the lower-lying, southern part of Vancouver Island (and most of the little islands in between).
I originally thought it might be P. Vivax Huangwenzhu Inversa given the unique coloration of the culms.
I do know that this is one variety that will not tolerate zone 5, 6, or likely even 7. Those few Canadians in a solid zone 8 might have a fair shot with this variety, though it would still likely require some winter protection. This basically means residents of the lower-lying coastal regions of Greater Vancouver and the lower-lying, southern part of Vancouver Island (and most of the little islands in between).
-34C With the Windchill - Brutally Cold!
Today, the air temp hit a low of -21C, -34C with the windchill - not exactly bamboo-friendly weather. This winter has been BRUTAL! Absolutely the coldest I have experienced in my 7 years in Southern Ontario.
I have five plants in the ground right now. Three others I managed to pot and bring into the garage before the really bad cold hit. Since then, the garage has become so cold that I took a number of my more sensitive plants indoors. This means they have come out of dormancy, which will be tricky to deal with.
Of the ones in the ground, here's a re-cap:
1. P. Aureosulcata 'spectabilis' - Mulched heavily with pine chips and leaves, but I could have done better protecting it - just a plastic trap wrapped and taped around it. Leaf burn is pretty bad. I learned my lesson this year. Will cover it better next year if it survives. Here it is pre-winter:
Here it is now:
2. P. Rubromarginata - Mulched heavily with pine chips and leaves. Covered with one of those thick plastic garment bags, which I managed to zip up almost fully. It is buried under a foot of snow so I have no idea what is going on under there. Here it is pre-winter:
3. F. Scabrida - Mulched heavily with pine chips and covered with one of those tent-like frost covers. Can't get a good look at the leaves but looks like leaf burn has set in. Here it is pre-winter:
Not much to see now:
4. P. Parvifolia - Mulched heavily but left unprotected. This one was weak going into the winter as it was a plant that I brought in from a friend in Rochester, NY. Since you're not allowed to bring soil across the border, this went about 6 hours essentially bare root, though the roots were wrapped in wet newspaper and bound with plastic wrap. One of the culms died off early on. The other was hanging by a thread. My only hope is that the root ball is viable. Here's a pic of it during the recent ice storm:
5. P. Atrovarginata - Mulched heavily but this one was also from Rochester and also very weak going into the winter. It essentially died to the ground before winter hit. Low expectations for this one. No photo because it's just a dead culm sticking out the ground.
Fortunately, I managed to pot and move many others into more protected environments. These are in my garage, where it still gets down to about -7C on the coldest nights:
F. Robusta
P. Nigra 'Othello'
P. Aurea "Holochrysa':
These I moved into the house:
a small P. Parvifolia (pretty sad looking but it's been surprisingly stable for several months - hope it perks up)
P vivax huangwenzhu inversa (now bursting with new leaves - only one week after bringing it indoors)
P. edulis 'moso' (just a small seedling - note three tiny shoots emerging again only one week after bringing it indoors)
P. kwangsiensis (has been in very bad shape basically since I got it - I do see one tiny new shoot)
Semiarundinaria Fastuosa
Indocalamus Tessellatus
Pleioblastus viridistriatus (?) - this one I left for dead but to my surprise it is slowly coming back. Stunning yellow/lime coloration
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Pseudosasa owatarii (?)
another ground cover bamboo I haven't been able to identify (any help would be appreciated)
So there you have it. My complete collection thus far. I aim to add 3-4 plants this spring, perhaps more, depending on how many I lose this winter.
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