Uncovering Bamboo?

[canadianplant]

It turns out, bamboo loves it here. IT thrives through the spring, right to december, when it needs to be protected. I bend it to the ground, bury it in leaves, and tarp it, then let the inevitable snow fall do the rest.

Besides last years mistake (not putting the tarp directly on the leaves, I left a huge air gap, which did some damage), I have had some great success, epsecially with my F Rufa (or is it now F sp. "Rufa"? ), which has been in the ground for 3 winters, going onto its 4th summer.

THe problem I have, is deciding when the best time to uncover them. Last year I did it, and left them ucovered in some nasty windchill, and the tops fried. Im also having trouble getting a good method to ucovrering them. SHould I take the majority of the leaves off, and leave it tarped for a few days? Should I leave it uncovered during non windy days and nights, and cover it when the wind picks up?

I know that I shouldnt remove a good 6 inches of the leaves around the base, so that I dont let the ground heat up too much, get it to shoot, and have the shoots die, due to cold weather. I am also aware, that after 2 - 4 months of protection, will leave it a bit "weak" to sun, and giving it full sun right off the bat can stress it out as well.

The bamboo is question, is a 4th season Fargesia Rufa, and a 3rd season Phyllostachys Areosulcata alata. The alata put out a good 13 culms when I planted it, but due to the stress, and partial top kill last spring, it did not shoot at all, instead it almost entirely leafed back out.

A note: The temps can get decent before the snow melts entirely. SInce we usually have a 3 foot snow pack, it takes a bit of time to melt, so using the melting snow as a guide is IMO, unreliable here. Also, once we hit February, the temps start to moderate, and each passing week, there is a less and less chance of a severe drop in temps. Once march hits, Im usually out of the woods from any temps dropping below - 15C.

Any advice would be welcomed

[stevelau1911]

I think the easiest way to tell when you need to uncover it is by getting a cheap weather station, and sticking a sensor under a couple of the tarps which will let you know which should have very accurate readings as long as the device is blocked from sunlight so a sunny day doesn't heat it up. In the last month or so, it has hung between 5-9C with a slight downward trend under one of my tarps so I doubt it will ever drop below freezing as average temperatures should already be on the rise, but since it seems to be holding off the cold extremes, I believe it should also have the ability to hold in the cold by spring, delaying the shooting season while the tarp is still on because warm days don't seem to raise the tarp temperature as much anymore.

I plan on uncovering by around late February for good given that the 15 day forecast looks safe, but in your climate, you can probably leave a tarp on until April if your shoots don't appear until May because they really don't suffer while they are under a tarp especially if you are using transparent ones.

During a heat wave in early spring, I really doubt the tarped bamboo will be warmer than the outdoor temperature from what I have seen so far with my sensor results, but it's not hard to untarp it temporarily during a stretch of warm days just to tarp it again the next time there's a hard freeze, but it's easiest to just leave it tarped until it is safe. Also if you have snow on top of your tarps, they probably won't heat up much above freezing. I really doubt your bamboos will shoot under the tarps before they would without the tarp.

[canadianplant]

I think the easiest way to tell when you need to uncover it is by getting a cheap weather station, and sticking a sensor under a couple of the tarps which will let you know which should have very accurate readings as long as the device is blocked from sunlight so a sunny day doesn't heat it up. In the last month or so, it has hung between 5-9C with a slight downward trend under one of my tarps so I doubt it will ever drop below freezing as average temperatures should already be on the rise, but since it seems to be holding off the cold extremes, I believe it should also have the ability to hold in the cold by spring, delaying the shooting season while the tarp is still on because warm days don't seem to raise the tarp temperature as much anymore.

I plan on uncovering by around late February for good given that the 15 day forecast looks safe, but in your climate, you can probably leave a tarp on until April if your shoots don't appear until May because they really don't suffer while they are under a tarp especially if you are using transparent ones.

During a heat wave in early spring, I really doubt the tarped bamboo will be warmer than the outdoor temperature from what I have seen so far with my sensor results, but it's not hard to untarp it temporarily during a stretch of warm days just to tarp it again the next time there's a hard freeze, but it's easiest to just leave it tarped until it is safe. Also if you have snow on top of your tarps, they probably won't heat up much above freezing. I really doubt your bamboos will shoot under the tarps before they would without the tarp.

I do know that under the tarp and snow will regulate the temps, not letting it get too hot or too cold.

The first time I uncovered my Rufa, was the end of februrary, when we had a day at 20C, march 1st. Last year I uncovered it about middle of feb, but again, I was an idiot, and didnt cover them when the nights/winds got bad.

I wont think of uncovering it untill the end of february at least. If this eather holds, it may be a bit sooner, if it goes to "normal", it may be a week or 2 longer. What im thinking, is that as long as the day temps are above freezing, and the night temps are around -5C or higher, would be a good guess here.

[stevelau1911]

If you are committed to uncovering it by the end of February and worry about damage, you could always get some greenhouse plastic and build a temporary greenhouse which takes only about 10 minutes. I did it on one of my bamboos for a month back from the beginning of November until late December. I could always do the same thing again in 2-4 weeks, and the moderating effect of a small greenhouse with night time temperatures is huge especially when there are water buckets for a heat sink, and the GH is at a minimal size. Given you are in an even colder zone than me, you could use a large bucket with a fish tank heater, or heating cables in the set up. Here's how mine looked.
http://stevesbamboogarden.blogspot.com/ ... oo-by.html

Unless heating cables are used, I don't think the shooting will be that much earlier since the ground itself seems to take a long time to either cool down or heat up in comparison to the soil in potted plants. I think GH plastic can be bought in any garden center, greenhouse center, online, and PVC pipes are probably the most useful, but I ended up using random materials since it was only a temporary set up.

[canadianplant]

"Commited" is relative I would only do so if the weather permits me to do so. SO far the time is the end of february to the second week of march. ITs just really hard to predict "normal" here , between the months or feb - may, especially the last 10 years. For all I know I wont have a chance untill april!

I have been told to err on the side of caution when using a type of mini greenhouse. There is definitely a chance that it will heat up too fast. I will say that they dont seem to like being exposed for the first few days after a long dark dampish winter.

[stevelau1911]

I sometimes feel the same way about a bamboo being under low light and damp conditions for over 2 months, but I've done it for many species of bamboo already and even with heavier tarping materials that don't let light through, they always turn come out looking exactly the same as they did when they went in the tarp so I don't think getting light is that crucial over winter as long as temperatures remain cool.

One of the options if you desire up to 50% light penetration and complete wind protection is to remove the heavier protection, and use something light such as a frost protection blanket which should be adequate as long as your March temperatures do not drop below zone 6 extremes. Frost blankets are supposed to give 6-8F or protection. It's around 30% cheaper than overwintering film on average and very light and fairly rip proof as long as you don't purposely poke holes in it.

A frost protection blanket seems to be enough to make the difference between minor leaf burn and no leaf burn at all and here's how I use it. This protected leaves from any leaf burn at all on parvifolia at -17C, or 1F, and didn't get blown off when winds exceeded 70mph.

[canadianplant]

I equate uncovering bamboo after winter, like putting indoor plants in the sun right away, without hardening them off/acclimating them. I dont think its that extreme, since they grow outdoors, but I cant imagine the plant enjoying being thrown right into the elements. I could also just be over paranoid lol.

Im going to have to cover them one way or the other. The first time I uncovered my F rufa, after its first winter, march 1st was 20C here. I had no choice but to uncover it!

[needmore]

Why don't you uncover them now while it is still 'chilly' and be prepared to recover them if the forecast gets extreme?

[canadianplant]

Why don't you uncover them now while it is still 'chilly' and be prepared to recover them if the forecast gets extreme?

The risk right now of "extreme" temps is still pretty high. THe low hasnt gone below -10C all week, then this morning was -24C. IF I wait a few weeks, things will start to even out and warm up. I didnt cover them untill the temps dropped below -18C, so they are used to some cold. I figure this is a decent way to let em acclimate a bit to the winter temps.

Im just paranoid cause I killed 2 bamboo last winter/spring, by covering/uncovering wrong. FOr instance, I managed to get Fargesia Scabrida to survive the winter. Instead of putting the tarp flat on the leaves, I left a large air gap, which made it colder then It wouldbve been if it was protected properly. The lower leaves were fine, but I left it exposed duing some cold temps, high windchills and to make it worse, I stupidly planted it in a frost pocket. The same story goes for Pseudosasa Japonica. Most of that was my fault Live and learn.

What is your definition of "chilly"?

[bamboothew]

I'm always worried about "sun-burning" plants that have been shaded for any length of time so I always think it a good idea to put indoor plants out on an overcast day to let them acclimate, and/or partially shade them for a few days. I imagine I'll probably do the same when I untarp my tropicals. Made the mistake last year of sitting a potted multiplex fernleaf on the deck last spring that had been indoors all winter, and less than 2 hours of direct sun burned about 90% of the leaves to a crisp, so I have made a point to be more careful now. That being said, when I first started getting boos I took many phyllostachys out of their shipping boxes and planted them in full sun the same day and never saw one suffer, but they had only shaded for a few days at most so maybe that was the major factor, or maybe phyllos just don't have that issue, not sure.

[Alan_L]

...Instead of putting the tarp flat on the leaves, I left a large air gap, which made it colder then It wouldbve been if it was protected properly.

I don't understand how this could make a difference. If anything the air gap between the leaves and the tarp should have helped, acting as an insulation layer. The leaves that were touching the tarp probably experienced the same temps as outside the temp, although protected from wind.

If I'm wrong about this, please explain it to me!

Why not just open up a flap for now during the warmer periods so the plant gets some colder air, then cover if it gets too cold or too windy? There's no reason you have to have it completely covered then completely uncovered.

[canadianplant]

...Instead of putting the tarp flat on the leaves, I left a large air gap, which made it colder then It wouldbve been if it was protected properly.

I don't understand how this could make a difference. If anything the air gap between the leaves and the tarp should have helped, acting as an insulation layer. The leaves that were touching the tarp probably experienced the same temps as outside the temp, although protected from wind.

If I'm wrong about this, please explain it to me!

Why not just open up a flap for now during the warmer periods so the plant gets some colder air, then cover if it gets too cold or too windy? There's no reason you have to have it completely covered then completely uncovered.

In your areas, I would agree. In my area, we have reliable snow. The snow would be flat against the tarp/leaves/bamboo, and would moderate the temps for the most part. The "air gap" im talking about, was above the snow line, so it let air inside get colder. The parts closest to the top of the leaves were burnt/dead this way, while the flat way (no gap), has been better for me. Ill know better this year for sure.

I would definitely have to be able to cover/uncover it for a few weeks. I am thinking Ill uncover them when the lows dont go below - 10c, and the highs are in the single digits (C). Ill have to keep it covered for a few days, just to make sure, and protect it when it gets cold, or windy. There is a foot of 2 of leaves as mulch/insulation around them both. I wont move any of it untill the end of march - middle of april, temp depending.

I know for a fact that my F rufa wont shoot till may, even with a mild spring. Im unsure when the P Areosulcata shoots here. as mine had to recover some leaves from some top kill.

[Alan_L]

Ah, the tarp was too high and therefore shed the snow -- got it.

[canadianplant]

Ah, the tarp was too high and therefore shed the snow -- got it.

Yeah, I wouldnt suggest protecting your bamboo like that if you get extreme winter temps lol.

I took a look at some of my old threads last night, and realized I uncovered my bamboo in the middle of february! Dumb move on my part! I mustve been really ancy to get things going last year.

[stevelau1911]

Since it didn't take much effort, I took the plastic off my spectabilis and it looks like there is no winter damage. I used a plastic tarp on this one so it did continue to get sun throughout the last 6 weeks it was tarped and I'm finding some of the leaves that were in contact with the plastic look browned which might be from the heating of the plastic since I doubt this species gets leaf damage with zone 7a extremes, but wanted to protect everything this winter just to see how much of an increase in performance I get with shooting season if nothing gets leaf burned aside from my test culms.

I think the cloth based tarps that don't let near 100% light penetration come through are safer as far as protecting even the leaves that come in contact with the tarp.