Tips for this weeks FREEZE

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Ophiuchus
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Tips for this weeks FREEZE

Post by Ophiuchus »

I don't plan to protect my plants and upper teens are anticipated Mon night with mid to low 20's for the whole week beginning tonight.

I plan to keep them watered during the week when the temps move above 32F during the day. Can anyone offer some tips that require little effort on my part that may help them survive?

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Re: Tips for this weeks FREEZE

Post by dependable »

If they are planted in the ground, least effort and perhaps best solution is to leave them be and see how they do. The ones that are not well suited for the climate they are in are unlikely to ever thrive.

If they are in pots, you could put in a shed or tip over and put a tarp on them.

At temperatures below 50*F, there is not a lot of metabolic activity(growth), so you will not need to water much unless very dry. Over watering at lower temperatures can lead to terminal root rot.
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Re: Tips for this weeks FREEZE

Post by Glen »

I would lay potted plants on their sides and cover them with a large tarp. If you layer the plants correctly, you can fit a lot of plants under one large tarp. I think this is the least expensive and easiest way to cover tall potted bamboo plants. I do not know exactly what you are growing, but if you reach the temperatures forecast, you will get significant damage to subtropical clumping bamboos, with the possible exceptions of B. multiplex and B. textilis. When I choose not to protect things, I usually regret it later.

https://www.lowes.com/pd/Blue-Hawk-30-f ... p/50412728
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Re: Tips for this weeks FREEZE

Post by Glen »

dependable wrote:At temperatures below 50*F, there is not a lot of metabolic activity(growth), so you will not need to water much unless very dry. Over watering at lower temperatures can lead to terminal root rot.
When cold and dry winds hit the south, they quickly dry out potted bamboos, which normally experience very high humidity here. While growth certainly does mostly stop in the cold, water use by these plants remains surprisingly high. In my years of growing bamboos down here, I have often had plants damaged from drought in the middle of the winter, because I thought it was cold enough that the plants would not need much water. I always try to soak them right before a hard freeze, and this has never resulted in root rot in my bamboo plants. Of course, the soil will not stay cold here for long. If we had consistently cold temperatures, we might see the problem you describe.
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Re: Tips for this weeks FREEZE

Post by Ophiuchus »

Happy New Year Everyone!!!

The low was 25F, my temp is up to 27F now and should be above 32F in a couple of hours. I will soak pots with water then. They really appear to have dried out and the top layer is frozen and dry to the touch.

Thanks Glen for the tip on the tarp, Tropical Bamboo said the same. I wanted to experiment with this storm while my inventory is still a little small. With 5 days of hard freezes, I should be able to determine what plan I will need to take next year. My plants are cold tolerant 15F-24F, Old Hamii being 24F. I just planted it Feb '17 and have some in 7gal pots.

One of the reasons I didn't want to tip over plants this year is because my 7gal plants have rooted and won't tip over. I nestle the 3gal plants in between until I can establish my nursery further. I still have to bring in dirt, install irrigation and ground cover.
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Re: Tips for this weeks FREEZE

Post by Glen »

I know what you mean about tipping the pots. Once you cut those roots, your watering chores just got more difficult, until you divide the plants.

I think 24 degrees is about right for B. oldhamii. I have seen lower estimates of its cold tolerance. People around here used to quote a figure of 18 degrees. Then, one winter with a low of about 19 degrees topkilled even mature plants. Last winter my B. oldhamii had maybe 30-40% damage with two freezes of 25(windy) and 22 degrees. Those were the only freezes last winter. My 'Hirose', which is probably a form of B. oldhamii, was pretty much topkilled, but it was just planted last spring. I have been told that is is also less cold tolerant than B. oldhamii. Bottom line...I would protect this species (in pots) if I thought it would go below 25 degrees, especially if daytime highs will not be much above freezing.
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Re: Tips for this weeks FREEZE

Post by Ophiuchus »

So I started watering by hand directly into the pots and my hands began to freeze. Ouch...I hooked up the oscillating sprinkler and let it run for 4hrs. Although the temp was in the mid 30's, icicles formed all over the foliage. This happened to me last year and I freaked out.

I was told by Robert Saporito that I had actually insulated the plants by doing so. He said what is really rough on the plants is the wind chill.

Any thoughts?
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Re: Tips for this weeks FREEZE

Post by Ophiuchus »

Glen wrote:I know what you mean about tipping the pots. Once you cut those roots, your watering chores just got more difficult, until you divide the plants.
Glen, I've been pondering the rooting issue once I put down the ground cover. I'm assuming the roots will go through it and once I attempt to move it, the roots will damage the ground cover.

I was thinking about building pvc racks for stability (tipping) and elevation above the ground cover.

Any thoughts? Anyone?
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Re: Tips for this weeks FREEZE

Post by Ophiuchus »

dependable wrote:If they are planted in the ground, least effort and perhaps best solution is to leave them be and see how they do. The ones that are not well suited for the climate they are in are unlikely to ever thrive.
Agreed, I only added mulch to the in ground plants. I should get a good idea what species I have that is not suited to my climate this year. Brrr...I can't imagine the temps you're dealing with.

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Re: Tips for this weeks FREEZE

Post by Glen »

Ophiuchus wrote:So I started watering by hand directly into the pots and my hands began to freeze. Ouch...I hooked up the oscillating sprinkler and let it run for 4hrs. Although the temp was in the mid 30's, icicles formed all over the foliage. This happened to me last year and I freaked out.

I was told by Robert Saporito that I had actually insulated the plants by doing so. He said what is really rough on the plants is the wind chill.

Any thoughts?
I was out doing the same thing today. I was a little warmer here, so no icicles yet!

Spraying plants with water during a freeze is often used by citrus growers, and it does protect the plants from damage. HOWEVER, this only works if the plants are sprayed with liquid water continuously until temperatures have warmed. As the water freezes, it releases a little heat, which prevents the temperature of the plant from plummeting. This would not work well with bamboos, in most cases, because the ice buildup will destroy the plants by smashing them. If you have grown bamboos through an ice storm, you know what I mean. The ice itself is not going to provide much protection, as it is not a great insulator. (Snow would, but that is a whole other issue.)

When I water before cold weather, I try to water while the foliage still has time to dry before the freeze, or I water without spraying the foliage. I just use this as a general guideline with all my plants. Some plants, like certain palms, seem to dislike water on their foliage or in their crowns during a freeze, but I have seen no evidence that this applies to bamboos. I do not think the ice from your irrigation will cause any damage to your bamboos, unless it got heavy enough to break them. Keeping their roots moist during windy weather is important.

A discussion of the effects of wind on plants during cold weather is very complicated, and full of misinformation. Briefly, without wind, radiational cooling will allow anything exposed to the sky to get colder than the air. When this happens, the upper part of bamboo clumps can be damaged, but the plants can protect their own bases by providing a thermal blanket. Also, any plants under evergreen trees get a benefit. With wind, the effects of any overhead thermal blanket are minimized, so everything will reach about the same temperature. However, it also means that there will not be any areas that crash to extreme lows, because the air stays mixed. Windchill is concerned mainly with the rate of heat loss, so this is not really a measure of much use when talking about plants. They care mostly about the ACTUAL temperature. There probably are very specific cases where the rate of heat loss does play an important role for certain plants, such as a thick trunked palm during a short duration freeze. (Again, that is another discussion.) What I am saying is that temperature and wind speed can interact in different ways, and whether wind is good or bad really depends on so many factors that it is hard to generalize. I will say that wind definitely can tatter and fray foliage in the winter. This will quickly be replaced when the weather warms, as the buds are not normally damaged.

While discussing bamboos and cold damage, I have often heard it said that wind is worse than the actual cold temperature. My personal position is that I do not have enough information to draw a conclusion, but I tend to think that the wind damage is mostly cosmetic, and the real damage to culms, branches, and buds is caused primarily by the actual low temperature. Let me note that I am not talking about any bamboos grown in areas where the ground freezes. I am fortunately quite ignorant of the complexities of growing bamboos under those conditions :D .
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Re: Tips for this weeks FREEZE

Post by Glen »

Ophiuchus wrote:
Glen wrote:I know what you mean about tipping the pots. Once you cut those roots, your watering chores just got more difficult, until you divide the plants.
Glen, I've been pondering the rooting issue once I put down the ground cover. I'm assuming the roots will go through it and once I attempt to move it, the roots will damage the ground cover.

I was thinking about building pvc racks for stability (tipping) and elevation above the ground cover.

Any thoughts? Anyone?
Bamboo roots will go through cheap consumer grade landscape fabric like it is not even there, creating a complete mess. I have not ever used a commercial grade fabric, but it should work much better, and that is what the larger producers seem to use. I have never asked anyone about how they manage this.

The other way to control rooting is to periodically lift the pots, breaking roots before they get too well established. This will be a lot of work if you have a large inventory, and will not work well if you have very large pots. It would also not be good for your back.

I intentionally let my plants root into the ground, because it reduces my need to water, end mostly eliminates the potential disaster of accidentally letting plants dry past the wilting point, which can set growth back significantly. This may not be a good idea for sale plants. If you sell a plant during the warm season, right after cutting its roots, the customer may have a hard time preventing it from getting too dry. If I need to cut a plant loose during warm weather, I try to give it a lot of attention for a couple weeks, so it can regenerate lost roots.

As for elevating the pots, I have not thought about this, or seen it done. What do you have in mind?

Concerning stabilization...for a commercial operation, I would put strong posts in the ground (with concrete), and suspend metal pipes horizontally (something like EMT Conduit, or galvanized chain-link fence pipe). A row of tall bamboos in a strong wind has a lot of leverage, and you need something that will not break. PVC gets brittle after a few years, and is not terribly strong in an application like this. Treated wooden posts and galvanized pipe will last, and be strong enough, barring a tornado or a strong hurricane. Place the horizontal bars as high as is practical, if you plan to have tall specimens, and make sure they are perpendicular to your most common wind directions. In your case, as in mine, the bars should be placed east-west.
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Re: Tips for this weeks FREEZE

Post by Ophiuchus »

Thanks for all the info Glen. You're right, watering foliage without time to dry out is a bad idea. The weight of the ice bends culms over and my leaves are burned/curled. I appreciate you reminding me that new leaves emerge quickly as they did last year when I did this. My heart sank as I looked at my poor babies this morning.

Lesson learned here for next year, only water foliage with time to completely dry out before freeze or water pots only. Temp got down to 20F and the pots still look dried out. My damage is done, so I'm going to water the foliage again to remove ice and shut off asap to give time to dry before temps drop again.
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Re: Tips for this weeks FREEZE

Post by Ophiuchus »

My sprinkler died and I had to run up to Home Depot to get a new one with 4000Sq Ft coverage. Plants already look better, but still damaged. I do believe with the water I've drenched them with has made them looked better.

I'm gonna cut off the water after 2hrs of watering. This should give them time to dry before freezing.

Yikes....I hope I haven't frozen my plants.
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Re: Tips for this weeks FREEZE

Post by Glen »

I do not think anything you did caused harm. It is certainly tough watching these subtropical plants face our "less tropical than we would like climate".

I watered and protected things yesterday, so now it is just time to wait and see what happens. I am supposed to get to the low 20's tonight, so wish me luck!
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Re: Tips for this weeks FREEZE

Post by Ophiuchus »

Glen wrote:I do not think anything you did caused harm. It is certainly tough watching these subtropical plants face our "less tropical than we would like climate".

I watered and protected things yesterday, so now it is just time to wait and see what happens. I am supposed to get to the low 20's tonight, so wish me luck!
Good morning, I hope your plants weathered well. I have leaf burn on all my plants, in ground and in pots. With the exception of Fernleaf and Chinese Goddess that are in 3gal pots. Burned leaf species include Graceful, Emerald, Kanapaha, Asian Lemon, Blue Chugii, Old Hamii and Contracta.

I haven't notice too much top kill yet on in ground plants, how long does it take to die off? I've got my fingers crossed new leaves will emerge after this brutal storm.

Can you still divide culms that have been top killed?
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