Phyllostachys aureosulcata Alata hardiness.

[needmore]

Not sure how you would define it, we generally start cooling in early October, frosts by mid month, light freezes to follow; November keeps cooling down etc. It is not unusual to have some 10C to 15C days here and there Dec - Feb but not long enough to wake things up. Every winter there are multiple periods of consecutive days with high temps below freezing but still sunshine on some of them. I think the most unusual bamboo aspect of our climate is a very quick warm up in spring. My bamboo seems to shoot early compared to other z6 areas.

[johnw]

Whatever the natural range, temperature limits or whatever variables does information like this below help or hinder the cause of bamboo?

http://www.bambooworld.com/bamboo%20catalogue.htm

Now that is a particularly extreme example, other nurseries are not quite so outrageous in their assertions.

Would it not be better to give an honest Zonal rating for the average gardener so that he/she knows his correctly-chosen plant will stay dependably green throughout a winter - no damage or freezing back?

Of course everyone on this forum is ready to take extraordinary measures to push the limits but that's no reason to call a Z7 plant a Z6 plant. I'd just like to see reliable ratings out there and that has never been the case for bamboo.

The ABS says "Minimum temperature: The minimum temperature is the point at which leaf damage begins to appear after a short exposure to the temperature" - The ABS ratings for Fargeias are not too out of line but Phyllostachys aureosulcata 'Alata' is -5F / -20.55c so we should see no damage whatsoever to date.

[canadianplant]

Well, "honesty" can still be honest with wrong information. Honesty plus informative sellers/buyers is the best way to go IMO. This isnt as easy as it sounds because the amount of conflicting information online, and the fact that there are sellers who are only in it for a buck. Then there are businesses who seem to do both like bamboo world. They seem to take some info from online, but dont mention that the hardiness ratings are more than likely root hardiness, than the temp the canes and leaves can survive (even though they mention the temps are MINIMUM temps, which is a long, long shot on some. The fargesia temp stats arent too far off (most) IMO.

So the question has to be asked now: How can we "properly" determine hardiness ratings for bamboo? Should we use the minimum temps that damage leaves, or should we use the lowest temps that the plant, including roots can survive? Its hard to give a hardiness rating to a plant that can have 10C hardiness difference between leaves, buds culms and roots. Should bamboo be given 2 hardiness ratings - Top kill temps and root hardiness? How can we properly determine the right top kill temp, when there seems to be a 5C margin in which people seem to say (in this case) alata can take?

Zonal ratings are just as skewed. Zone 4 can mean many, many different things. I can be in a zone 7, where my temps drop to the minimum every few years, where as I can be in a zone 7, where the minimums are felts all winter. I could be in a zone 4 with zone 5 or 6 microclimates as well, or a legit zone 4, in a wide open prairie. I could be a zone 3 with no precipitation in winter, which would kill legit zone 3 plants, where as those same plants would survive a zone 3 winter with snow cover. Also, zone 4 in a humid continental climate, could be completely different from zone 4, say, near the coast of the atlantic. To make matters worse, the zone system is flawed, because there are more influences on temp in the city then the maps can actually show.

Lastly, how can we rely on proper information, when taxonomy is so skewed for some species (ie fargesia/borinda/semiarundinaria etc) .

This question also begs to be asked again as well: IF all bamboo in cultivation is similar to fargesia, in the sense that all plants we have are from 1 or 2 specimin that were sent out and propagated, how can we say that XXX is the proper hardiness rating,when there is such a large area in which it is found, and more then likely slight variations in hardiness due to adaptations to that specific site?

[dependable]

It would be difficult to set accurate hardiness ratings for leaf damage based on temperature alone. Seems that wind and dryness would have to be factored in. A half day of dry arctic wind blast in March at 10f seems to do more leaf damage here than half a week at that temp in normal winter conditions.

[johnw]

dependable - No question about those days in March when the sun shines, the snow reflects and ground frozen. But if they can come up with reasonable zone ratings for rhododendrons they can do it for bamboos.

Do I want a rhododendron in the garden that looses its leaves every year? No thank-you. That freezes to the ground? No thank-you. That I can be assured will come back from the roots? Most Z8 and even 9 rhodos will do that; even ponticum which was used as an understock long ago; and while not at all hardy here it does sprout up from down below ocassionally only to freeze back reliably. So with P. aureosulcata what's the harm of saying Z7b but growable in Z6a with the possibility of frequent leaf loss and the rare top loss, it would be truthful and that's what gardeners need.

canadianplant " fargesia, in the sense that all plants we have are from 1 or 2 specimin that were sent out and propagated, how can we say that XXX is the proper hardiness rating,when there is such a large area in which it is found, and more then likely slight variations in hardiness due to adaptations to that specific site?"

We gardeners have to deal with the plants in cultivation, the ones in front of us. Fargesia is not the only genus with but a few representatives in cultivation many rhodo species are in the same boat and still we have to rate them according to the findings of those growing them. Some rhodos in the wild are being re-introduced into cultivation - along with new ones - and they are being tested widely but they are given tentative and sensible ratings on them in advance. Presumably hardier forms too as they collect even higher in the mountains.

[Iowaboo]

My location is between Milwaukee and Chicago, near the Illinois-Wisconsin border, within a few miles of Lake Michigan.

I am growing 4 cultivars of Phyllo. aureosulcata, the plain type form of aureosulcata is the one I've grown the longest, over 30 years, and it is incredibly root hardy. Back before global warming changed my growing zone from 4b to 5b, we had a week where day time highs did not rise above 0F (-18 C) and the coldest night of that sub zero deep freeze was -25 F (-32 C). I had complete top kill of the very young, 2 year old planting. But new shoots sprouted in spring, they did top out shorter than the previous year, but surviving -25 F (-32 C) with minimal mulch is quite a feat.


I also like Phyllostachys atrovaginata for its performance in zone 5. The foliage survives winter in very clean condition. We have not had the cold to truly test this species here, but it seems to be at least as good if not better than aureosulcata for leaf retention over winter.

Thanks for the information, not much information on cold zone bamboo growing for such a long time period as decades. Haven't had luck with atrovaginata as others, and have got it from two places I think, with same results. Decora and humilis were couple other hardy ones that didn't do anything for me for whatever reasons. I've had a couple -20sF winters in the past 5 years to keep things in check.

[canadianplant]

John - So we can at least say we agree that the zone rating system is flawed, especially for bamboo.

So what can be done besides trying to makes sure sellers/buyers are informed? Maybe having a general one zone rating is the problem, since there seems to be such a variation depending on the part of the plant that is damaged. You make a point with rhodies. Now in that case, maybe 2 ratings should be used. One for damage to flower buds, and one for the actual death of the plant (unrecoverable).

But now we get to bamboo. How would we rate it using the above mentioned system? Leaf burn, bud kill, culm death and root death? Would giing a range of 4 temps be too much info or "educating"? Would it be too distracting to say "Phyllostachys areosulcata alata - Leaf hardy to -18C, root hardy to -25C, -30C or lower with deep mulch or snow cover" ?

[foxd]

Personally I feel that Wind Chill makes a better rating system than just Temperature. However I also feel we are going to have a difficult time in pinning down all the variables.

A case in point: Several years ago, two different species of bamboo that were planted right next to each other, experienced a very cold Winter night. Only one was leaf damaged. However, Brad who lives about 9 miles away had both of them leaf damaged and rates them as cold hardy to the same temperature. I haven't a clue as to what the difference is!

Recently I've been wondering if we aren't seeing some sort of epigenetic change in the cold hardiness of some bamboo clones. (I tend to think of this of the mornings as I walk out the front door and see the Sasa veitchii that grows to two different heights from the planting of two different pots. )

[johnw]

But now we get to bamboo. How would we rate it using the above mentioned system? Leaf burn, bud kill, culm death and root death? Would giving a range of 4 temps be too much info or "educating"? Would it be too distracting to say "Phyllostachys areosulcata alata - Leaf hardy to -18C, root hardy to -25C, -30C or lower with deep mulch or snow cover" ?

canadianplant - When you register a rhodo hybrid you must give the plant and bud ratings by temperature tolerance. No rating according to the zone where both foliage and buds are fully hardy are asked for. The problem is twofold, some nurseries will opt for the more optimistic "plant" hardiness zone rather than the "bud" hardiness zone and then not mention bud hardiness at all. Some of this is deception, some is the fact that the plant has not been tested through a typical zone winter - i.e. any rhodo tested here in the last 18 years could hardly be classified as Z6 hardy as we have been having Z7 winters - or should I say Z7 lows, the protracted cold has been Z6 aside from the previous winter. Mix ups as the plants are tested on the west coast and not the east coast and generally not long enough. Funny, hybridizers have a hard time admitting their own babies are ugly or tender.

At best a gardener walks into a garden centre snaps up a Z5 rated rhodo and expects performance without heeding any bud warnings, so the rating had better be accurate for both. Joe Blow can't deal with too much information. We bamboo nuts on the other hand can, so the various temp ratings you suggest for the keeners look reasonable.

Sad after all these many years after introduction we still can't speak definitively about aureo's hardiness up here. For JB I think you need the zone in which you can expect the plant to remain somewhat evergreen w/o looking too tattered by late spring. After an inspection yesterday (low about +1 to 2c) the aureos are looking quite respectable so at this point I'd give it a cold Z7a rating but the winter's not over yet.

There are plenty of rhodos that we can grow here that are impossible all down the eastern seaboard, our cool summers and cool soils make the difference. Thirty-nine years ago we tried nitida here on the coast and found they did better here than in many other milder but hotter areas, then murieliae about 34 years ago - same thing. We have pretty good data for eastern PEI, eastern Newfoundland and most of mainland Nova Scotia for those two species. On the coast we are just now getting a feel for apicirubens (24 years),robusta Campbell (10 years maybe) and dracocephala Rufa (12 years). Only the latter would I recommend unhesitatingly at this point.

Brad certainly has the Phyllos rated objectively and honestly for his area - his rating will be the first I go to until we establish our own. Hopefully we can find that exceptional Phyllo in the sky that will do well here and where you are.

[johnw]

foxd - But wind-chill specifically measures the effect on skin. We can have real wet howlers here in the autumn and the wind-chill will be below zero C. but the plants don't give a hoot. I wonder if it could be adapted to moisture loss in evergreen leaves in general or would each plant require a different formula. It presumably would have to take into account if it is a dry wind as opposed to a moisture-laden wind, day and night to a plant and then there's the sun factor, latitude etc.

[Iowaboo]

I think besides obvious cold temps and wind that I get, lot of sun in winter and frozen ground plays critical role in this boo game for me. I also got an extra treat going into the winter with drought damaged leaves, so even though I've been down to only -7F so far, everything together ganged up on them.

[Mackel in DFW]

What I'd like to add is that a bamboo that is already previously stressed before a really cold onset, will react differently than one that is not. That's why a lot of folks say to make sure your soil is hydrated before a really cold, dry wind.

So not only does genetics come into the calculation when rating hardiness amongst different species, but varying or destabilizing environmental factors within a species such as a poor soil environment, lack of deep roots, lack of an adequate starch buildup, a long previous drought, etc., will alter the effects of a new, added stressor such as very cold temperature.

Synthetic fertilizer probably is not good for cold hardiness either, since you don't have a stable soil milieu if you are chemically altering it cyclically. You might get more rapid growth, but the plant is continually changing it's adaptation abilities because the soil environment keeps changing. It's been stressed. That adaptation ability has been weakened.

This makes the bamboo more likely to experience damage when the manure does hits the fan, figuratively speaking, along with other factors mentioned that have been going on environmentally before the cold onset in the days, weeks, and year before winter. It's like a human who has been jogging all year, eats a fair diet, and another that takes super vitamins instead, when both are exposed to a stressor such as a virus, hunger, cold, etc. the one in good shape will handle it better almost everytime, than the one taking a 1000 percent rda multiviatamin.

I am not convinced that epigenisis in bamboos occurs that rapidly or at all, as evolution is slowwwww, but don't know enough about it with bamboos to really opine on the mater. Mike

[Mackel in DFW]

What stuck in my mind was what Leo S. said, when he mentioned that -25F didn't totally kill, and it wasn't fertilized either. Mike

[stevelau1911]

That's a good way to put it Mike.

Another way to look into a bamboo's hardiness is to compare how hard it is to freeze a small pond vs a very large pond. A very large bamboo grove of the same species will generally take colder temperatures, and more time to have damage than the small one.

Here's the comparison of leaf burn damage of a mature grove of Aureosulcata against my little aureosulcata back in 2010/2011 when it reached between -8F to -9F. Mine still fully leafed back out, but it looked pretty bad as shown here. I wonder if there are multiple cultivators of regular aureosulcata because mine consistently had much weaker cold hardiness to species of similar ratings such as atrovaginata and fargesia rufa.

[canadianplant]

Foxd - Re: epigenesis. Im going to have to do some digging to back this up, but there is someone in colorado, who did that with aloe. The pups eventually becae more hardy with each generation. Mind you I havnt read the article for a while, and didnt look for updated information. Also, its taken about 20 years. IF this is true, then I wouldnt be surprised if this has happened in bamboo to some degree.

Windchill seems to make a difference, but I think its the wind drying out the leaves, rather then the wind being colder=killing them.

John - So the problem is getting reliable data. I wonder if smartphones and QR codes could help here, seeing as now information is literally at hand. I just recently got one, and I can say, Im sick of asking unreliable workers, and having to go home to look stuff up before buying it. Now I can make better informed decisions. Places like this are a great tool as well because we can share information. I probably wouldnt have been crazy enough to try bamboo here without this place to be honest.

Im hoping to get my own data for up here for bamboo starting this year. You mentioned F rufa. That is extremely hardy in my experience. Hardy enough that I may eventually try it unprotected, in the right location.

Mackel - Thats pretty much how I see synthetic fert. However, used properly and not in excess it can make dramatic changes. Mine only get compost and bloodébone meal, plus what ever leaves decompose from winter mulch. They are also planted next to shrubs that fix atmospheric nitrogen, slowly feeding them nitrogen. This year they are getting a good layer of composted manure. It would be interesting if someone could do a controlled fertilized/non fertilized experiment