Re: Frost/freeze tolerance
- Subject: Re: Frost/freeze tolerance
- From: p*@mindspring.com
- Date: Tue, 10 Apr 2007 01:09:31 -0400 (EDT)
- List-archive: <http://www.hort.net/lists/iris/> (Web Archive)
Yes, you are correct it would be difficult to determine damage of a stalk and or its buds before it has emerged from a fan. I think that might be a completely different characteristic factor to consider and would have to be observed over the next couple of weeks after a freeze/frost. I did have some freeze in the fan as well. Considering how cold it got for you Betty I wouldn't expect much to survive and you would have a very short list of clumps to report on. However, if something does bloom over the next... say three weeks you can be pretty sure it survived the freeze and assess its damage at that time. If a stalk emerges undamaged after that it wasn't formed enough to be affected or there could be some tolerance if earlier stalks showed damage.
Yes, I agree that all of that is frost/freeze damage and would have to be assessed in the weeks after the potential damage occurred. I have simply assessed for myself (and as an example) from the onset of potential damage what particular clumps to look into further thjat don't appear to be damaged. All of the unmentioned others have significant damage and it will be even more obvious in time. If a clump "decides" to send up later stalks which are strictly still in season (not rebloom) and there are obvious fans that aborted or froze that would be considered some earlier freezing tolerance as above. Pollen sterility is significant damage, but irrelevant to the gardener/landscaper simply wanting it to bloom dependably.
So, we could hold off reporting all data until the end of the regular bloom season when all observations can be completely evaluated. Observations and dates recorded for freezing and bloom time of predetermined clumps once a freeze has occurred. If there hasn't been a freeze of concern to occcur, no data need be taken. So it wouldn't require one to go out and see what has started and at what stage a clump is at. We wait until it happens and then observe.
I will note that only established clumps should be evaluated for data, not first year seedlings or plants with only one or two fans with bloom potential.
I think a Master List to check off would be too long as there are just too many cultivars. Many of us know how long the AIS Symposium Ballot is. Now imagine that for all the varieties out in the trade. Each person need only make a list of their own varieties or a copy of their garden layout and make notes on it. I had included a few of my undamaged seedlings in my list so that we might see if there is a trend/ability of some cultivars contributing freeze tolerance to offspring. If you see something in your seedlings note the parent(s).
In total I had a total of seven plants so far observeably undamaged and at a low 27 F. If it gets colder where you are you obviously would most likely be observing more damage and have less to report on.
Paul Archer
Raleigh, NC
>
>I can not determine damage immediately.
>
>Some of the stalks will have melted and fallen over. These are easy.
>
>Past experience with frozen stalks tells me that stalks can look fine upon
>examination, but exhibit a multitude of problems as the season advances.
>Extreme situation for these seemingly unaffected stalks being empty or blasted
>spaths. No buds. Other, less dramatic results are variable and include lack
>of pollen. This is still freeze damage.
>
>How can one look at a clump of irises and determine, visually, if the stalks
>were zapped before they ever emerged above the foliage? Careful observation
>as time passes can determine fans, containing stalks, which have rotted off
>at the rhizome. This is one way to determine rebloom in a cultivar that was
>not able to extend early in the fall. With luck they will simply peel off
>during some later clean up without rot.
>
>Not counting seedlings, I grow approximately 600 cultivars. Give or take a
>hundred or so. Many in multiple spots. I would need to know which varieties
>were showing stalks at the time of the freeze. Then I would need to know if
>they continued to grow or simply rotted in place. Will the cultivar put up
>later stalks? Some do in normal seasons while some never do.
>
>If an established clump wasn't showing stalks before the freeze, but doesn't
>bloom, can one say that it was frozen out? Or did it just decide to take a
>year off?
>
>Glancing across the garden, the day before the first night of the freeze, I
>would have said about 50% of my irises were already showing stalks. I was on
>a fast track to an accelerated season where most everything bloomed
>together.
>
>I visualize a master list with boxes to check.
>
>I've lost bloom stalks before but not on this scale. I've never lost
>freshly germinated seedlings before.
>
>
>________________________________________________________
>Betty W. in South-central KY Zone 6 ---If you don't cross them, you can't
>plant them!
>Bridge In Time Iris Garden@website:
>Where the seeds are in the pots once again!
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