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Re: H. 'Liberty', will the edge deteriorate?

  • Subject: Re: H. 'Liberty', will the edge deteriorate?
  • From: "Bill Meyer" <njhosta@hotmail.com>
  • Date: Sun, 17 Oct 2004 23:51:56 -0400

Hi Ray,
       I think there's a point where a specific hosta will cut off white
tissue. While environmental factors may speed that time, each cultivar will
have a different point. Some don't seem to shed the white tissue at all
during the main season. Others tend to keep it until very late in the
season, while some start letting it die in June. I don't think how wide it
is causes it to be shed any sooner or later for the most part. Maybe a plant
with a lot of white that is under a lot of stress might shed it sooner just
because of the difficulty in keeping it going.
       When I say "shed" I mean that it is the same as shedding an all-white
division. The plant just cuts off the flow to that part. It may be the same
mechanism as the plant uses for shedding its top growth when it goes into
dormancy. With the water from the roots cut off, the tissue dies and we have
"melting out".By now many of us have seen how all-white divisions just melt
away whether in shade or sun.
       It may just be that plants that have more white tissue look a lot
worse when they melt out. It's a lot more noticeable on them than it is on
one with a very narrow white margin since so much of the leaf disappears.
Jim Anderson calls the white tissue "parasitic" because the rhizome and
roots supply it with water and it gives nothing back because it can't
photosynthesize. There is no reason for the plant to keep it, other than the
possibility of diseases entering the plant when it allows part of the leaves
to decay in contact with the healthy part.
       With tearing, cupping, or other deformities, it's something
different. Usually that has to do with the leaf structure. Most deformities
result from two different tissues that grow at different rates or have
different thicknesses or things like that. These things often change when
the color changes in a sport, so the variegated ones show it most of the
time but green or gold tissues also do this. It isn't just the white tissues
that deform on chimeras (plants with two different tissues). What type of
deformity is determined by leaf thickness, growth rate (how far apart the
veins are), vein strength and rigidity, resistance to tearing, and things
like that. In other words it's a predictable, mechanical process. Thin leaf
material + strong rigid veins + faster growing tissue in the margin =
piecrusting. Thick leaf material + flexible veins + slower growing margin
tissue = cupping. That sort of thing.
                                              .............Bill Meyer

> Bill, thanks for your comments, they are always appreciated.
> I'm struggling with your statement that "there's probably no relevance to
> wide the margin is."  Seems to me that the more white, the more problems,
> whether it be center or edge variegation.
> My perception is the narrower the white center, the less severe of a
> melting out will be. If accurate, wouldn't the same hold true for white
> the wider the edge, the more prone to melting, tearing and/or cupping?
> Do the different leaf layers (L1 vs.L2) have any bearing on this subject?
> Not arguing, just trying to learn.
> Ray Rodgers, Bartonville, IL, Zone 5
> In a message dated 10/14/2004 10:12:32 PM Central Standard Time,
> njhosta@hotmail.com writes:
> "Melting Out" is really
> the plant shedding unnecessary nonfunctioning tissue and has nothing to do
> with the sun or anything else. Insufficient water may cause the plant to
> rid of it sooner, but most other environmental factors don't seem to be
> involved. Possibly certain soil elements might be a factor, but nobody
> at this time.
>         Now that we have that, there's no probably no relevance to how
> the margin is. The amount of stress on a plant can hasten it's "decision"
> stop supplying water from the roots to white tissue, but it's probably a
> genetic thing how long a given cultivar will hold it.
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