[AZ] Re: frosty green crystal-like substance on my azaleas
- The lichen just considers the azalea to be a platform such as a rock
or tree is a platform. It doesn't always reflect on the health of the
platform if it is an azalea or other plant.
Lichens indicate an older plant since they are slow growers, but an
azalea that has lichens growing on it has an open structure that gets
air and light. Lichens grow in open sunny situations. On a plant
that is normally open, that is OK. On a plant that should have denser
growth when healthy, that is an indication that it is not healthy.
Three types of lichens have been described: (1) crustose forms, which
are flattened against the limb; (2) folicose forms, which produce
leaflike folds above the limb; and (3) fruiticose lichens, which
produce highly branched structures with hair or fingerlike
projections. Folicose and fruiticose lichens on leaves may shade
foliage, but shading may slow as the host plant grows. A thick
covering of lichens on a twig or branch may interfere with gas
exchange of host tissues, causing decline or death.
I have a slight disagreement Mike. Many azaleas thrive on older wood.
Mine are mostly over 40 years old and just have older wood. They
seem to maintain their vigor just fine. I don't have many natives
like you do.
--- In email@example.com, Mike Creel <mikeacreel@...> wrote:
> Nancy, I have photographed lichens on rocks and trees for years,
enjoying their beauty. On shrubs like azaleas I think lichens are a
sign that the plant's above ground stems are growing old, losing
vitality and nearing the the end of their life cycle. In other words
your azaleas are more in need of pruning than they are any kind of
poison to kill the lichens. Old stems, too old, are much more likely
to be populated by lichens than younger, more vigorous stems. Some
times too much spray irrigation can encourage lichens.
> Azaleas are shrubs, and their upright stems are not permanent like
the trunk of a tree. In nature the upright stems grow for perhaps 15
years, sometimes more or less, and then die, causing the plant to
regenerate from the root and grow new upright stems. In gardens an
azalea should be pruned periodically, removing obviously old stems and
causing the plant to regenerate from the base.
> In Maryland with winter approaching, it is probably too late to do
growing season pruning to encourage new growth this season. But
pruning an azalea during the dormant season (late fall, winter, early
spring) by one third to one half could cause much new growth in the
spring. I am sure other members of our group will have opinions on
this winter pruning.
> Mike Creel, SC
> --- On Sat, 8/30/08, William C. Miller III <bill@...> wrote:
> From: William C. Miller III <bill@...>
> Subject: Re: [AZ] Re: frosty green crystal-like substance on my azaleas
> To: firstname.lastname@example.org, bnbled@...
> Date: Saturday, August 30, 2008, 4:35 PM
> Hi Nancy,
> I don't know about "crystal-like, " but I suspect you have lichen.
Lichens are the result of a symbiotic relationship between a fungus
and an algae. It isn't especially attractive, but it probably doesn't
harm the azaleas.
> See the image at:
> http://www.pbase com/azaleasociet y/image/82092061
> One suggestion in the literature is to spray with a copper sulfate
solution. I don't know if that works --- or if it's a good idea,
since I've never had to deal with lichens. For information along this
line, see the Web site at: http://www.gardenop us.com/Lichen. htm
> William C. Miller III
> Bethesda, Maryland
> www.theazaleaworks. com
> bnbled wrote:
> --- In azaleas@yahoogroups .com, Nancyrsomers@ ... wrote:
> > [this is from the ASK US page, so please send me a CC]
> > Hi I live in Somers CT and my azaleas have some type of a fungus -
> it is a
> > spiky light green on the bark and it is on all of my plants - one
> is relatively
> > new - They are planted near the house and mostly get early to late
> > sun -
> > Have you ever seen this? It is worse this year and I am noticing
> that there
> > are essentially no buds on my plants -!
> > Can you help?
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