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13-09-2004, 07:37 AM

In article ,
(Fleemo) wrote:

Kinda looks like it is coated with powdery mildew, though I've never seen
it get THAT bad. If that's not a powdery coating then it's not powdery
mildew. But if that IS what it is, it won't necessarily kill the clump if
it was otherwise going to perennialize. But you'll have to clip the
infected plant to the ground, discard rather than compost the infected
leaves, clean up the area super-well, trim back surrounding plants to
permit better air circulation & better sun exposure, & water from the
ground rather than with overhead sprinklers. Spray any autumn regrowth
with dilute milk to keep the powdery mildew at bay, & in spring when the
clump returns in earnest, give it another milky spraying, which works far
better than do chemical fungicides on powdery mildew.

Thanks Paghat! Looking around my garden, it would appear that I have
more of this stuff on my boston ivy. Where does this stuff come from
and how is it spread from place to place in my garden? Is there any
way to eradicate it once and for all?

-Fleemo

Powdery mildew likes especially perennials & deciduous shrubs & vines,
though it's not totally adverse to certain evergreens, such as euonymous.
It gets started best where air circulation is poor & plants are watered
from overhead, where plants are too shaded or crowded, or generally
stressed in imperfect conditions. Mildew spoors are all around us all the
time. They tend to take hold on plants that are for some reason stressed,
or which are notably susceptible, like phloxes & beebalms.

Clipping & pruning for better circulation & to remove infected leaves, &
watering the ground only, is often all it takes to control it. If it only
gets to plants in autumn it may only mean cutting things back that were
going to drop leaves or die back soon anyway. If it only reaches the lower
leaves of a deciduous shrub late in autumn, it's not worth worrying about,
except to clean up the fallen leaves in order to dispose of the spoors.

Fallen leaves & clippings should be discarded, not composted or kept for
sake of leafmold, as the spoors are harbored in leaf particles & end up in
the soil through winter until time to start up again on the plant the
following year. Neem or other horticulatural oil can be sprayed on the
ground around infected plants, as that will bind the mildew spores to the
soil. New spring foliage can be sprayed with dilute milk which keeps the
mildew from getting restarted.

-paghat the ratgirl

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
Visit the Garden of Paghat the Ratgirl: http://www.paghat.com