Re: Hollyhocks and soil





Valerie Lowery@ZEON
05/27/99 02:31 PM

I haven't had much of a problem with hollyhocks, despite our environment.
What the cause must be for the early death is a mystery.  I must disagree
about the importance of humidity in gardening, however.  Here in
Louisville, KY, humidity goes along with our heat in summer (hot, hazy,
humid).  My grey felt-leaved plants (lamb's ear, snow-in-summer, etc) rot
away in mid-summer, sometimes recovering when cooler, less humid temps come
back around in the fall.  Hybrid tea roses are infamous for blackspot here
despite religious showerings of chemicals.  Our local gardening gurus all
talk about the humidity factor, allowing that certain plants are doomed
here because of this stifling atmosphere.  Most plants can take in the
moisture through transpiration.  This is the ideal environment for plants
with a tropical nature, such as orchids and ferns.  In fact, this is the
principle behind foliar feedings.  However, certain plants cannot take the
moisture content that inevitably will bring along fungal growth and some
bacterial attacks.  Look at the susceptibility of monarda and phlox as
examples of what can happen in a humid environment.  Air circulation helps
dry off the leaves, but cannot always effectively carry off all moisture.

Back to hollyhocks.  I often assume that if a plant can survive in my yard
with little care, it can go just about anywhere else and do better.  Under
stressful conditions, and sometimes just because, hollyhocks will succumb
to rust (a fungal infection).  It's called rust because it looks just like
the rust you'll see on metal.  Are the leaves turning yellow and splotchy?
Look on the undersides of the leaves for these rust spots.  I understand
that this is a soil-borne problem (will someone correct me if I'm wrong?).
You may try switching locations for your next batch of plants to see if the
problem persists.  There's probably sprays for it, too.  Another thing is
to try fertilizing it like you would an annual, i.e., about once a month.
Another book I looked at says that they are heavy feeders when blooming.

Good luck!

Val in KY
zone 6a


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