I have read that some plants get root rots and fungus diseases in the
combination of warm soil and water, but not in cool soil and water. For
instance rhododendrons sometimes get root rot with that combination of warm
soil and water whereas they seem to be able to take tremendous amounts of
moistness when the weather is cool. Perhaps the calibrachoa like the cool
rainy weather, but are more prone to root rot when the weather is warmer? In
that case, I might let them dry out a bit more between waterings and see if
that makes a difference.
"Patty Winter" wrote in message
...
I'm in the San Francisco Bay Area, not too far from the bay
itself, so a very moderate climate. A few months ago, I planted
some "Trailing Blue" and "Terra Cotta" calibrachoa in front of
my house as a groundcover. (The front faces due east.)

All was well until two or three weeks ago. The plants *loved*
the late rains we got in May, tripling in growth within a few
weeks. But now some of the Terra Cotta ones (only those; not
the other variety) are wilting and dying. I've been watering
them regularly; even daily or twice a day during a couple of
recent heat spells. When I removed one of the smaller plants
today (figuring that I could put it in a pot and keep a closer
eye on it), the soil was nice and wet. I don't think I'm
overwatering them; as I mentioned, they loved it when they got
more water than this in cooler weather.

Other than the leaves and flowers curling up, I've seen no
external signs of trouble. I.e., no snail bites, no insects,
no discoloration of the leaves.

My current plan is to replant the Terra Cotta ones in the
fall so that they'll be more established by next summer. But
unless I can be sure what the problem is, it might just happen
again. For example, are the watering needs of the two varieties
any different? The Proven Winners tags for both types say "Moist,
well-drained soil." (The natural soil here is adobe, but that
garden area has been well amended.) I'd appreciate any thoughts
anyone might have on this perplexing problem.


Thanks!

Patty