Question
I live in Colorado.  I purchased beautiful verbena hanging baskets in May.  They
were beautiful!  Now they look terrible.  I try to water them every day,  I have
tried to let them dry out in between watering.  They get morning sun and that is
it.  I did dead head them.  They look very dry and bad if I lift the top layer of the
leaves.  Any ideas?  Is there hope?

Answer
Are the leaves dry and crispy?  As is the case with Roses, Powdery Mildew is one of those Verbena diseases where you don't ask 'if' your Verbena will get it, you ask 'when'.  It is so common that Powdery Mildew resistant varieties are now introduced.  Full Sun inhibits disease development; limited sun, as seems to be the case here, promotes it.

Of course it could also be something else.  Any gray or brown mold there or on the soil?  How do the roots look?  Could be a Fungus problem, Botrytis, Pythium Root Rot -- which shows up as dark brown roots, plants wilt and turn Yellow.  But most of the time, it is Powdery Mildew.

Recovery of your Verbenas depends on how much work and resources you want to put into curing them.

Re-pot everything and discard the old soil, keeping the rootballs as intact as possible.  Mix your own soil -- Peat Moss plus Humus plus Sand.  As you transplant, dip the plant, stems and leaves, into a homemade Fungicide.  Make a solution of 1 tsp dishwashing liquid plus 1/4 cup baking soda plus 1 gal water, then mix well and dip Verbenas.  Put them in the Sun to dry.

Then WATER with Messenger harpin protein.  This will accelerate and improve healing in injured plants, then it will help them grow and replace damaged leaves.  You can spray this later, but right now it has to get into the roots and stems with no interference from your Mildew fungicide.

IF YOU CAN, and ONLY if you can, if there are sprouting leaves on any of the stems, cut the stem down to those sprouting leaves.

Lots of work, depends on how much liked them.  I would!

How's the humidity and temperature going?