Question
We just purchased Plumbago bushes in New Jersey to plant in our Yardley, Pa  
garden.  We are confused by the information on whether or not  they will
survive cold winters.  It seems they are a tropical plant.  These ARE NOT
ground cover plants, but the full grown bushes with bright blue five-petal
flowers.  The tag says they will grow 4 to 6 ft. tall.  We will return them if you
say they won't survive. Thank you so much.  Richard.

Answer
Hi Richard,
Check out the link below.  It has some images of the Cape Plumbago, Plumbago auriculata.

http://www.floridata.com/ref/P/plumbago.cfm

If this is your plant, it is not hard in Pennsylvania.  It is only hardy to Zone 8B which would be in the Gulf South and Southern Arizona, South Texas, etc.  It is originally from South Africa.

I hope this helps.
Tom