Question
In the center of a 5/8 flower garden I planted Pampus Grass and was happy with it here in Rhode Island. My questions are; Here in zone 5 is this plant considered a PERENNIAL, or an ANNUAL? Also, even though it grew to about 5 1/2 feet tall, it had no plumes. Did I do something wrong?

Answer
Pampas grass are definitely considered marginal for Zone 5.  I do the plant ordering for our large retail plant nursery.  And through numerous distributors, I have only been able to find one variety of pampas grass that was considered cold hardy for Zone 5 : Cortaderia selloana 'Pumila' dwarf pampas grass, cold hardy Z5.  So most likely you don't have that variety.  All other pampas grass would be considered cold hardy to Zone 6.  One Zone warmer then yours.  So it might not make it through the winter.  And some books say Zone 5/6 which definitely makes it marginal.  To make it withstand the winter cold better, do not cut it back until Spring.  This will help protect the crown and mulch around it with a think layer of Hay.  Did you fertilize it this year?  If it makes it through the winter you should use Osmocote, a slow release fertilizer, by sprinkling the granules around the base of the plant and work it into the top few inches of the soil.  It probably didn't bloom this year, because it takes a few years for them to get established and then bloom.  But using Osmocote should help it.  Also next Fall use a B1 or SuperThrive, to help establish a healthy deep root system so that it can become more cold hardy as the roots get into deeper soil.   I hope this helps, let me know if you have any other questions.