Agave victoria-reginae Bustamonte Form

Agave victoria-reginae Bustamonte, MX form has shown to be one of the more cold hardy forms. Plants have taken -11F and continue to be the best performer in the garden. Plants need radicle drainage in the garden for winter. During the summer month plants are quite tolerant of moisture and can really grow once they have the root space. 
 
I do not guarantee these in a zone 5/6 because everyones growing conditions are different but this would be a good trial plant to grow in your cold outdoor garden. Try to plant outdoor 90 days before 1st hard freeze.