What does half-hardy perennial be determined? ...
Half-hardy perennials are tender perennials.
They will not survive frost and must be brought indoors during the winter, for example, pelargonium, fuchsia, and heliotrope. Individual microclimates and correct free-draining soil can make an massive difference to their ability to survive the winter. It medium that they are a perennial plant that lives year to year in a heat climate, zone 9 for example, as opposed to an annual which lives to set seed and dies.
It routine they need protection from frost surrounded by Zones 5 & under to come put money on year after year. It those areas, most are dug up & brought indoors. "Tender or half-hardy perennials will survive a mild winter but may not survive a severe winter without protection."
http://www.ces.ncsu.edu/depts/hort/consu...
"Half-hardy Perennial (may not survive if between 10 and 0 degree in winter)"
http://www.geocities.com/legacyherbs/pla...
Here's an illustrate index of half-hardy perennials which includes Begonia, Canna, Lemon Grass, some types of Lobelia & Hollyhock etc:
http://seeds.thompson-morgan.com/uk/en/l...
Hope this is helpful.
Answers: Good question. It's not a true botanical classification but here is an article I read that help to solve the confusion: http://www.hrt.msu.edu/faculty/Runkle/Ju...
Hope this helps.