Posted: 05/08/2012 at 18:14
An annual will flower and set seed in the first year-half hardy denotes not frost tolerant, hardy frost tolerant
A biennial will take one year from sowing to flower to set seed -it is usually hardy
A perennial will flower year after year after year-however some are short-lived some are tender,some not.
It is not easy or straightforward-just comes with knowledge and time-I would continue to read the labels or look it up if you are not sure.