Answer: You will be able to locate your zone and find some information about what the zones mean here: http://www.ars-grin.gov/ars/Beltsville/na/hardzone/ushzmap.h... Your county extension (431-7260) should also be able to help you determine which plants or varieties do best in your local soil and climate.
If you try the "tried and true" favorite flowers which are rated for zones 3 to 8 and then plant them according to their lighting preferences, you should be just fine. However, in many cases the difference between success and failure is directly related to soil preparation more than anything else.
You might want to take a look at a book or two about gardening and see what is being recommended. I particularly like the books in the Dummies series because they are straightforward and include clear how to instructions about things like site/microclimate analysis, soil testing and preparation, planting area preparation including how to inprove your soil, plant selection, planting instructions, then follow-up care and maintenance. There are books specifically on roses (ie "Roses for Dummies"), on perennials, and on annuals you might find helpful.
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