The important thing to remember when building out your website is that you can't be all things to all people. Visitors to the Internet looking for specific plant information are going to use a search engine like Google, Yahoo, or Ask. So resist the urge to cram as much information on the page as you can.
You should list the plant categories:
Annuals - usually planted in the spring and are replanted each year
Perennials - depending upon your growing zone they will return each year
Flowering Shrubs - we carry both decidious and evergreen
Trees - we carry flowering, shade trees and evergreens
Aquatic Plants - we offer hardy and tropical varieties of flowering waterlily
Holiday Plants - we carry plants for holidays from Valentine's Day to Christmas!