Great Plant Sale pre-order Posted on March 19, 2018 Date/Time Date(s) - Monday, Mar 19, 2018 Categories Sales Annuals, perennials and shrubs are available in the pre-order portion of the Great Plant Sale, held by the Buffalo and Erie County Botanical Gardens. The deadline to pre-order is Monday, April. 9. See an article that highlights some of the plants here. See the entire list of plants here.