
Ever since Temple times, Shavuot has been an agriculturally significant festival. Today we perpetuate this aspect of the holiday by bringing "the outdoors in" on Shavuot. Synagogues and homes are decorated with greens, wheat, and flowers.
In Israel, florists enjoy a brisk business, and supermarkets and malls host special promotions on houseplants.
Schoolchildren wear wreaths and help decorate the house with the flowers and leaves they bring from school.
According to legend, when the Torah was given on Mount Sinai, the barren desert exploded with blooming flowers, as if the earth itself rejoiced. This is another reason given for decorating homes and synagogues with greenery.