This image is of a working farm that raises tulips, owned by the Veldheer family. The Veldheer tulip farm now produces over 5 million bulbs each year.
The description states:
Veldheer’s Tulip Gardens, four miles north on U.S. 31. The development of a tulip bulb into a flowering size Tulip takes several years of careful planting and cultivation. Visitors enjoy the many colorful varieties which bloom here in May.
–The postcard dates from the 1960s.