Tree of 40 Fruit the New York State Agricultural Experiment Station, which was closing due to funding cuts. He began to graft buds from some of the over 250 heritage varieties grown there, some unique, onto a stock tree. Over the course of about five years the tree accumulated branches from forty different "donor" trees, each with a different fruit, including almond, apricot, cherry, nectarine, peach and plum varieties. Each spring the tree's blossom is a mix of different shades of red, pink and white. , Van Aken had produced 16 Trees of 40 Fruit, installed in a variety of private and public locations,
Fruit and Spice Park to stay an active garden club member and develop insights on the different fruits that should be planted until she passed away in 1979. In memory of her and Preston B. Bird, South Date County renamed the Redland Fruit and Spice Park to the Preston B. Bird & Mary Heinlein Fruit and Spice Park in 1980. The park contains more than 500 varieties of fruits, nuts, and spice trees. It also includes more than 80 banana trees, 160 varieties of mango trees, more than 40 varieties of grape trees, and 70 varieties of bamboo trees. It also features guava, jackfruit,