Distressed by the lack of trees in the area, he first tried unsuccessfully to transplant young trees from nearby coulees. He obtained his first seedling spruce from Woodstock, Ontario, in 1913 and they thrived. He became so enthused with spruce that by 1918 he had thousands of them. He also planted acres of peonies. These provided a splash of color on what was formerly open prairie.

He became interested in developing new varieties of tree fruits, mostly apples, crabapples, pears and plums. He was so successful that two of his apples and two of his crabapples are listed in the North American Register of Fruit and Nut Varieties. They are the Heyer 8 and Heyer 7 crabapples and the Heyer 12 and Heyer 20 apples, all introduced between 1938 and 1940. Horticulture became such a passion with Heyer that he seeded down a large part of his farm to grass and turned the rest over to his brother to farm. This left Heyer free to plant and care for more trees and peonies.

Heyer, who never married, recognized the need for ensuring his tree fruit would be of practical use in prairie kitchens. He took time for canning, preserving and jelly-making.

He was an inspiration to farm families across the west. Some of the techniques he developed for tree-growing contributed to the establishment of hundreds of farm shelterbelts. HIS tree fruits are widely grown in farm and city gardens. His hardy seedstock is still used in development of new varieties.

Adolph Heyerís contributions to horticulture were recognized in 1949 when he was awarded an honorary life membership in the Saskatchewan Horticultural Society.