The packing shed and loading dock Weston, MA, in the 1930s. The building was moved to Hopkinton and used for bareroot storage and potting facility.

During the early 40s Peter's niece Lucy, a schoolteacher in Latvia, came to visit. During her stay World War II broke out and she was forced to remain; she enjoyed working with her family and the plants, and thus initiated her career at Weston Nurseries. As the nursery expanded, Anna became more involved in office work, and passed along her knowledge of growing perennials to Lucy, who was in charge of that department until her retirement in 1990. After the war, other displaced Latvian immigrants, professional and unskilled alike, came to work for the Mezitts.

Urban development began encroaching on the nursery. In 1944, realizing that their operations in Weston were being limited by many factors outside their control, the family began to look for new land. They had observed that on hillside locations on the Weston land late spring and early fall frosts were avoided, providing micro-climates that allowed a greater variety of plants to grow.

Peter and Ed found the land they were looking for in about 300 acres of hilly, rough and rocky abandoned farmland in Hopkinton. This site offered a unique opportunity to markedly extend the growing season and produce crops similar to those in more southern regions. But the boulders and rough, hilly terrain proved to be an immediate challenge. With the help of the U.S. Soil Conservation Service, terraces were built to control water run off. Contour planting was initiated, and many miles of drainage tiles were installed to drain the heavy hardpan subsoil.

Roads were built, irrigation ponds were dug and stones and boulders grubbed out to carve out areas to grow crops. The staff began the task of moving the entire nursery to Hopkinton, while operations in Weston continued.

They cleared land and built roads. As fields were prepared, plants were moved to the new site. World War II forced nursery production to switch for several years to growing food crops in both locations. During this time, moving the nursery continued. Greenhouses and buildings were taken down and reconstructed in Hopkinton and new facilities were designed and built.