With a desire to show the community the beauty of a nature-inspired water-wise garden, the Vallecitos Water District donated a California native plant garden to Heritage Park located within Walnut Grove Park. Installed in one day by hundreds of volunteers back in 2008, the garden was a collaborative effort among the Vallecitos Water District, the City of San Marcos, and several other local organizations. Local native plant expert Greg Rubin designed it to feature two key components: a Victorian formal garden, which shows how native plants can be used in a formal setting, and an ethnobotanical garden that demonstrates the cultural uses of plants by the Native Americans that used to live in the area. Both plant components beautify the park and provide an outstanding example of a drought-friendly landscape. The garden can be viewed during normal park hours.
In 2012, Vallecitos partnered with the San Marcos Historical Society to offer education programs at Heritage Park by giving visiting elementary students a hands on demonstration and presentation about how residents obtained water and disposed of their wastewater 100 years ago. This is featured during the park's “Hands on History” program. The native plant garden is also highlighted. Vallecitos pays for the student’s school bus transportation to the park to increase participation.