I wouldn’t call grass a garden. The horticulture surrounds what is now grass and what will become paving suitable for entertainment and high heels. I love that Trump is personally interested. “He admires the bucolic vista from the veranda off the Oval Office and has taken a keen interest in the groundskeeping work of the National Park Service.”
I would call grass surrounded by flowers and other plantings a garden. I would call a paved courtyard with plantings around it a courtyard with plantings.