You have to be careful with any design like this because it tends to create a lack of ownership towards the green space. It then becomes the responsibility of someone who doesn't care all that much, a government or landlord usually, and so it's a lawn because that's easy and boring. Creating a sense of public and private ownership of green space is crucial to ensuring that it remains vibrant and well used. This is actually a good use case for an HOA, an organization that can organize and maintain such a space supported by individual homeowners.