Maybe a better question is to ask what "experiences" the garden because there is a huge presence life on the ground and just below the surface.
When I first started to design this garden I had little idea of where it would go. Vaguely aware of changing light over the course of a day, I had barely an inkling that the light could change over the course of a year, or that trees growing nearby would decrease the light over time, or even that the things I planted myself would change the light, heat, and water distribution in the garden.
Over the years squirrels and other animals have distributed things, randomly or not, in a way I couldn't have predicted. And spreading plants, airborne seeds, and new additions have changed the garden's composition.
As things change at the surface they have also changed in the soil. So new fungi, new microbes, and new invertebrates have become established. The garden plot is the same as when I started. It's the same dimension in terms of square feet. But the dimensions above and below have changed. And so has the operating system.
So what's the connection with "user experience?" A lot I think. Part of it is that you can't plan every detail. But you can create a matrix, like a welcoming garden, where "users" (in this case all the organisms) can come to play. The matrix will change over time and come to re-form itself, partly as a random process and at some level, as part of the design. For sure your control as a designer is minimal and maybe that's the best way. An environment where things run themselves may be the most sustainable.