We'd call this poem an interior poem. And not just in the sense that it takes place inside our speaker's mind, in the realm of her emotions. But also because our speaker, from the way she describes her yard, seems separated from the outside, the exterior. Or to put it simply: we think she's in her house.
She's there by her kitchen window in the suburbs of a small city, maybe, looking through her half-reflected face at the spring grass and the plum tree. The poor woman just stands there, stuck between two worlds she no longer feels a part of: the beauty and life of the yard, and the domestic life that has lost its anchor, her husband.