Cranberry hibiscus is an ornamental perennial, though its early buds are tart and edible.
Tree or vegetable: Cranberry hibiscus is classified as a vegetable, and thus the orlah prohibition does not apply.
Kilei zera’im & kilei hakerem (interplanting mixed species: annuals & grapevines): Since cranberry hibiscus is classified as a vegetable, it should be properly distanced from edible annuals and grapevines.