Shelters for protecting and enhancing the growth of plants reinforced by receiving a retaining structure are provided. The shelters include an outer longitudinal tubular structure having a first-outer-longitudinal-tubular-structure end and a second-outer-longitudinal-tubular-structure end diametrically opposed to the first-outer-longitudinal-tubular-structure end; an inner longitudinal tubular structure positioned within the outer longitudinal tubular structure and having an inner wall, a first-inner-longitudinal-tubular-structure end, and a second-inner-longitudinal-tubular-structure end diametrically opposed to the first-inner-longitudinal-tubular-structure end; and a segmented annular portion positioned between the outer wall and the inner wall. The segmented annular portion may comprise a plurality of segmented annular divider walls defining a plurality of through channels extending from the first-outer-longitudinal-tubular-structure end to the second-outer-longitudinal-tubular-structure end. The plurality of through channels may be configured to receive at least one retaining structure.
