An apparatus and method to isolate at least a part of a plant from passage of things or materials of certain size or characteristics. In one aspect, a shroud or sock (10) of material can be removably placed over at least a part of the plant (3) with a releasable closure (13). The material is highly permeable to air and moisture and is substantially light transmissive. However, it has a pore size which blocks the undesirable materials or things (e.g., pollen or insects). The material can have a relatively light weight so that it can be optionally suspended by the plant (3) without significant effect on the growth or health of the plant. The material can have substantial tensile strength to resist deformation, tearing, or puncture during normal handling or in moderate to high winds. It can be utilized to provide a barrier over a part of a plant, substantially an entire plant, or a plurality of plants.