The present invention provides improved attachment devices fort support lines in plant growth support systems (e.g., trellis systems) and methods of using the same, and offers significant improvements efficiency with regard to assembling and disassembling the support systems for plant and crop growth. The attachment devices may be advantageously used for various vine and low-lying plants (e.g., grapes, tomatoes, etc.) that can be grown in a trellis system or other vertical growth support system. The anchoring devices may include a wire loop for slipping over an end post and a wire strainer bracket attached to the wire loop.