Final answer:
The man in room V is interested in gardening because he finds solace and comfort in nature, as depicted by the detailed descriptions of the garden. Tending to the garden serves as a peaceful and beautiful sanctuary for him, providing respite from other challenges in his life.
Step-by-step explanation:
The man in room V is so interested in gardening because he finds solace and comfort in nature. The detailed descriptions of the garden, such as the mysterious deep-shaded arbors, old-fashioned flowers, and gnarly trees, show how the garden is a peaceful and beautiful sanctuary for him. Even though he may be surrounded by horrid wallpaper or other challenges in his life, the man in room V finds respite and joy in tending to the garden.