Espalier is a technique in which a plant is:

• A. Grown free-standing
• B. Grafted onto rootstock
• C. Pruned to produce a single stem
• D. Trained flat to a trellis or wall

Answer: (D)

Espalier is a training method that guides a plant to grow flat against a support, like a trellis or wall. It relies on pruning and tying branches to a frame so the growth forms a two‑dimensional, decorative or productive pattern rather than a tall, free-standing tree. This is why it’s about being trained flat along a structure. It’s not simply grown free-standing, nor is it about grafting onto rootstock, and it isn’t just pruning to a single stem—the defining feature is the flat, supported growth on a frame.