Too much landscape design is done with plans. Much too much. I wish more schemes began with models. They are closer to real places than drawings. Models can be made with clay, sand and steel, netting and plaster, wood, polystyrene, card, balsa, earth, anything.
Don't expect to keep the models you make. They may just survive until the client presentation (or the design jury). When you have a photographic record of them, models can be ceremonially destroyed. Presentation models have their uses, but it is a great pity to think of model-making primarily as a presentation technique.