Formal? Architectural? What’s the difference? Well, formal is architectural but also a bit more… formal. Most varieties which suit a formal planting style will also work in an architectural one, but the reverse is not always true. Architectural style tends to also include emphasis on contour line and strong if amorphic shape. Some varieties which provide these strong architectural features cannot be controlled with pruning and are unsuitable for a very formal design which may require long term precision maintenance to maintain lines of the design. All the varieties we suggest below either respond well to clipping or pruning, or have a naturally very symmetrical and regular crown shape.