How is a tree or large shrub with one short, straight trunk and a dense head of foliage referred to?

A tree or large shrub with one short, straight trunk and a dense head of foliage is referred to as a standard. This term describes a plant trained to grow upward on a single trunk, giving it a prominent and distinct shape that is often desired in landscapes and gardens. The dense head of foliage at the top not only serves an aesthetic purpose but also provides shade and visual interest.

The characteristics of a standard tree typically make it a focal point in garden design. For instance, these trees are often used to create a vertical element against walls or in open spaces. The defined structure also allows for easier maintenance and care, as the foliage can be more accessible for pruning and health checks.

In contrast, topiary refers to the art of shaping plants into decorative forms, bonsai involves cultivating small trees in a pot to mimic the shape of a full-sized tree, and espalier is a method of training plants to grow flat against a structure. Each of these practices embodies different horticultural techniques and aesthetic goals, differing significantly from the definition and application of a standard tree.