Nasturtium
You might be familiar with nasturtiums as a pretty orange flower that trails across gardens and self-seeds year after year. They are often overlooked, however, as a brilliant culinary herb. Nasturtium leaves, flowers, and stems can all be cooked or eaten raw.
Nasturtiums flowers are often used as a showy addition to salads. Their bright colors provide a welcome relief from solid greens and add a somewhat sweet and peppery flavor. The leaves have a much more intense pepper flavor that is similar to watercress. If you don’t want as much pepper flavor in the leaves, they can be cooked, similarly to spinach and can be used as a spinach substitute or complement.
While the seeds can be eaten, they tend to have a rather extreme flavor which many people don’t find particularly palatable.