Nasturtiums are an old-fashioned garden favourite with fragrant flowers in fiery shades of red, orange and yellow. Use the mounding varieties to create a colourful garden border, or add to window boxes and containers for a season-long show of colour. The foliage, flowers and seeds are all edible and are often tossed in salads to add a peppery flavor. A natural companion in the vegetable garden, trapping and discouraging harmful insects from munching on your crops. Sow seed directly in the garden in mid-May, in a sunny spot with light well-drained soil and no fertilizer.