Pelargonium citronellum or Citronella Pelargonium. The attractive and fragrant foliage makes this species an interesting subject for the garden. It can also be grown as a culinary herb or to flavour puddings. Although the foliage is fragrant all the time, it is during the warmer weather that you’ll notice it, because the citronella (lemon-scented chemical in the leaf) is volatile at high temperatures. This plant can be used as a companion plant to repel pests, as the lemon scent has natural insecticidal properties. The leaves can also be used in potpourri and finger bowls.