Origanum 'Amethyst Falls' is an ornamental oregano with cool shrimp-like pink and amethyst flowers.

Origanum 'Bellissimo' is an ornamental oregano with pendulous purple-pink and white hop-like flower heads and green hop-like foliage.

Origanum 'Drops of Jupiter' is an ornamental oregano with pink flowers and aromatic, chartreuse-yellow foliage.

Origanum 'Kent Beauty' has cute shrimp-like, pink flowers held in pendulous clusters from blue-green foliage.

Ornithogalum nutans has spikes of fragrant, outward-facing to slightly nodding, star-shaped flowers coloured white and grey-green.

Ornithogalum pyramidale forms pyramidal spikes of fragrant, outward-facing, pure white, star-shaped flowers with green-striped reverses in early summer.

Ornithogalum reverchonii is a rare star-of-Bethlehem with spikes of fragrant, outward-facing, pure white, bell-shaped flowers on stems 24-36 inches tall.

Ornithogalum saundersiae is a South African bulb with clusters of fragrant, upward facing, white flowers on long stems.

Orostachys ‘Chinese Hat’ is a succulent hybrid that forms succulent rosettes of pale silver/grey foliage with yellow flowers.

Orostachys japonica is a hardy rosette succulent with many cylindrical, pointed, light green leaves that can flush orange.

Osmanthus fragrans f. aurantiacus has small, orange, extremely fragrant, edible flowers famous in China for use in teas and other foods.

Osmanthus fragrans f. thunbergii has small, pale yellow, extremely fragrant, edible flowers famous in China for use in teas and other foods.

Osmunda cinnamomea, the cinnamon fern, has lush green vegetative fronds and cool rusty orange sporophytic fronds.

Othonna capensis or little pickles is an extremely hardy ground-covering succulent with blue-green leaves and yellow daisy flowers.