Orchids are one of the two most immense families of flowering plants, with an estimated 28.000 species and over 100.000 hybrids and cultivars. Most Orchids have a racemose inflorescence.
2. Oriental Lily
Created by crossing interspecific hybrids and some certain Lilies species, Oriental Lilies have intensely fragrant, colorful flowers with striking spots in mid to late summer.
3. Old Man of the Andes
The spiky body of Old Man of the Andes is covered with white, beard-like hairs that give the appearance of a frail elderly, hence the name. It has red flowers and stems up to 3m tall.
4. Obovate Peony
Suited to open woodlands and shady gardens, Obovate Peony or Paeonia obovata has rose, purple-red or white, cup-shaped flowers and is appropriate as a low herbaceous hedge.
5. Ox-Eye Daisy
Highly vigorous and disease-free, Ox-Eye Daisy is known for its floriferous display of white single blooms with yellow centers. This invasive weed has several names, including Marguerite, Field Daisy, and Dog Daisy.
6. Oyster Plant
The Oyster Plant is a widespread compact houseplant distinguished by its elongate, lanceolate, striped, green leaves with purplish undersides and small, pink or white flowers.
7. Oregon Grape
Oregon Grape bears dense clumps of yellow blooms, followed by blackish-blue, distasteful berries. In winter, its foliage takes on shades of scarlet to burgundy, striking in the grey landscape.
8. Ohio Spiderwort
Ohio Spiderwort (Bluejacket) is characterized by its violet-blue blossoms tending to flower in the morning and shrivel from the mid-day heat. This aggressive plant is not suitable for a small garden.
Osteospermum species (African Daisies) are perfect for those who desire long-lasting, fragrant, colorful blooms for their landscape. These annuals bloom freely in spring, fall, or cool summer climates.
10. Oriental Poppy
Oriental Poppies (Papaver orientale) feature large, silky-satin blossoms in shades of orange, red, pink, or white. They set your landscape ablaze with striking visuals from late spring to early summer.
11. Ornamental Onion
In the spring and early summer, Ornamental Onions or Alliums are topped with cheerful spherical clusters of flowers in shades of purple and pink in a long-lasting display that can make you wow.
12. Obedient Plant
Otherwise known as False Dragonhead, the Obedient plant has snapdragon-like, pink to lavender blooms in terminal spikes. Each flower is “obedient” and can stay in a new position if bent, making it fun to play with.
13. Oleander Plant
The Oleander plants (Nerium oleander) are tough, long-blooming, ornamental shrubs with beautiful clusters of red, pink, or white flowers and can be trained into single-trunk trees.
14. Old Lady Cactus
Thriving in indoor settings with just a bit of care, Old Lady Cactus or Mammillaria hahniana features precious reddish-purple blossoms on stems covered with white bristles and spines.