Flowers That Start With O

Here are the varying types of flowers with names that begin with the letter O. With an emphasis on common and easy to grow varieties.

Obedient Plant

Physostegia virginiana, the obedient plant, obedience or false dragonhead got its name because you can bend the individual flowers in any direction

Obedient plant (Physostegia virginiana)

Obovate Peony

This hybrid peony has very early single blooms that can range from bright red to pink to white in color and grey-green leaves.

This plant has white to purple-red flowers and its lower leaves consist of no more than nine leaflets or segments. 

Obovate peony (Paeonia obovata)

Ohio Spiderwort

The Ohio Spiderwort is a herbaceous perennial plant. The variety pictured below with blue flowers is known as the blue jacket.

Ohio spiderwort (Tradescantia ohiensis)

Old Lady Cactus

In the spring or summer, this cactus sprouts red or purple flower around the top.

Old Lady Cactus (Mammillaria Hahniana)

Old Man of the Andes

Old Man of the Andes (Oreocereus Celsianus)

Oleander Plant

Nerium oleander, usually referred to as oleander, is an upright, rounded evergreen sub-tropical to tropical shrub that produces purple, pink or white five-petaled funnel-shaped flowers during the summer to fall months.

Oleander Plant (Nerium Oleander)


Orchids occur in every habitat/terrain on the planet, except for Antarctica and true deserts.

Orchid. (Orchidaceae).

Oregon Grape

This plant sprouts thick bunches of yellow flowers in early spring, succeeded by dark bluish-black berries. In 1899 Oregon adopted the Oregon Grape (Berberis aquifolium) as the Official State Flower.

Oregon Grape (Mahonia)

Oriental Lily

Lilium ‘Stargazer’ is a hybrid lily of the ‘Oriental group’. Oriental lilies are known for their fragrant perfume, blooming mid-to-late summer. Stargazers are easy to grow and do best in full sunlight. 

Oriental Lily. (Stargazer).

Oriental Poppy

Oriental Poppy. (Papaver).

Ornamental Onion

Wild onions have flat leaves while wild garlic has round leaves.

Ornamental Onion. (Allium).


Osteospermum. (Calendula Family, Cape Daisy).

Oyster Plant

It also goes by the names bear’s breeches, sea dock, bearsfoot, and it is considered to be an invasive species in some regions.

Oyster Plant. (Acanthus mollis).

Ox Eye Daisy

Leucanthemum vulgare (Ox-eye Daisy, oxeye daisydog daisy) is generally cultivated and ready as a perennial flowering ornamental plant for gardens.

Ox Eye Daisy. (Leucanthemum vulgare).

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