Flowers That Start With O
Discover 60+ flowers beginning with O — their names, meanings, origins, and unique characteristics.
Oakleaf Hydrangea
A deciduous shrub native to the southeastern United States, featuring large, cone-shaped white flower panicles and distinctively lobed, oak-like foliage that turns deep red in autumn.
Oat Grass
A perennial ornamental grass that produces delicate, oat-like flower spikes, often used in dried floral arrangements for its rustic, airy texture and golden-brown hue.
Obedient Plant
Known botanically as Physostegia virginiana, this North American native features spikes of tubular pink or white flowers that remain in place when pushed, hence its unique common name.
Oberonia
A genus of miniature epiphytic orchids found in tropical Asia and Africa, characterized by fan-shaped leaves and tiny, densely packed flowers arranged in long, slender, drooping racemes.
Ochna serrulata
Commonly known as the Mickey Mouse plant, this South African shrub produces yellow flowers followed by bright red sepals and black berries that resemble a cartoon face.
Oconee Bells
Shortia galacifolia is a rare, low-growing woodland wildflower native to the Appalachian Mountains, prized for its delicate, bell-shaped white or pale pink spring blossoms.
Octomeria
A genus of orchids native to tropical America, featuring small, clustered flowers with eight pollinia, often found growing on tree trunks in humid, high-altitude cloud forests.
Odontoglossum
A genus of cool-growing orchids native to the high Andes, famous for their spectacular, star-shaped, often spotted or patterned flowers that are highly prized by orchid collectors.
Odontonia
A popular intergeneric orchid hybrid resulting from a cross between Odontoglossum and Miltonia, known for large, showy, and often fragrant flowers in a wide array of colors.
Oenothera
Commonly known as Evening Primrose, this genus includes many species that produce vibrant yellow, white, or pink flowers which typically open at dusk to attract nocturnal pollinators.
Oenothera biennis
The common evening primrose, a biennial wildflower native to North America, produces tall spikes of fragrant yellow flowers that open rapidly in the evening and close by morning.
Oenothera fruticosa
Known as the narrow-leaf evening primrose, this perennial garden plant features bright yellow, cup-shaped flowers that bloom during the day, unlike many other members of its genus.
Oenothera macrocarpa
The Missouri evening primrose is a low-growing perennial with large, lemon-yellow flowers and winged seed pods, native to the central United States and excellent for rock gardens.
Oerstedella
A genus of reed-stemmed orchids native to Central and South America, often featuring clusters of small, colorful flowers and distinctively jointed, cane-like stems similar to Epidendrum.
Old Man Cactus
Cephalocereus senilis is a columnar cactus covered in long, white, hair-like spines, which occasionally produces nocturnal, funnel-shaped pink or yellow flowers in its native Mexico.
Old Man's Beard
Clematis vitalba is a vigorous climbing vine native to Europe, known for its fragrant, greenish-white flowers followed by long, feathery, persistent seed heads that resemble white hair.
Oleander
Nerium oleander is a hardy, evergreen shrub native to the Mediterranean, producing clusters of showy pink, red, or white flowers, though all parts of the plant are highly toxic.
Olearia
Commonly called the daisy bush, this genus of shrubs and small trees native to Australia and New Zealand produces masses of white or blue daisy-like flowers in summer.
Olive
Olea europaea is a slow-growing evergreen tree native to the Mediterranean, producing small, inconspicuous, fragrant white flowers that eventually develop into the well-known edible olive fruit.
Omphalodes
Commonly known as navelwort, this genus of spring-flowering perennials produces charming, forget-me-not-like blue or white flowers, often used as ground cover in shaded woodland garden settings.
Oncidium
Known as dancing-lady orchids, this diverse genus from the Americas produces long, arching sprays of small, yellow, and brown flowers that appear to flutter in the breeze.
Onion Flower
Allium cepa, when allowed to bolt, produces a large, spherical umbel of tiny, star-shaped white or purple flowers that are highly attractive to bees and other garden pollinators.
Ononis
Commonly known as restharrow, this genus of pea-family plants features pink or yellow flowers and tough, woody roots, often found growing in dry, sandy, or rocky European meadows.
Onopordum acanthium
The Scotch thistle is a tall, biennial plant with large, spiny leaves and striking, globe-shaped purple flower heads that are a favorite of butterflies and goldfinches in summer.
Onychium
A genus of ferns that produces delicate, finely divided fronds, often grown for their ornamental foliage rather than flowers, native to temperate and tropical regions of Asia.
Ophiopogon
Commonly known as lilyturf, this genus produces spikes of small, bell-shaped white or lilac flowers hidden among grass-like foliage, often followed by deep blue, berry-like fruits.
Ophrys
Known as bee orchids, this genus of terrestrial orchids from Europe and the Mediterranean has evolved flowers that mimic female insects to attract pollinators, a fascinating botanical adaptation.
Opuntia
The prickly pear cactus genus, native to the Americas, produces large, waxy, cup-shaped flowers in shades of yellow, orange, or red, followed by edible, colorful, spiny fruits.
Orange Blossom
The fragrant, white, waxy flowers of the Citrus sinensis tree, symbolizing purity and fertility, are widely used in bridal bouquets and perfumes across the Mediterranean and beyond.
Orange Daylily
Hemerocallis fulva is a vigorous, clump-forming perennial with large, trumpet-shaped orange flowers that bloom for a single day, often found naturalized along roadsides throughout North America.
Orange Hawkweed
Hieracium aurantiacum is a perennial wildflower with vibrant, flame-orange, dandelion-like flowers, often considered an invasive species in many parts of North America and Europe.
Orchid Cactus
Epiphyllum hybrids are prized for their spectacular, large, often fragrant, night-blooming flowers in shades of pink, red, white, or yellow, originating from the tropical forests of America.
Orchid Tree
Bauhinia variegata is a small tropical tree known for its large, orchid-like, fragrant flowers in shades of pink, purple, or white, blooming profusely during the spring season.
Orchidantha
A genus of rare, low-growing plants from Southeast Asia, known for their unusual, orchid-like flowers that are often hidden near the base of the plant and emit a scent.
Orchis
A genus of terrestrial orchids native to the Northern Hemisphere, featuring spikes of small, often spotted flowers that arise from underground tubers in meadows and woodland habitats.
Oregano
Origanum vulgare is a culinary herb that produces small, tubular, pink or purple flowers in late summer, which are highly attractive to bees and other beneficial garden insects.
Oregon Grape
Mahonia aquifolium is a hardy evergreen shrub native to the Pacific Northwest, featuring clusters of bright yellow, fragrant flowers in spring followed by dark blue, edible berries.
Oriental Lily
A group of hybrid lilies known for their large, intensely fragrant, trumpet-shaped flowers in shades of white, pink, and crimson, often featuring spotted petals and prominent stamens.
Oriental Poppy
Papaver orientale is a perennial poppy native to the Caucasus, famous for its massive, papery, cup-shaped flowers in brilliant shades of orange, red, pink, or white in spring.
Orlaya grandiflora
Commonly known as white laceflower, this elegant annual produces flat-topped umbels of intricate, lacy white flowers, making it a popular choice for cottage gardens and cut flower arrangements.
Ornithogalum
Known as Star of Bethlehem, this genus of bulbous plants produces spikes of star-shaped white or orange flowers, often with a contrasting stripe on the back of petals.
Orobanche
Commonly known as broomrape, this is a genus of parasitic plants that lack chlorophyll and produce spikes of tubular, often yellowish or brownish flowers, attaching to host roots.
Orontium aquaticum
Golden club is an aquatic perennial native to North America, featuring a unique, slender, yellow-tipped flowering spadix that rises above the water surface in early spring.
Orthrosanthus
Known as morning iris, this genus of perennials from Australia and South America produces beautiful, short-lived, sky-blue flowers that open in the morning and close by afternoon.
Oryza
The rice genus produces small, inconspicuous, wind-pollinated flowers arranged in panicles, which are essential for the production of the world's most important staple grain crop.
Osmanthus
A genus of evergreen shrubs and trees known for their small, intensely fragrant, white or yellow flowers that bloom in autumn, often used in tea and traditional perfumery.
Osmunda
A genus of large, primitive ferns known as royal ferns, which produce fertile fronds that look like flower spikes, often found in damp, shaded, and acidic woodland environments.
Osteospermum
Commonly known as the African daisy, this genus features vibrant, daisy-like flowers in shades of purple, pink, white, or yellow, often with a dark, contrasting center eye.
Ostericum
A genus of perennial herbs in the carrot family, producing large, compound umbels of small, white or greenish flowers, often found in meadows and along stream banks in Asia.
Othonna
A genus of succulent plants from South Africa, often producing bright yellow, daisy-like flowers, and widely grown by collectors for their unique, fleshy, and often caudiciform stems.
Ouvirandra
Now classified under Aponogeton, the Madagascar lace plant is a unique aquatic species that produces delicate, white, orchid-like flowers on a stalk above the water's surface.
Oxalis
Known as wood sorrel or shamrock, this genus features clover-like leaves and delicate, five-petaled flowers in shades of pink, white, or yellow, which often fold up at night.
Oxalis adenophylla
A charming, low-growing alpine species with silver-grey, fern-like foliage and large, funnel-shaped, pale pink flowers with dark veins, native to the mountains of Chile and Argentina.
Oxalis corniculata
Creeping wood sorrel is a common, often invasive weed with small, yellow flowers and trifoliate leaves, frequently found in gardens and greenhouses across many parts of the world.
Oxalis triangularis
Known as the purple shamrock, this popular houseplant features deep purple, triangular leaves and delicate, pale pink or white flowers that open and close based on light levels.
Oxera
A genus of climbing shrubs from New Caledonia, producing large, waxy, trumpet-shaped white flowers that hang in clusters, often pollinated by birds in their native tropical habitat.
Oxydendrum arboreum
The sourwood tree is native to the eastern United States, producing long, drooping racemes of fragrant, white, lily-of-the-valley-like flowers in mid-summer, followed by brilliant red autumn foliage.
Oxypetalum
Known as blue milkweed, this genus produces star-shaped, sky-blue flowers that are highly prized by florists for their unique color and long-lasting quality in cut flower arrangements.
Oxytropis
Commonly known as locoweed, this genus of perennial herbs in the pea family produces spikes of purple, white, or yellow flowers, often found in alpine or arctic regions.
Ozothamnus
A genus of shrubs in the daisy family native to Australia and New Zealand, known for their clusters of small, papery, white or pink flowers that are excellent for drying.
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