Flowers That Start With ‘O’: 50 Beautiful Varieties to Admire

Hundreds of thousands of species of flowers grow all around the world, offering up their diversity, beauty, and allure for the appreciation of botanists, florists, gardeners, and greenthumbs everywhere. To help you discover more flowers, we’re taking a different approach and rounding up some of the most beautiful and exciting flowers alphabetically. Continue reading to learn about 50 flowers that start with the letter O, along with their pictures, descriptions, native ranges, exciting facts, symbolic meanings in the language of flowers, and more.

Flowers That Start With The Letter O

50 Beautiful Flowers That Start With the Letter O:

1. Oakleaf Hydrangea

Oakleaf Hydrangea are beautiful types of flowers that start with the letter O

The oakleaf hydrangea is a woody, deciduous shrub that produces lush, green, lobed leaves that resemble the foliage of an oak tree. 

Unlike other hydrangeas from the Hydrangeaceae (hydrangea) plant family, which have ball-shaped flower clusters, the oakleaf hydrangea produces cone-shaped clusters of small, snowy-white flowers. The flowers start out white, deepen to pink through the summer, and once dried in fall they turn rusty brown. 

In the language of flowers, hydrangea symbolizes a boaster and heartlessness or represents the phrase, “You are cold.”

Scientific Name:Hydrangea quercifolia
Native Range:Southeastern United States
Flowering Season:April through July

2. Obedient Plant

Obedient Plant

A member of the Lamiaceae (mint) plant family, the obedient plant produces erect clumps of stems with squared sides and lanceolate leaves. 

The plants grow to be about five feet in height, and on the ends of the stems, they produce long, cone-shaped racemes of pinkish-purple, tubular flowers that have a shape similar to snapdragons. 

Some cultivars produce pure white, pink, and lavender flowers. Other common names for the obedient plant include obedience, fall obedient plant, Virginia lions-heart, and false dragonhead.

Scientific Name:Physostegia virginiana
Native Range:Most of Canada, northern Mexico, and the eastern and central United States
Flowering Season:August through November

3. Ochagavia


The Ochagavia plant genus contains four accepted species of flowering plants belonging to the Bromiliaceae (bromeliad) plant family. 

These flowers that start with the letter O produce thick rosettes of leathery, strap-like foliage and a central spike-like flowerhead in shades of light pink and red. The flowerhead gives way to a spiky, brown-colored fruit that resembles its cousin from another genus, the pineapple.

Scientific Name:Ochagavia spp.
Native Range:Southern and Central Chile
Flowering Season:Late summer through early fall

4. October Daphne

October Daphne are beautiful types of flowers that start with the letter O

A member of the Crassulaceae (stonecrop) plant family, October daphne (also called October stonecrop) is a favorite for all kinds of gardens thanks to its attractive, succulent-like foliage that starts out in a shade of silvery bluish-green and warms throughout the season, developing pinkish-red margins. 

October daphne is also stunning when it blooms in early autumn. The plants produce abundant, globe-shaped clusters of fuzzy, pink flowers that attract scores of butterflies.

Scientific Name:Hylotelephium sieboldii (syn. Sedum sieboldii)
Native Range:Japan and south-central China
Flowering Season:Early to mid-fall

5. Oenothera biennis (Common Evening Primrose)

Oenothera biennis (Common Evening Primrose)

A member of the Onagraceae (evening primrose) plant family, the common evening primrose has a two-year lifespan and grows to be just over five feet in height. The plants produce terminal rosettes of yellow, four-petaled flowers in the first year and loose spirals of flowers during the second blooming season. It’s this species of primrose from which evening primrose oil is produced.

Scientific Name:Oenothera biennis
Native Range:Southern Canada, most of the United States, and northern Mexico
Flowering Season:Late spring to late summer

6. Oenothera speciosa (Pink Evening Primrose)

Oenothera speciosa (Pink Evening Primrose) are beautiful types of flowers that start with the letter O

Another evening primrose, the pink evening primrose, is a perennial wildflower that has a more diminutive form, reaching just about two feet in height. It produces terminal rosettes of cup-shaped flowers in a delicate shade of rosy pink that fades to white and bright yellow at their centers. 

These flowers that start with the letter O fade to pure white as they mature. In the language of flowers, evening primrose symbolizes inconstancy, sympathy, and silent love.

Scientific Name:Oenothera speciosa
Native Range:South-central United States and Northern Mexico
Flowering Season:February through October

7. Ohio Goldenrod

Ohio Goldenrod

A member of the Asteraceae (daisy, composite, aster, and sunflower) plant family, the Ohio goldenrod is an herbaceous perennial that grows in erect clumps up to about three feet in height. 

Ohio goldenrods produce long, slender leaves and flat-topped, terminal panicles of small, densely arranged golden-yellow flowers. These flowers are an essential food source for native bees. In the language of flowers, goldenrod symbolizes precaution and eloquence.

Scientific Name:Solidago ohioensis
Native Range:The Great Lakes Region
Flowering Season:September and October

8. Okra


Abelmoschus esculentus is a species of flowering plant that is most popularly known as okra, an ingredient commonly used in dishes of the southern United States and regions around the world. 

Okra plants typically reach about five feet tall and produce hibiscus-like yellow flowers with purplish centers. Several cultivars have red, orange-red, and pink flowers with white centers. Okra is most commonly planted for its edible fruit (seed pods).

Scientific Name:Abelmoschus esculentus
Native Range:Myanmar, India, and Bangladesh
Flowering Season:Throughout the growing season until frost

9. Old Man’s Beard

Old Man's Beard are beautiful types of flowers that start with the letter O

Clematis vitalba (commonly called old man’s beard or traveler’s joy) is a flowering, deciduous shrub that belongs to the Ranunculaceae (buttercup) plant family. 

These flowers that start with the letter O feature a prominent tuft of greenish-white flowers surrounded by a corona of white sepals that are often fluffy or feathery in texture. As a result, the flowers look like they have white beards. In certain parts of the United States, this species is considered invasive

Clematis symbolizes artifice, mental beauty, and perseverance in the language of flowers.

Scientific Name:Clematis vitalba
Native Range:The Mediterranean region
Flowering Season:July through September

10. Old Man’s Bones

Old Man's Bones

A member of the Crassulaceae plant family, Sedum divergens is a species of flowering plant with bluish-green, succulent leaf segments that are produced in trailing rosettes and clusters of bright-yellow, star-shaped flowers. 

The common name “old man’s bones” refers to the arrangement of the plant’s leaf segments, which resemble ball joints. Other common names for Sedum divergens include Pacific stonecrop, Cascade stonecrop, and spreading stonecrop.

Scientific Name:Sedum divergens
Native Range:North American Pacific Coast from Alaska to California
Flowering Season:Summer

11. Old Man’s Whiskers

Old Man's Whiskers

A member of the Rosaceae (rose) plant family, old man’s whiskers is an herbaceous, perennial, flowering plant. The plants appear in clumps of fern-like, bluish-green foliage and produce reddish-purple flowers that rise above the foliage. 

These flowers that start with the letter O give way to alluring, silvery-white, feathery plumes of seeds that blow in the wind like whiskers. Additional common names include grandfather’s beard, prairie smoke, torchflower, long-plumed purple avens, three sisters, and lion’s beard.

Scientific Name:Geum triflorum
Native Range:Canada and the western and northern United States
Flowering Season:May and June

12. Oleander


Nerium oleander (commonly referred to simply as oleander or nerium) is an evergreen shrub belonging to the Apocynacea (dogbane) plant family. The plants have short, blade-like leaves and produce clusters of single or double, pinwheel-shaped flowers in shades of white, cream, yellow, red, pink, or purple. 

All parts of oleander plants are toxic. However, they taste bitter to animals and people, making cases of poisoning rare. The sap can also irritate skin, so wearing gloves when working with oleander plants is best. 

In the language of flowers, oleander means beware, and “Divine love overcomes all difficulties.”

Scientific Name:Nerium oleander
Native Range:The Mediterranean and south-central Asia
Flowering Season:Early summer to mid-fall

13. Olearia spp. (Daisy Bush)

Olearia spp. (Daisy Bush)

One hundred and fifty-seven species of flowering shrubs, commonly called daisy bushes, belong to the Olearia genus within the Asteraceae plant family. Plants of this species grow to various sizes and produce individual flowers or flowers in clusters. 

The flower heads can be single or double, consisting of daisy-like ray and disc florets with white, purple, or yellow ray florets and yellow or purplish disc florets at the centers. 

Several cultivars are planted for ornamental purposes and have earned the Royal Horticultural Society’s Award of Garden Merit.

Scientific Name:Olearia spp.
Native Range:New Guinea, Australia, and New Zealand
Flowering Season:Late spring to early summer

14. One-Flowered Wintergreen

One-Flowered Wintergreen

A member of the Ericaceae (heath or heather) plant family, Moneses uniflora is the only species of its genus. It is an herbaceous perennial that produces a small rosette of ovate, slightly toothed leaves. 

Each plant produces a single, fragrant white flower. The flowers are nodding with prominent stamens and five back-turned petals, which appear like a reading lamp. 

With a wide native distribution, it has many common names, including one-flowered wintergreen, single delight, wood nymph, frog’s reading lamp, St. Olaf’s candlestick, Star of Bethlehem, or shy maiden.

Scientific Name:Moneses uniflora
Native Range:Temperate Northern Hemisphere
Flowering Season:May through August

15. Onion


Allium cepa is the scientific name of a root vegetable that calls Turkmenistan home but grows all around the world and finds itself in dishes from all around the world, too. 

This vegetable is the onion, and it belongs to the Amaryllidaceae (amaryllis) plant family. While onions are almost always grown for their edible, aromatic roots, they also produce attractive flower clusters. The clusters are spherical and filled with fuzzy flowers that are either white or a delicate shade of light purple.

Scientific Name:Allium cepa
Native Range:Turkmenistan
Flowering Season:July and August

16. Onosma (Golden Drops)

Onosma (Golden Drops) are beautiful types of flowers that start with the letter O

A member of the Boraginaceae (borage) plant family, the Onosma genus contains 227 accepted species of flowering plants, commonly called golden drops. 

While their pendulous, bell-shaped flowers are often golden yellow in color, they are also commonly pink, white, or purple. The flowers appear in clusters and emerge from buds on stems and foliage almost entirely covered with white hairs.

Scientific Name:Onosma spp.
Native Range:Northern Africa and Eurasia
Flowering Season:May through August

17. Opuntia (Prickly Pear)

Opuntia (Prickly Pear)

A member of the Cactaceae (cactus) plant family, the Opuntia genus contains 144 species of flowering cacti, commonly called prickly pears. Prickly pears mostly grow into shrub-like formations of spiny, pear-shaped cactus pads. However, a few species grow into tree-like formations. 

These flowers that start with the letter O are cup-shaped and appear in clusters in shades of pink and yellow. Prickly pear cacti produce edible fruits, popular food sources throughout the Americas. Their immature pads are also edible and commonly used in traditional dishes in regions where they grow naturally.

Scientific Name:Opuntia spp.
Native Range:The Americas
Flowering Season:Spring and summer (depending on species)

18. Orange Ball Tree

Orange Ball Tree

A member of the Scrophulariaceae (figwort) plant family, Buddleja globosa (commonly called orange ball tree) is a large, flowering shrub. Older growth on the shrub has grey bark, while younger shoots and branches are green and covered with fine hairs. They produce elliptical, prominently veined foliage and ball-shaped terminal clusters of bright-orange flowers. 

The flowers are densely clustered, giving the balls a honeycomb-like look that pairs perfectly with their sweet, honey-like scent.

Scientific Name:Buddleja globosa
Native Range:Chile and southern Argentina
Flowering Season:Late spring to early summer

19. Orange Blossom

Orange Blossom are beautiful types of flowers that start with the letter O

A member of the Rutaceae (rue or citrus) plant family, Citrus x aurantium is a hybrid of Citrus maxima (pomelo) and citrus reticulata (mandarin). This hybrid tree produces flowers commonly called orange blossoms and fruits known as Valencia oranges, navel oranges, and blood oranges. 

The state flower of Florida, orange blossoms are prized for several uses, including their sweet fragrance, teas, and infusions made with their petals, and their part in making orange blossom honey.

Scientific Name:Citrus x aurantium (syn. Citrus x sinensis)
Native Range:Human-cultivated hybrid
Flowering Season:Late May through early June

20. Orange Coneflower

Orange Coneflower

Rudbeckia fulgida (commonly called orange coneflower, orange rudbeckia, or perennial black-eyed Susan) belongs to the Asteraceae plant family. The plants grow in clumps up to about four feet in height. 

They have pointed, ovate foliage that is covered in hairs and produce showy flowerheads that consist of bright-yellow ray florets around prominent, dark brown, almost-black disc florets. When in bloom, the flowers appear in profusion and attract various native birds.

Scientific Name:Rudbeckia fulgida
Native Range:Eastern North America
Flowering Season:July through October

21. Orange Daylily

Orange Daylily

Hemerocallis fulva is a species of herbaceous perennial that grows and spreads via tuberous root systems. The most widely used common name for the plant is the orange daylily, which refers to the plant’s orange-colored flowers that last for only one day in addition to their superficial resemblance to flowers of true lilies. The orange daylily, however, is not a lily, as it belongs to the Asphodelaceae plant family.

Scientific Name:Hemerocallis fulva
Native Range:Eastern Asia
Flowering Season:Mid to late summer

22. Orange Jessamine

Orange Jessamine are beautiful types of flowers that start with the letter O

A member of the Rutaceae plant family, Murraya paniculata is not a citrus plant, but its white and cream-colored flowers resemble orange blossoms in appearance and fragrance. 

Common names for this evergreen shrub or tree include orange jessamine, orange jasmine, mock orange, and china box. These plants are commonly grown as ornamental plants individually and in groups to form privacy screens or hedges.

Scientific Name:Murraya paniculata
Native Range:Australasia
Flowering Season:Year-round in warm climates

23. Orange Milkwort

Orange Milkwort

A member of the Polygalaceae (milkwort) plant family, Polygala lutea is commonly called orange milkwort. Orange milkwort is an herbaceous annual or perennial plant that can grow to about 20 inches in height. 

These flowers that start with the letter O produce pineapple-like flowerheads in bright shades of orange that fade to yellow when dried. The orange color distinguishes these from other milkworts, as most milkworts have pink, white, or yellow flowerheads.

Scientific Name:Polygala lutea
Native Range:Atlantic and Gulf Coasts of the United States
Flowering Season:February through November

24. Orange Star Flower

Orange Star Flower

Ornithogalum dubium is a bulbous perennial belonging to the Asparagaceae (asparagus) plant family. 

The plants are small, growing to about one foot in height and six inches in diameter. They produce rosettes of paddle-shaped leaves and tightly arranged, round clusters of orange, star-shaped flowers with dark centers. 

Common names for the plants include orange star flower, sun star, and star of Bethlehem.

Scientific Name:Ornithogalum dubium
Native Range:South Africa
Flowering Season:Late winter to spring

25. Orchid

Orchids are beautiful types of flowers that start with the letter O

The orchid plant family (Orchidaceae) currently contains 705 accepted genera made up of about 28,000 different species, making it the second-largest flowering plant family. 

Most types of orchids typically have small seeds, bilateral symmetry, back-bent (resupinate) petals, fused stamens, and modified carpels. 

In the language of flowers, different orchids have different symbolic meanings, including a belle (general), industry (bee orchid), gaiety (butterfly orchid), error (fly orchid), disgust (frog orchid), and adroitness (spider orchid).

Scientific Name:Orchidaceae spp.
Native Range:Cosmopolitan
Flowering Season:Various seasons (depending on the species)

26. Orchid Cactus

Orchid Cactus

A member of the Cactaceae plant family, the Epiphyllum genus contains ten species of flowering cacti, commonly called orchid cactuses. Although they are technically cacti, these plants do not resemble the cacti you are likely familiar with (i.e., thick, pad-like leaf segments and spikes). 

These flowers that start with the letter Oi have orchid-like leaves and stems and produce lovely, pointed, star or pom-pom-like flowers in shades of white, yellow, red, pink, and purple.

Scientific Name:Epiphyllum spp.
Native Range:Mexico, Central America, and South America
Flowering Season:Early spring (white and yellow), mid-spring (red and pink), and late spring and early summer (purple and deep red)

27. Orchid Tree

Orchid Tree

A member of the Fabaceae (pea or legume) plant family, Bauhinia variegata is a species of small to medium-sized, flowering tree commonly called orchid tree or mountain ebony. The trees have light-green leaves connected at the base in pairs, like butterfly wings. When in bloom, the trees produce an abundant canopy of purple, white, and bright pink flowers that resemble the blossoms of orchids.

Scientific Name:Bauhinia variegata
Native Range:Southern Asia
Flowering Season:Late winter to early spring

28. Oregano


You can find Oregano vulgare in a bottle on most spice racks labeled with its common name, oregano. Like many members of the Lamiaceae (mint, sage, or deadnettle) plant family, oregano is prized for its aromatic properties and is commonly used as a fragrant herb in cooking. 

It is prevalent in Italian cuisine. The plants themselves are bushy perennials with woody stems and rounded leaves. They produce corymbs of small white or purple flowers.

Scientific Name:Origanum vulgare
Native Range:The Mediterranean Region
Flowering Season:Midsummer to fall

29. Oregon Grape

Oregon Grape are beautiful types of flowers that start with the letter O

Commonly called Oregon grape or holly-leaved barberry, Mahonia aquifolium is a bushy flowering plant that belongs to the Berberidaceae (barberry) plant family. The bushes have ovate leaves with wavy margins and bright yellow flowers in densely clustered racemes. 

These flowers that start with the letter O give way to grape-like berries in dark, bluish-purple. Though somewhat sour, the berries are edible, commonly used to make jams, and even fermented to make wine.

Scientific Name:Mahonia aquifolium
Native Range:The Pacific Coast from California to British Columbia and inland into Montana
Flowering Season:February through May

30. Oriental Bittersweet

Oriental Bittersweet

A member of the Celastraceae (bittersweet or staff-vine) plant family, Celastrus orbiculatus is a species of flowering, woody vine that is commonly called oriental bittersweet, Asian bittersweet, Chinese bittersweet, or round-leaved bittersweet. 

The plants are composed of vines with silver to red bark that can grow to be up to almost four inches in diameter. On their own, they develop into thickets. Growing near trees, they can climb up to 40 feet. 

Sometimes, these vines even strangle trees or break them under their excessive weight. They have rounded leaves and produce small clusters of green flowers that produce red seeds in yellow pods.

Scientific Name:Celastrus orbiculatus
Native Range:Eastern Asia
Flowering Season:May and June

31. Oriental Lily

Oriental Lily

The term “Oriental lily” refers to a group of hybrid lilies characterized by their vibrant colors, strong fragrances, and large flowers. Some of the most prized lilies of this group include Lilium ‘Stargazer,’ Lilium ‘Starfighter,’ Lilium ‘Casa Blanca,’ and Lilium ‘Sumatra.’ This group of lilies features blossoms in shades of red, pink, orange, yellow, and white.

Scientific Name:Lilium spp. (Oriental Group Hybrids)
Native Range:Human-cultivated hybrids
Flowering Season:Mid to late summer

32. Oriental Poppy

Oriental Poppy

Papaver orientale (commonly called Oriental poppy) is a flowering perennial that belongs to the Papaveraceae (poppy) plant family. They produce clumps (1’x2′) of finely dissected, hairy foliage and large blossoms atop slender stems. 

These flowers that start with the letter O are typically scarlet, with black markings near the base of the petals. Cultivars, however, can produce flowers in various colors, including salmon, apricot, orange, red, pale pink, mauve, and white.

Scientific Name:Papaver orientale
Native Range:Turkey, Iran, and the Caucasus
Flowering Season:Late spring to early summer

33. Orthrosanthus chimboracensis (Morning Flag)

Orthrosanthus chimboracensis (Morning Flag) are beautiful types of flowers that start with the letter O

Orthorosanthus chimboracensis (commonly called morning flag) is a flowering plant belonging to the Iridaceae (iris) plant family. The plants are composed of sturdy, segmented stems and strap-like foliage. 

The flowers are produced in loose terminal clusters or individually. They have six ovate, pointed petals in shades that range from deep blue to periwinkle to white. Self-sowing morning flag plants produce several seeds and bloom in their second year of growth.

Scientific Name:Orthrosanthus chimboracensis
Native Range:Northwestern South America and parts of Central America
Flowering Season:August through November

34. Osbeckia


Commonly called osbeckia or starry osbeckia, Osbeckia stellata is an erect subshrub or herbaceous plant belonging to the Melastomataceae (melastomes) plant family. It features whorled, hairy leaves and singular, terminal flower blossoms with four bright-pink petals and a prominent cluster of central, yellow stamens. In its native habitat, it is most commonly found growing on grassy slopes at high altitudes.

Scientific Name:Osbeckia stellata
Native Range:Southern Asia
Flowering Season:July through November

35. Osier


A member of the Salicaceae (willow) plant family, Salix viminalis (commonly called osier, common osier, or basket willow) is a multistemmed shrub that can grow up to more than 30 feet in height but typically achieves around 20 feet. 

They produce long, slender, glossy green leaves and flowerheads throughout the branches. The yellow flowers have no petals and are called catkins. In the language of flowers, they represent frankness.

Scientific Name:Salix viminalis
Native Range:Europe and Asia
Flowering Season:April to May

36. Osmanthus fragrans (Sweet Olive)

Osmanthus fragrans (Sweet Olive)

A member of the Oleacea (olive) plant family, Osmanthus fragrans (commonly called osmanthus, sweet olive, fragrant olive, or tea olive) is a small evergreen shrub or tree. It has slender branches with elongated, ovate leaves. 

These flowers that start with the letter O are produced in clusters along the branches and consist of tiny flowers in shades of yellow, white, or orange. The flowers are commonly dried and used alone or blended with other leaves to make tea.

Scientific Name:Osmanthus fragrans
Native Range:Eastern Asia
Flowering Season:Mid-spring and late summer

37. Osmanthus heterophyllus (Holly Osmanthus)

Osmanthus heterophyllus (Holly Osmanthus)

Holly osmanthus is also a small, evergreen tree or shrub. It has slender branches. When young, the leaves have pointed margins and closely resemble the leaves of English holly (the popular Christmas plant). 

As the leaves mature, the edges smooth out and become simple oval shapes. Holly osmanthus produces clusters of small, fragrant flowers all along its branches. The flowers are typically snowy white and followed by black berries.

Scientific Name:Osmanthus heterophyllus
Native Range:Japan, Korea, and Taiwan
Flowering Season:Late fall through early winter

38. Our Lord’s Candle

Our Lord's Candle

A member of the Asparagaceae plant family, Hesperoyucca whipplei (commonly called our Lord’s candle, chaparral yucca, Spanish bayonet, foothills yucca, or Quixote yucca) is an evergreen desert shrub. It consists of a dense, three-foot rosette of sturdy, silvery green, lance-shaped foliage. 

When in bloom, an impressive, fourteen-foot stem arises from the center of the foliage to produce a large, terminal raceme of bell-shaped flowers in shades of purple and white.

Scientific Name:Hesperoyucca whipplei (formerly Yucca whipplei)
Native Range:California and coastal northwestern Mexico
Flowering Season:Mid-spring into summer

39. Outeniqua Yellowwood

Outeniqua Yellowwood

A member of the Podocarpaceae (podocarps) plant family, Afrocarpus falcatus is a large, evergreen, conifer tree that can grow to about 150 to 200 feet in height and six to seven feet in diameter. 

The female trees produce round, yellowish-green flowers that are actually seed-bearing cones. The trees produce strong wood that is commonly used in shipbuilding in addition to other types of construction. 

In English, the plant is called Outeniqua yellowwood, African pine tree, yellowwood, and weeping yew. It also has several common names in Afrikaans.

Scientific Name:Afrocarpus falcatus (Syn. Podocarpus falcatus)
Native Range:Southwestern coastal Africa
Flowering Season:Early summer

40. Ox-Eye Daisy

Ox-Eye Daisy

A member of the Asteraceae plant family, Leucanthemum vulgare is a freely spreading, rhizomatic perennial commonly called ox-eye daisy, dog daisy, or marguerite. 

These flowers that start with the letter O grow to about two feet in height and produce a profusion of cheerful-looking flowerheads composed of white ray florets surrounding bright-yellow disc florets. 

In the language of flowers, they symbolize both obstacles and patience.

Scientific Name:Leucanthemum vulgare
Native Range:Europe and northern Asia
Flowering Season:May through August

41. Oxalis


A member of the Oxalidaceae (wood sorrel) plant family, the Oxalis genus contains 566 species of annual and perennial flowering plants. The genus comprises plants commonly called wood sorrels, false shamrocks, and sourgrasses. They grow in clumps and produce various white, pink, purple, yellow, and red-accented flowers.

Scientific Name:Oxalis spp.
Native Range:Cosmopolitan
Flowering Season:Spring and summer

42. Oxlip


Primula elatior (commonly called oxlip or true oxlip) is an herbaceous or semi-evergreen perennial flower belonging to the Primulaceae (primrose) plan family. 

The plants produce low-growing rosettes of broad, ovate foliage and twelve-inch stems, upon which appear terminal clusters of nodding flowers in a pale shade of yellow. In the language of flowers, oxlip means “speak out.”

Scientific Name:Primula elatior
Native Range:Europe and northwestern Asia
Flowering Season:Mid-spring to early summer

43. Oxypetalum coeruleum (Tweedia)

Oxypetalum coeruleum (Tweedia)

A member of the Apocynaceae plant family, Oxypetalum coeruleum is an evergreen, perennial vine or straggling subshrub commonly called tweedia, which refers to a synonymous scientific name of the species. 

The plants produce heart-shaped, deep-green foliage and clusters of starry, sky-blue flowers that mature to purple. The Alba cultivar has white flowers, and ‘Rosea’ produces pink flowers.

Scientific Name:Oxypetalum coeruleum (Syn. Tweedia caerulea)
Native Range:Uruguay and southern Brazil
Flowering Season:Summer to fall

44. Oxyria digyna (Mountain Sorrel)

Oxyria digyna (Mountain Sorrel)

Oxyria digyna (commonly called mountain sorrel, alpine sorrel, or wood sorrel) is a perennial flowering plant species belonging to the Polygonaceae (buckwheat) plant family. 

They grow in dense bunches with kidney-shaped leaves and stalks that both tend to be reddish-green but can also be a deeper green in color. 

Mountain sorrels produce spike-shaped racemes of tiny flowers that emerge green and turn red as they mature. In the language of flowers, sorrel represents affection, maternal tenderness, and joy.

Scientific Name:Oxyria digyna
Native Range:Mountainous and arctic regions of the Northern Hemisphere
Flowering Season:June through September

45. Oyster Plant

Oyster Plant

A member of the Boraginaceae plant family, Mertensia maritima (commonly called oyster plant, oyster leaf, or sea bluebells) is a low-growing, spreading perennial that produces thick, oval-shaped leaves in a cool shade of blue-green. 

The deep indigo-blue flowers appear in clusters, are bell-shaped, and have dark purple centers. The plant reportedly tastes faintly of oysters when eaten, and this is where its common names come from.

Scientific Name:Mertensia maritima
Native Range:Northern gravelly coastal regions of the Northern Hemisphere
Flowering Season:Late spring to midsummer

46. Ozark Bluestar

Ozark Bluestar

Amsonia illustris (commonly called Ozark bluestar, showy blue-star, or swamp blue-star) is a perennial, clump-forming herb that belongs to the Apocynaceae plant family. 

The plants have clusters of leafy stems that grow to be about two to three feet in height. They produce terminal, pyramid-shaped clusters of star-shaped flowers with narrow petals in light shades of blue. The flowers attract native butterflies.

Scientific Name:Amsonia illustris
Native Range:Iowa, Missouri, Kansas, Texas, and Nevada
Flowering Season:March through May

47. Ozark Hawthorn

Ozark Hawthorn are beautiful types of flowers that start with the letter O

Crataegus alabamensis (commonly called Ozark hawthorn) is an endangered, deciduous, perennial shrub or tree that belongs to the Rosaceae (rose) plant family. 

The plants are quite attractive when they bloom during spring, as the trees or shrubs become covered with profusions of flower clusters. The flowers have rounded, five-petaled flowers that resemble wild roses, and they blossom in shades of snowy white or light pink. 

In the language of flowers, hawthorn symbolizes prudence and hope.

Scientific Name:Crataegus alabamensis (Syn. Crataegus insidiosa)
Native Range:Southeastern United States
Flowering Season:March and April

48. Ozark Sundrops

Ozark Sundrops

Oenothera macrocarpa is an herbaceous perennial that belongs to the Onagraceae plant family. Common names include Ozark sundrops, bigfruit evening primrose, and Missouri evening primrose. 

The plants can grow to be about 18 inches in height and spread about two feet. They produce several canary-yellow, cup-shaped, lightly fragrant flowers throughout the blooming season. Flowers open in the evening, last through the night, and are spent and closed by morning.

Scientific Name:Oenothera macrocarpa (Syn. Oenothera missouriensis)
Native Range:South-central United States and northern Mexico
Flowering Season:April through August

49. Ozark Witch-Hazel

Ozark Witch-Hazel

A member of the Hamamelidaceae (witch-hazel) plant family, Hamamelis vernalis (commonly called Ozark witch-hazel or vernal witch-hazel) is a large, deciduous shrub or small tree that reaches about 15 feet in height. 

The shrubs have an open, fanned crown with irregular, crooked branches. The leaves are crinkled and narrowed, and the flowers appear on bare branches and are slightly star-shaped with wrinkled petals and calyces in shades of yellow, orange, and dark red. 

Witch-hazel represents a spell or being spellbound in the language of flowers.

Scientific Name:Hamamelis vernalis
Native Range:Oklahoma, Missouri, and Arkansas
Flowering Season:December through March

50. Ozothamnus diosmifolius (Rice Flower)

Ozothamnus diosmifolius (Rice Flower)

Ozothamnus diosmifolius is an erect, perennial, woody shrub that grows to be about seven feet in height. Its common names include rice flower, pill flower, sago bush, and white dogwood. Although, it belongs to the Asteraceae plant family, not the Cornaceae (dogwood) plant family. 

The rice flower plant produces flower clusters similar to those of dogwoods, as their clusters feature dense corymbs of white flowerheads. They are widely commercially grown, as rice flowers are popular in the florist trade.

Scientific Name:Ozothamnus diosmifolius
Native Range:Eastern Australia
Flowering Season:Mid-spring to mid-fall

Flowers That Start With O FAQs:

What Are Some Popular Pink Flowers That Start With O?

Several species of primrose from the Oenothera genus have pink flowers, in addition to oleanders, several species of orchids, and Oriental lilies.

What Are Some Popular Red Flowers Beginning With O?

Some popular red flowers that start with the letter O include several species of orchids, osteospermum, and oleanders, in addition to Oriental lilies and Oriental poppies.

What Are Some Unique Flowers That Start With O?

A few unique plants with unusual-looking flower blossoms that start with the letter O include old man’s whiskers, old man’s beard, one-flowered wintergreen, orange ball tree, orange milkwort, and our Lord’s candle.

Are There Any Rare or Endangered Flowers That Start With O?

Some endangered flowers that start with the letter O include:

  • Ochrosia haleakalae (Holei)
  • Ochrosia kilaueaensis (Holei)
  • Oenothera deltoides ssp. howellii (Antioch dunes evening primrose)
  • Opuntia treleasei (Bakersfield cactus)
  • Orcuttia spp. (various species of Orcutt grass)
  • Ottoschulzia rhodoxylon (Palo de rosa)
  • Oxypolis canbyi (Canby’s dropwort)
  • Oxytheca parishii var. goodmaniana (Cushenbury oxytheca)
  • Oxytropis campestris var. chartacea (Fassett’s locoweed)

It’s Official! Flowers That Start With O Are Totally Oneiric

Aren’t flowers that start with O dreamy? We certainly think so! Whether you plant all O flowers or the entire alphabet, your garden is sure to be dreamy too!

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