Flowers that Start with O

Flowers that start with the letter “O” might not be as well-known as roses or daisies, but they are just as interesting and beautiful! From the bright and cheerful Osteospermum to the sweet-smelling Osmanthus, these flowers come in all kinds of colors, shapes, and sizes. Some grow in the wild, while others are favorites in gardens around the world. In this post, we’ll take a closer look at some cool flowers that begin with “O.” You’ll learn their scientific names, where they grow, how to take care of them, and a few fun facts along the way. Get ready to explore the world of “O” flowers—you might just find a new favorite!

Here Is A List Of Flowers That Start With O

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Ocotillo

Scientific name: Fouquieria splendens
Type of flower: Shrub (woody perennial)
Habitat: Desert regions of the southwestern United States and northern Mexico
Colors: Bright red, orange-red
Blooming season: Spring to early summer, especially after rain
Growth conditions and growing zones: Thrives in dry, rocky soils; full sun; USDA zones 8–11
Cultural significance: Used by Indigenous peoples for fencing and medicine
Interesting fact: Though it looks like a cactus, it’s actually not! Ocotillo leaves fall off during dry spells and reappear quickly after rain.

Olearia

Scientific name: Olearia phlogopappa (one common variety)
Type of flower: Shrub
Habitat: Native to Australia, especially in alpine and coastal regions
Colors: White, pale purple, pink
Blooming season: Spring to summer
Growth conditions and growing zones: Prefers well-drained soil and full sun to part shade; USDA zones 8–10
Cultural significance: Grown in ornamental gardens in Australia
Interesting fact: Often called the “daisy bush” because its flowers resemble daisies.

Oncidium Orchid

Scientific name: Oncidium spp.
Type of flower: Orchid
Habitat: Tropical and subtropical regions of Central and South America
Colors: Yellow, brown, red, pink, white
Blooming season: Varies by species; often fall to spring
Growth conditions and growing zones: Prefers humid, warm conditions and indirect light; USDA zones 9–11 (greenhouse or indoor growing)
Cultural significance: Popular among orchid collectors; often called the “dancing lady” orchid
Interesting fact: The petals look like tiny dancers in skirts, especially when swaying in the breeze!

Opium Poppy

Scientific name: Papaver somniferum
Type of flower: Annual
Habitat: Originally from the Mediterranean region, now grown in many temperate zones
Colors: Red, purple, pink, white
Blooming season: Late spring to early summer
Growth conditions and growing zones: Prefers full sun and well-drained soil; USDA zones 3–9
Cultural significance: Used historically for medicinal and ceremonial purposes; seeds used in baking
Interesting fact: While the seeds are safe to eat, the sap from the plant is used to make powerful medicines (and is also the source of the drug opium).

Orange Blossom

Scientific name: Citrus sinensis (sweet orange)
Type of flower: Flowering tree
Habitat: Subtropical to tropical regions
Colors: White
Blooming season: Spring
Growth conditions and growing zones: Needs full sun and well-drained soil; USDA zones 9–11
Cultural significance: Symbol of purity and good fortune; used in perfumes and wedding traditions
Interesting fact: Orange blossoms are so fragrant that entire orchards can fill the air with a sweet, citrusy scent.

Orange Trumpet Creeper

Scientific name: Pyrostegia venusta
Type of flower: Climbing vine (perennial)
Habitat: Native to South America; commonly found in tropical and subtropical areas
Colors: Bright orange
Blooming season: Winter to early spring
Growth conditions and growing zones: Prefers full sun and well-drained soil; USDA zones 9–11
Cultural significance: Often grown on trellises or walls for its vibrant color
Interesting fact: This plant attracts hummingbirds and butterflies with its bright, tubular flowers.

Orchid

Scientific name: Orchidaceae (family of over 25,000 species)
Type of flower: Perennial (many are epiphytes)
Habitat: Found on every continent except Antarctica; most diverse in tropical rainforests
Colors: Almost every color—white, pink, purple, blue, yellow, red, green
Blooming season: Varies by species, many bloom annually or twice a year
Growth conditions and growing zones: Thrive in humid environments with indirect light; USDA zones 9–12 or as indoor plants
Cultural significance: Symbolizes beauty, love, and strength; prized in many cultures for their exotic appearance
Interesting fact: Orchids can grow on trees without harming them—they’re just hitching a ride!

Orlaya

Scientific name: Orlaya grandiflora
Type of flower: Annual
Habitat: Native to Europe and the Mediterranean
Colors: White
Blooming season: Late spring to early summer
Growth conditions and growing zones: Prefers full sun and well-drained soil; USDA zones 3–9
Cultural significance: Popular in cottage gardens and floral arrangements
Interesting fact: Its delicate, lace-like flowers make it a favorite among pollinators like bees and butterflies.

Ornamental Kale

Scientific name: Brassica oleracea (var. acephala)
Type of flower: Technically a leafy plant, not a true flower, but grown for decorative purposes
Habitat: Cultivated in gardens around the world
Colors: Purple, pink, white, and green
Blooming season: Fall and winter
Growth conditions and growing zones: Prefers cool weather and full sun; USDA zones 2–11
Cultural significance: Adds color to winter gardens and is edible (though not very tasty!)
Interesting fact: The colorful “petals” are actually leaves—true flowers may appear if left to bolt.

Ornamental Onion

Scientific name: Allium giganteum (one common type)
Type of flower: Perennial bulb
Habitat: Native to Central and Southwest Asia
Colors: Purple, pink, white
Blooming season: Late spring to early summer
Growth conditions and growing zones: Prefers full sun and well-drained soil; USDA zones 4–9
Cultural significance: Popular in landscape design for its striking globe-like flower heads
Interesting fact: Related to edible onions and garlic—if you crush a leaf, you’ll smell it!

Ornithogalum

Scientific name: Ornithogalum umbellatum
Type of flower: Perennial bulb
Habitat: Native to Europe and the Mediterranean; naturalized in parts of North America
Colors: White with green stripes
Blooming season: Late spring
Growth conditions and growing zones: Thrives in full sun to partial shade; USDA zones 4–9
Cultural significance: Often called “Star of Bethlehem” because of its star-shaped blossoms
Interesting fact: Although beautiful, it can be invasive in some areas and mildly toxic to pets.

Osmanthus

Scientific name: Osmanthus fragrans
Type of flower: Evergreen shrub or small tree
Habitat: Native to Asia, especially China, Japan, and the Himalayas
Colors: White, pale yellow, orange
Blooming season: Fall (some varieties bloom in spring or summer)
Growth conditions and growing zones: Prefers full sun to partial shade; USDA zones 7–10
Cultural significance: In Chinese culture, osmanthus symbolizes love and romance; the flowers are used in tea and desserts
Interesting fact: Despite their small size, osmanthus flowers are incredibly fragrant and can scent an entire garden!

Osteospermum

Scientific name: Osteospermum ecklonis
Type of flower: Perennial (often grown as an annual)
Habitat: Native to South Africa
Colors: Purple, pink, white, yellow, orange
Blooming season: Spring through fall
Growth conditions and growing zones: Prefers full sun and well-drained soil; USDA zones 9–11
Cultural significance: Also called “African Daisy”; popular in containers and sunny flower beds
Interesting fact: The center of the flower often has a blue or purple eye, adding to its striking appearance.

Oxalis

Scientific name: Oxalis spp.
Type of flower: Perennial or annual, depending on species
Habitat: Found in many regions worldwide, including the Americas, Africa, and Europe
Colors: Pink, yellow, white, purple
Blooming season: Spring to fall (depending on species and climate)
Growth conditions and growing zones: Prefers well-drained soil and part shade; USDA zones 3–10
Cultural significance: Often associated with good luck, especially the varieties with three- or four-leaf clover-like foliage
Interesting fact: Some species close their flowers and leaves at night or on cloudy days—this is called “nyctinasty”!

Oxeye Daisy

Scientific name: Leucanthemum vulgare
Type of flower: Perennial wildflower
Habitat: Native to Europe and Asia; widespread in North America
Colors: White petals with yellow centers
Blooming season: Late spring to early fall
Growth conditions and growing zones: Grows in sunny meadows and roadsides; USDA zones 3–8
Cultural significance: Symbol of innocence and purity; often used in wildflower gardens
Interesting fact: Though pretty, it can be invasive in pastures and displace native plants.

Oxlip

Scientific name: Primula elatior
Type of flower: Perennial
Habitat: Native to Europe; grows in damp meadows and woodlands
Colors: Pale yellow
Blooming season: Early to mid-spring
Growth conditions and growing zones: Prefers moist, well-drained soil and partial shade; USDA zones 4–8
Cultural significance: One of the first flowers to bloom in spring, often associated with renewal and rebirth
Interesting fact: Closely related to the primrose, the oxlip can hybridize with other Primula species in the wild.

Ozothamnus

Scientific name: Ozothamnus diosmifolius
Type of flower: Shrub
Habitat: Native to Australia; grows in dry forests and open woodlands
Colors: White, pale pink
Blooming season: Late spring to summer
Growth conditions and growing zones: Likes well-drained soil and full sun; USDA zones 9–11
Cultural significance: Used in the floral industry, especially in dried flower arrangements
Interesting fact: Also called “Rice Flower” due to its tiny clustered blossoms that resemble grains of rice.

Orychophragmus

Scientific name: Orychophragmus violaceus
Type of flower: Annual or biennial
Habitat: Native to China; grows in fields and along roadsides
Colors: Lavender, purple, pink
Blooming season: Early to mid-spring
Growth conditions and growing zones: Prefers full sun to light shade and moist soil; USDA zones 6–9
Cultural significance: Commonly grown in Chinese gardens for its spring color
Interesting fact: Sometimes called “Chinese Violet Cress,” this flower is part of the mustard family.

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