Plants That Start With O

24 plants Animals and nature Checked 9 Oct 2026

Here are 24 plants that start with O, each with a one-line description so you can tell what it is. The best-known ones come first, then the full list in A to Z order.

O has 24 plants and opens with everyday food. Orange, olive, oat, onion, okra and oregano are all here, which makes O friendly for children. Oak is the standout tree, listed both as oak and oak tree.

Further down, the names grow stranger. Oca is a South American plant grown for its edible tubers, and the oyster plant is a Mediterranean herb with purple flower heads. The obedience plant and the orchid tree are good surprises. Several entries begin with oriental, such as oriental plane and oriental spruce.

Plants starting with O: 24
Best known: orange, oak
Longest name: oriental bittersweet

Best-known plants that start with O

The ones most people will recognise, good for school lists, quizzes and games.

orange
oak
olive
orange tree
oat
oregano
oil palm
oak tree
okra
olive tree
oleander
onion

All plants that start with O

#	Name	What it is
1	oak	a deciduous tree of the genus Quercus; has acorns and lobed leaves
2	oak fern	bright blue-green fern widely distributed especially in damp acid woodlands of temperate northern hemisphere
3	oak tree	a deciduous tree of the genus Quercus; has acorns and lobed leaves
4	oat	annual grass of Europe and North Africa; grains used as food and fodder (referred to primarily in the plural: `oats')
5	obedience plant	white-flowered West Indian plant whose root yields arrowroot starch
6	oca	South American wood sorrel cultivated for its edible tubers
7	oil palm	pinnate-leaved palms of the genus Elaeis having dense clusters of crowded flowers and bright red fruit and yielding...
8	okra	tall coarse annual of Old World tropics widely cultivated in southern United States and West Indies for its long...
9	oleander	evergreen shrub with showy pink, red or white flowers
10	olive	evergreen tree cultivated in the Mediterranean region since antiquity and now elsewhere; has edible shiny black fruits
11	olive tree	a tree of the genus Olea cultivated for its fruit
12	onion	plant grown for its strong-flavored edible bulb
13	orange	any citrus tree bearing oranges
14	orange grass	annual wiry-stemmed North American weed with minute scalelike leaves and small yellow flowers
15	orange tree	any citrus tree bearing oranges
16	orchard grass	widely grown stout Old World hay and pasture grass
17	orchid cactus	any cactus of the genus Epiphyllum having flattened jointed irregularly branching stems and showy tubular flowers
18	orchid tree	small East Indian tree having orchid-like flowers and hard dark wood
19	oregano	aromatic Eurasian perennial
20	oriental bittersweet	ornamental Asiatic vine with showy orange-yellow fruit with a scarlet aril; naturalized in North America
21	oriental cherry	ornamental tree with inedible fruits widely cultivated in many varieties for its white blossoms
22	oriental plane	large tree of southeastern Europe to Asia Minor
23	oriental spruce	evergreen tree of the Caucasus and Asia Minor used as an ornamental having pendulous branchlets
24	oyster plant	Mediterranean biennial herb with long-stemmed heads of purple ray flowers and milky sap and long edible root

Short plants with O

oak
olive
oat
okra
onion
oca

Questions people ask

How many plants start with O?

This list has 24 plants starting with O, from well-known ones like orange, oak, olive to rarer kinds.

What plants start with O?

Well-known examples are orange, oak, olive, orange tree, oat, oregano, oil palm, oak tree.

Source: Princeton WordNet, a public dictionary database, reviewed by our editors to keep only clear, real members of the list. Meanings are short dictionary glosses.

See every letter on one page: plants A to Z