Alabama flower:
Alabama wildflower:

camellia
oak-leaf hydrangea

Alaska flower:

forget-me-not

Arizona flower:

saguaro cactus blossom

Arkansas flower:

apple blossom

California flower:
California grass:

California poppy
purple needlegrass

Colorado flower:
Colorado grass:

Rocky Mt. columbine
blue grama grass

Connecticut flower:

mountain laurel

Delaware flower:

peach blossom

Florida flower:
Florida wildflower:

orange blossom
coreopsis

Georgia flower:
Georgia wildflower:

Cherokee rose
azalea

Hawaii flower:
 
Hawaiian Island flowers:
  
           - Hawai'i:
           - Maui:
           - O'ahu:
           - Kaua'i:
           - Moloka'i:
           - Lana'i:
           - Ni'ihau:
           - Kaho'olawe:

pua aloalo - yellow hibiscus
 
 
 
red pua lehua ('Ohi'a blossom)
lokelani (Rosa damascena)
pua 'Illima (Sida fallax)
mokihana (berry of native citrus)
pua kukui (blossom of candlenut tree)
kauna'oa (native dodder)
pupu (small shells)
hinahina (native beach heliotrope)
 

Idaho flower:

syringa (mock orange)

Illinois flower:
Illinois grass:

purple violet
big bluestem

Indiana flower:

peony

Iowa flower:

wild prairie rose

Kansas flower:

sunflower

Kentucky flower:

goldenrod

Louisiana flower:

magnolia

Maine flower*:

eastern white pine tassel & cone*

Maryland flower:

black-eyed Susan

Massachusetts flower:

mayflower

Michigan flower:
Michigan wildflower:

apple blossom
dwarf lake iris

Minnesota flower:

pink and white ladyslipper

Mississippi flower:

magnolia

Missouri flower:

hawthorn

Montana flower:
Montana grass:

bitterroot
bluebunch wheatgrass

Nebraska flower:
Nebraska grass:

goldenrod
little bluestem

Nevada flower:
Nevada grass:

sagebrush
Indian rice grass

New Hampshire flower:
New Hampshire wildflower:

purple lilac
pink lady's slipper

New Jersey flower:

violet

New Mexico flower:
New Mexico grass:

yucca
blue grama grass

New York flower:
New York bush:

rose
Lilac bush (Syringa vulgaris)

North Carolina flower:
North Carolina carn. plant
North Carolina wildflower:

American dogwood
Venus fly trap
Carolina lily

North Dakota state flower:
North Dakota state grass:

wild prairie rose
western wheatgrass

Ohio state flower:
Ohio state wildflower:

scarlet carnation
white trillium

Oklahoma flower:
Oklahoma floral emblem**:
Oklahoma grass:
Oklahoma wildflower:

Oklahoma rose
mistletoe**
Indiangrass
Indian Blanket

Oregon flower:

Oregon grape

Pennsylvania flower:
Pennsylvania plant:

mountain laurel
Penngift Crownvetch

Rhode Island flower:

violet

South Carolina flower:
South Carolina grass:

Carolina Jessamine
Indian grass

South Dakota flower:
South Dakota grass:

pasque flower
western wheat grass

Tennessee flower:

iris

Texas flower:
Texas plant:
Texas shrub:
Texas native shrub:

Texas bluebonnet
prickly pear cactus
crape myrtle
Texas purple sage

Utah flower:
Utah grass:

sego lily
Indian ricegrass

Vermont flower:

red clover

Virginia flower:

flowering dogwood

Washington flower:
Washington grass:

coast rhododendron
bluebunch wheatgrass

West Virginia flower:

rhododendron

Wisconsin flower:

wood violet

Wyoming flower:
Wyoming grass:

Indian paintbrush
western wheatgrass

*

Maine's state "flower" - botanically, the white pine cone and tassel are not considered flowers since gymnosperms do not have true flowers. The reproductive structures of pines are known as strobili. You could accurately state that Maine is the only state to have an official state strobilae.

**

Oklahoma's state "flower" - mistletoe is a plant, not a flower (it does bear true flowers, but they are not showy).

Source: United States Arboretum