- Absinthe wormwood
- African Coromandel
- African tulip tree
- Agarita
- Air potato
- Akeake
- Alamo vine
- Alder buckthorn
- Aleppo pine
- Alexanders
- Alfalfa
- Alkali heliotrope
- Allegheny blackberry
- Allegheny monkeyflower
- Alligatorweed
- Almond
- Alpine Aster
- Alpine azalea
- Alpine bistort
- Alpine Enchanter's-nightshade
- Alpine sorrel
- Alpine Squill
- Alsike clover
- Alternate-leaved dogwood
- Alternate-leaved Golden Saxifrage
- American basketflower
- American beautyberry
- American beech
- American bistort
- American black elderberry
- American black nightshade
- American bladdernut
- American brooklime
- American burnweed
- American cancer-root
- American century plant
- American chestnut
- American elm
- American field pansy
- American fly-honeysuckle
- American germander
- American groundnut
- American hazelnut
- American hog-peanut
- American holly
- American hophornbeam
- American hornbeam
- American jumpseed
- American lopseed
- American lotus
- American Mistletoe
- American parsley fern
- American persimmon
- American plantain
- American pokeweed
- American Royal Fern
- American searocket
- American spikenard
- American sweetgum
- American sycamore
- American trailplant
- American trumpet vine
- American tuliptree
- American vetch
- American water-willow
- American white waterlily
- American wild carrot
- American wintergreen
- American witch-hazel
- Amur honeysuckle
- Anacua
- Angled lobelia
- Aniseroot
- Annual bastard cabbage
- Annual fleabane
- Annual Honesty
- Annual Meadow-grass
- Annual mercury
- Antelope Bitterbrush
- Antelopehorn Milkweed
- Apache plume
- Apple
- Apricot globemallow
- Arabian pea
- Arctic Butterbur
- Arctic raspberry
- Arctic Starflower
- Armenian Blackberry
- Arrow-leaved tearthumb
- Arrowhead
- Arrowleaf balsamroot
- Arrowleaf Senecio
- Arroyo lupine
- Artichoke Thistle
- Artillery Plant
- Asarabacca
- Ashe juniper
- Asian bittersweet
- Asian mazus
- Asian Taro
- Asiatic dayflower
- Asthma Plant
- Austral Bracken
- Australian Blackthorn
- Australian Cheesewood
- Australian Umbrella Tree
- Autumn clematis
- Autumn Crocus
- Autumn Hawkbit
- Autumn olive
- Azure bluet