Al
- Alcea
- X Alcea pallida — pale hollyhock
- X Alcea rosea — hollyhock
- Alchemilla
- X Alchemilla filicaulis — thin-stemmed lady's-mantle
- X Alchemilla monticola — hairy lady's-mantle
- Aletris
- N Aletris farinosa — colicroot Threatened
- Alisma
- N Alisma gramineum — grass-leaved water-plantain
- N Alisma subcordatum — southern water-plantain
- N Alisma triviale — northern water-plantain
- Alliaria
- X Alliaria petiolata — garlic mustard, hedge garlic
- Allium
- N Allium burdickii — narrow-leaved wild leek
- N Allium canadense — Canada wild onion, meadow garlic, meadow onion
- N Allium cernuum — nodding onion
- X Allium oleraceum — wild garlic
- X Allium sativum — garlic
- X Allium schoenoprasum var. schoenoprasum — chives
- N Allium schoenoprasum var. sibiricum — Siberian chives
- N Allium stellatum — prairie onion, wild onion
- N Allium tricoccum — wild leek, small wild leek, ramps
- X Allium vineale — field garlic
- Alnus
- X Alnus glutinosa — black alder, European alder
- N Alnus incana — grey alder, white alder, hoary alder, speckled alder
- N Alnus viridis — green alder, mountain alder, American green alder, Siberian alder, Sitka alder
- Alopecurus
- N Alopecurus aequalis — shortawn foxtail
- N Alopecurus alpinus — alpine foxtail
- X Alopecurus geniculatus — water foxtail
- X Alopecurus pratensis — meadow foxtail
- Althaea
- X Althaea hirsuta — hairy marsh-mallow
- X Althaea officinalis — common marsh-mallow
- Alyssum
- X Alyssum alyssoides — pale alyssum, small alyssum, yellow alyssum, pale madwort
- X Alyssum murale — yellow-tuft
Read more about this topic: List Of Canadian Plants By Genus