| Chaenomeles speciosa | Flowering Quince | | Dogwood & Common Shrubs | Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Zone 5a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Chamaecyparis nootkatensis ( Calitropsis nootkatensis, Xanthocyparis nootkatensis) | Alaska Cedar; Nootka Falsecypress; Yellow Cypress | | Evergreens with Scales | Tree > 30 feet, Evergreen, Full sun, Part shade, Zone 4a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Chamaecyparis obtusa | Hinoki Falsecypress | | Evergreens with Scales | Tree > 30 feet, Tree < 30 feet, Evergreen, Full sun, Part shade, Zone 5a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Chamaecyparis pisifera | Japanese or Sawara Falsecypress | | Evergreens with Scales | Tree > 30 feet, Shrub 4 to 8 feet, Evergreen, Full sun, Part shade, Zone 5a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Chamaecyparis thyoides | Atlantic White Cedar; Whitecedar Falsecypress | | | Tree > 30 feet, Tree < 30 feet, Evergreen, Full sun, Zone 5a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Chionanthus virginicus | Fringetree; Old-man's-beard | | Low pH | Tree < 30 feet, Shrub > 8 feet, Deciduous, Full sun, Part shade, Zone 5a, Requires acid (pH 5.0 to 7.0), Tolerates salty soil |
| Cladrastis kentukea | Yellowwood | | High pH | Tree > 30 feet, Deciduous, Full sun, Zone 4b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Clematis spp. | Clematis | | | Vine, Deciduous, Full sun, Part shade, Zone 4a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Clethra alnifolia | Summer Sweet Clethra | | Low pH | Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Zone 4b, Requires acid (pH 5.0 to 7.0), Tolerates salt spray |
| Clethra barbinervis | Japanese Clethra | | | Tree < 30 feet, Shrub > 8 feet, Deciduous, Full sun, Part shade, Zone 5b, Requires acid (pH 5.0 to 7.0) |
| Comptonia peregrina | Sweetfern | | | Shrub < 4 feet, Groundcover, Deciduous, Full sun, Part shade, Zone 3a, Requires acid (pH 5.0 to 7.0), Tolerates salt spray |
| Cornus alternifolia | Pagoda Dogwood | | | Tree < 30 feet, Deciduous, Part shade, Shade, Zone 4a, Requires acid (pH 5.0 to 7.0) |
| Cornus amomum | Silky Dogwood | | None Listed | Shrub > 8 feet, Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Shade, Zone 4a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Cornus florida | Flowering Dogwood | | Cornus, Viburnum, and Friends - Winter Identification; Dogwood & Common Shrubs | Tree < 30 feet, Deciduous, Part shade, Zone 5b, Requires acid (pH 5.0 to 7.0) |
| Cornus kousa | Kousa Dogwood | | Cornus, Viburnum, and Friends - Winter Identification, Dogwood & Common Shrubs; Cornus, Viburnum, and Friends - Winter Identification; Dogwood & Common Shrubs | Tree < 30 feet, Deciduous, Full sun, Part shade, Zone 5a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Cornus mas | Corneliancherry Dogwood; Cornelian Cherry | | Cornus, Viburnum, and Friends - Winter Identification, Dogwood & Common Shrubs; Dogwood & Common Shrubs | Tree < 30 feet, Deciduous, Full sun, Part shade, Zone 5a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Cornus racemosa | Gray Dogwood | | Dogwood & Common Shrubs | Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Zone 3b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Cornus sanguinea | Bloodtwig Dogwood | | Dogwood & Common Shrubs | Shrub > 8 feet, Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Zone 5a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Cornus sericea or alba | Red Twig Dogwood; Redosier Dogwood; Tatarian Dogwood | | Cornus, Viburnum, and Friends - Winter Identification, Dogwood & Common Shrubs; Cornus, Viburnum, and Friends - Winter Identification; Dogwood & Common Shrubs | Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Zone 3a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0), Tolerates salt spray |
| Corylopsis spicata | Spike Winterhazel | | Low pH | Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Zone 5a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |