Quick answer: 33 native Pennsylvania plants have a recorded bloom range that includes March.
33 species
- American holly Ilex opaca · 24 states
- American hornbeam Carpinus caroliniana · 29 states
- Atlantic white cedar Chamaecyparis thyoides · 12 states
- Black ash Fraxinus nigra · 10 states
- Black cherry Prunus serotina · 32 states
- Bur oak Quercus macrocarpa · 24 states
- Canada wild rye Elymus canadensis · 18 states
- Carolina springbeauty Claytonia caroliniana · 8 states
- Chinkapin oak Quercus muehlenbergii · 14 states
- Creeping phlox Phlox subulata · 11 states
- Eastern red cedar Juniperus virginiana · 36 states
- Eastern red columbine Aquilegia canadensis · 36 states
- Eastern redbud Cercis canadensis · 30 states
- Flowering dogwood Cornus florida · 22 states
- Mayapple Podophyllum peltatum · 18 states
- New Jersey tea Ceanothus americanus · 31 states
- Northern red oak Quercus rubra · 24 states
- Ohio buckeye Aesculus glabra · 12 states
- Pin oak Quercus palustris · 18 states
- Pitch pine Pinus rigida · 12 states
- Post oak Quercus stellata · 9 states
- Quaking aspen Populus tremuloides · 24 states
- Red maple Acer rubrum · 30 states
- Red pine Pinus resinosa · 13 states
- River birch Betula nigra · 23 states
- Sassafras Sassafras albidum · 22 states
- Scarlet oak Quercus coccinea · 17 states
- Shagbark hickory Carya ovata · 22 states
- Shortleaf pine Pinus echinata · 9 states
- Sweetgum Liquidambar styraciflua · 22 states
- Virginia springbeauty Claytonia virginica · 10 states
- White oak Quercus alba · 33 states
- Wild blue Phlox divaricata · 32 states