Quick answer: 192 native Pennsylvania plants have a recorded bloom range that includes May.
192 species
- Adam's needle Yucca filamentosa · 21 states
- Allegheny chinquapin Castanea pumila · 21 states
- Allegheny serviceberry Amelanchier laevis · 17 states
- American alumroot Heuchera americana · 20 states
- American basswood Tilia americana · 37 states
- American beech Fagus grandifolia · 31 states
- American bittersweet Celastrus scandens · 33 states
- American bladdernut Staphylea trifolia · 28 states
- American cranberry Vaccinium macrocarpon · 15 states
- American hazelnut Corylus americana · 34 states
- American holly Ilex opaca · 28 states
- American hornbeam Carpinus caroliniana · 33 states
- American mountain ash Sorbus americana · 18 states
- American plum Prunus americana · 37 states
- American strawberry bush Euonymus americanus · 23 states
- Appalachian gooseberry Ribes rotundifolium · 11 states
- Atlantic white cedar Chamaecyparis thyoides · 17 states
- Balsam poplar Populus balsamifera · 8 states
- Bear oak Quercus ilicifolia · 13 states
- Bearberry Arctostaphylos uva-ursi · 34 states
- Bebb willow Salix bebbiana · 6 states
- Birdfoot violet Viola pedata · 34 states
- Black cherry Prunus serotina · 35 states
- Black huckleberry Gaylussacia baccata · 25 states
- Black locust Robinia pseudoacacia · 12 states
- Black maple Acer nigrum · 3 states
- Black oak Quercus velutina · 30 states
- Black tupelo Nyssa sylvatica · 31 states
- Black walnut Juglans nigra · 33 states
- Black willow Salix nigra · 24 states
- Blackjack oak Quercus marilandica · 24 states
- Blue wild indigo Baptisia australis · 23 states
- Bluebead Clintonia borealis · 14 states
- Bog Labrador tea Ledum groenlandicum · 11 states
- Bog laurel Kalmia polifolia · 13 states
- Box huckleberry Gaylussacia brachycera · 8 states
- Broadleaf cattail Typha latifolia · 39 states
- Bunchberry Cornus canadensis · 18 states
- Bur oak Quercus macrocarpa · 33 states
- Butterflyweed Asclepias tuberosa · 40 states
- Butternut Juglans cinerea · 26 states
- Canada anemone Anemone canadensis · 29 states
- Canada wild rye Elymus canadensis · 37 states
- Canada yew Taxus canadensis · 18 states
- Canadian serviceberry Amelanchier canadensis · 21 states
- Canadian wild ginger Asarum canadense · 30 states
- Candle anemone (thimbleweed) Anemone cylindrica · 12 states
- Cardinal flower Lobelia cardinalis · 41 states
- Carolina allspice Calycanthus floridus · 17 states
- Carolina springbeauty Claytonia caroliniana · 20 states
- Chinkapin oak Quercus muehlenbergii · 30 states
- Chokecherry Prunus virginiana · 44 states
- Cinnamon fern Osmunda cinnamomea · 32 states
- Climbing prairie rose Rosa setigera · 27 states
- Cockspur hawthorn Crataegus crus-galli · 25 states
- Common blue violet Viola sororia · 37 states
- Common elderberry Sambucus nigra ssp. canadensis · 36 states
- Common hackberry Celtis occidentalis · 33 states
- Common hoptree Ptelea trifoliata · 28 states
- Common leopardbane Arnica acaulis · 10 states
- Common ninebark Physocarpus opulifolius · 30 states
- Common persimmon Diospyros virginiana · 26 states
- Common selfheal Prunella vulgaris · 25 states
- Common winterberry Ilex verticillata · 32 states
- Common yarrow Achillea millefolium · 47 states
- Coralberry Symphoricarpos orbiculatus · 30 states
- Creeping phlox Phlox stolonifera · 11 states
- Creeping phlox Phlox subulata · 23 states
- Creeping snowberry Gaultheria hispidula · 12 states
- Cucumbertree Magnolia acuminata · 19 states
- Deerberry Vaccinium stamineum · 22 states
- Downy hawthorn Crataegus mollis · 24 states
- Downy serviceberry Amelanchier arborea · 37 states
- Dutchman's breeches Dicentra cucullaria · 32 states
- Dwarf crested iris Iris cristata · 17 states
- Dwarf larkspur Delphinium tricorne · 15 states
- Early azalea Rhododendron prinophyllum · 17 states
- Eastern hop-hornbeam Ostrya virginiana · 37 states
- Eastern leatherwood Dirca palustris · 25 states
- Eastern purple coneflower Echinacea purpurea · 24 states
- Eastern red cedar Juniperus virginiana · 37 states
- Eastern red columbine Aquilegia canadensis · 36 states
- Eastern redbud Cercis canadensis · 32 states
- Eastern smooth beardtongue Penstemon laevigatus · 15 states
- Eastern white pine Pinus strobus · 28 states
- Fire pink Silene virginica · 26 states
- Flame azalea Rhododendron calendulaceum · 14 states
- Flowering dogwood Cornus florida · 31 states
- Foxglove beardtongue Penstemon digitalis · 35 states
- Fragrant sumac Rhus aromatica · 30 states
- Golden alexanders Zizia aurea · 35 states
- Gray alder Alnus incana · 26 states
- Gray dogwood Cornus racemosa · 19 states
- Grayhead coneflower Ratibida pinnata · 26 states
- Green ash Fraxinus pennsylvanica · 43 states
- Green-and-gold Chrysogonum virginianum · 13 states
- Heart-leaved meadow parsnip Zizia aptera · 30 states
- Heartleaf foamflower Tiarella cordifolia · 18 states
- Highbush blueberry Vaccinium corymbosum · 25 states
- Highbush cranberry Viburnum opulus var. americanum · 22 states
- Hobblebush Viburnum lantanoides · 17 states
- Honey locust Gleditsia triacanthos · 13 states
- Indigo bush Amorpha fruticosa · 37 states
- Jack-in-the-pulpit Arisaema triphyllum · 35 states
- Jacob's ladder Polemonium reptans · 31 states
- Lanceleaf coreopsis Coreopsis lanceolata · 35 states
- Large-flowered bellwort Uvularia grandiflora · 27 states
- Largeflower tickseed Coreopsis grandiflora · 25 states
- Low prickly pear Opuntia humifusa · 31 states
- Lowbush blueberry Vaccinium angustifolium · 22 states
- Lyreleaf sage Salvia lyrata · 22 states
- Mapleleaf viburnum Viburnum acerifolium · 27 states
- Marsh marigold Caltha palustris · 28 states
- Mayapple Podophyllum peltatum · 35 states
- Mountain maple Acer spicatum · 18 states
- Nannyberry Viburnum lentago · 25 states
- Narrowleaf blue-eyed grass Sisyrinchium angustifolium · 21 states
- New Jersey tea Ceanothus americanus · 35 states
- Northern blue flag Iris versicolor · 10 states
- Northern red oak Quercus rubra · 33 states
- Northern spicebush Lindera benzoin · 31 states
- Ohio buckeye Aesculus glabra · 20 states
- Pagoda dogwood Cornus alternifolia · 30 states
- Partridgeberry Mitchella repens · 31 states
- Pawpaw Asimina triloba · 29 states
- Peachleaf willow Salix amygdaloides · 4 states
- Pin cherry Prunus pensylvanica · 20 states
- Pin oak Quercus palustris · 27 states
- Pitch pine Pinus rigida · 12 states
- Porcupine grass Hesperostipa spartea · 2 states
- Post oak Quercus stellata · 28 states
- Prairie Junegrass Koeleria macrantha · 29 states
- Purple clematis Clematis occidentalis var. occidentalis · 15 states
- Purple meadow-rue Thalictrum dasycarpum · 17 states
- Purple milkweed Asclepias purpurascens · 20 states
- Quaking aspen Populus tremuloides · 39 states
- Red baneberry Actaea rubra · 29 states
- Red chokeberry Aronia arbutifolia · 22 states
- Red pine Pinus resinosa · 13 states
- Red-osier dogwood Cornus sericea · 36 states
- Riverbank grape Vitis riparia · 20 states
- Royal fern Osmunda regalis var. spectabilis · 30 states
- Sand cherry Prunus pumila · 5 states
- Sassafras Sassafras albidum · 22 states
- Scarlet beebalm Monarda didyma · 25 states
- Scarlet oak Quercus coccinea · 28 states
- Shagbark hickory Carya ovata · 34 states
- Shingle oak Quercus imbricaria · 18 states
- Shumard oak Quercus shumardii · 22 states
- Smooth Solomon's seal Polygonatum biflorum · 34 states
- Smooth hydrangea Hydrangea arborescens · 23 states
- Smooth sumac Rhus glabra · 42 states
- Sourwood Oxydendrum arboreum · 17 states
- Southern arrowwood Viburnum dentatum · 28 states
- Southern red oak Quercus falcata · 23 states
- Spotted beebalm Monarda punctata · 29 states
- Starry false Solomon's seal Maianthemum stellatum · 19 states
- Striped maple Acer pensylvanicum · 18 states
- Sugar maple Acer saccharum · 34 states
- Sundial lupine Lupinus perennis · 28 states
- Swamp azalea Rhododendron viscosum · 15 states
- Swamp rose Rosa palustris · 27 states
- Swamp white oak Quercus bicolor · 23 states
- Sweet birch Betula lenta · 21 states
- Sweet crabapple Malus coronaria · 20 states
- Sweet-fern Comptonia peregrina · 21 states
- Sweetbay magnolia Magnolia virginiana · 17 states
- Sweetgum Liquidambar styraciflua · 26 states
- Three-flower melic grass Melica nitens · 17 states
- Trailing arbutus Epigaea repens · 24 states
- Tulip tree Liriodendron tulipifera · 27 states
- Twinleaf Jeffersonia diphylla · 15 states
- Twoleaf miterwort Mitella diphylla · 25 states
- Umbrella tree magnolia Magnolia tripetala · 17 states
- Virginia bluebells Mertensia virginica · 23 states
- Virginia creeper Parthenocissus quinquefolia · 40 states
- Virginia iris Iris virginica · 26 states
- Virginia spiderwort Tradescantia virginiana · 24 states
- Virginia springbeauty Claytonia virginica · 28 states
- Virginia strawberry Fragaria virginiana · 30 states
- Virginia sweetspire Itea virginica · 19 states
- White ash Fraxinus americana · 35 states
- White baneberry Actaea pachypoda · 33 states
- White fringetree Chionanthus virginicus · 21 states
- White oak Quercus alba · 33 states
- Whorled milkweed Asclepias verticillata · 30 states
- Wild blue phlox Phlox divaricata · 36 states
- Wild geranium Geranium maculatum · 33 states
- Wild hyacinth (Atlantic camas) Camassia scilloides · 20 states
- Willow oak Quercus phellos · 23 states
- Yellow birch Betula alleghaniensis · 21 states
- Yellow buckeye Aesculus flava · 14 states
May in a Pennsylvania native garden
May is Pennsylvania's peak bloom month: 192 of the state's 308 native plants in this directory flower in May, more than in any other month.
49 start blooming in May, including American bittersweet, American cranberry and American strawberry bush. 60 finish in May, including American beech, American hornbeam and Appalachian gooseberry, so this is the last chance to see them in flower.
117 of them grow in full or partial sun and 143 tolerate shade, so there are options for open beds and woodland edges alike. Sizes run from low plants like American alumroot and Birdfoot violet to trees such as Allegheny chinquapin and Allegheny serviceberry. For wildlife, 139 support pollinators, 116 provide food or cover for birds and 71 are caterpillar host plants.
145 of the 192 have a seed or plant listing we verified as the wild species. Be careful buying American alumroot, Common yarrow, Creeping phlox: common listings for these are often a bred variety or a different species.
Good places to start
Verified wild-species listings that take sun and are widely native, so they are forgiving first plants.
- Chokecherry Prunus virginiana · Sun, Part Shade, Shade · blooms Apr-Jul
- Green ash Fraxinus pennsylvanica · Sun, Part Shade, Shade · blooms Apr-Jun
- Smooth sumac Rhus glabra · Sun, Part Shade, Shade · blooms May-Aug