Quick answer: 116 native Iowa plants have a recorded bloom range that includes May.
116 species
- American basswood Tilia americana · 37 states
- American bittersweet Celastrus scandens · 33 states
- American bladdernut Staphylea trifolia · 28 states
- American hazelnut Corylus americana · 34 states
- American hornbeam Carpinus caroliniana · 33 states
- American plum Prunus americana · 37 states
- Bearberry Arctostaphylos uva-ursi · 34 states
- Birdfoot violet Viola pedata · 34 states
- Black cherry Prunus serotina · 35 states
- Black walnut Juglans nigra · 33 states
- Blackhaw Viburnum prunifolium · 12 states
- Blue wild indigo Baptisia australis · 23 states
- Broadleaf cattail Typha latifolia · 39 states
- Buffalograss Bouteloua dactyloides · 19 states
- Bunchberry Cornus canadensis · 18 states
- Bur oak Quercus macrocarpa · 33 states
- Butterflyweed Asclepias tuberosa · 40 states
- Canada anemone Anemone canadensis · 29 states
- Canada wild rye Elymus canadensis · 37 states
- Canadian wild ginger Asarum canadense · 30 states
- Candle anemone (thimbleweed) Anemone cylindrica · 12 states
- Cardinal flower Lobelia cardinalis · 41 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 ninebark Physocarpus opulifolius · 30 states
- Common persimmon Diospyros virginiana · 26 states
- Common winterberry Ilex verticillata · 32 states
- Common yarrow Achillea millefolium · 47 states
- Coralberry Symphoricarpos orbiculatus · 30 states
- Creeping juniper Juniperus horizontalis · 12 states
- Downy hawthorn Crataegus mollis · 24 states
- Downy serviceberry Amelanchier arborea · 37 states
- Dutchman's breeches Dicentra cucullaria · 32 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 white pine Pinus strobus · 28 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
- Heart-leaved meadow parsnip Zizia aptera · 30 states
- Highbush cranberry Viburnum opulus var. americanum · 22 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 penstemon (shell-leaf beardtongue) Penstemon grandiflorus · 12 states
- Large-flowered bellwort Uvularia grandiflora · 27 states
- Largeflower tickseed Coreopsis grandiflora · 25 states
- Longbract wild indigo (cream false indigo) Baptisia bracteata var. leucophaea · 19 states
- Low prickly pear Opuntia humifusa · 31 states
- Lowbush blueberry Vaccinium angustifolium · 22 states
- Marsh marigold Caltha palustris · 28 states
- Mayapple Podophyllum peltatum · 35 states
- Mexican hat Ratibida columnifera · 17 states
- Nannyberry Viburnum lentago · 25 states
- Narrow-leaf coneflower Echinacea angustifolia · 11 states
- New Jersey tea Ceanothus americanus · 35 states
- Northern red oak Quercus rubra · 33 states
- Northern spicebush Lindera benzoin · 31 states
- Ohio buckeye Aesculus glabra · 20 states
- Old man's whiskers Geum triflorum · 9 states
- Pagoda dogwood Cornus alternifolia · 30 states
- Pale purple coneflower Echinacea pallida · 17 states
- Partridgeberry Mitchella repens · 31 states
- Pawpaw Asimina triloba · 29 states
- Pin oak Quercus palustris · 27 states
- Post oak Quercus stellata · 28 states
- Prairie Junegrass Koeleria macrantha · 29 states
- Prairie blue-eyed grass Sisyrinchium campestre · 11 states
- Prairie crabapple Malus ioensis · 15 states
- Purple meadow-rue Thalictrum dasycarpum · 17 states
- Quaking aspen Populus tremuloides · 39 states
- Rattlesnake master Eryngium yuccifolium · 20 states
- Red baneberry Actaea rubra · 29 states
- Red pine Pinus resinosa · 13 states
- Red-osier dogwood Cornus sericea · 36 states
- Richardson's alumroot Heuchera richardsonii · 11 states
- Rocky Mountain bee plant Peritoma serrulata · 26 states
- Scarlet beebalm Monarda didyma · 25 states
- Shagbark hickory Carya ovata · 34 states
- Silver buffaloberry Shepherdia argentea · 17 states
- Smooth Solomon's seal Polygonatum biflorum · 34 states
- Smooth sumac Rhus glabra · 42 states
- Southern arrowwood Viburnum dentatum · 28 states
- Spotted beebalm Monarda punctata · 29 states
- Sugar maple Acer saccharum · 34 states
- Sundial lupine Lupinus perennis · 28 states
- Swamp white oak Quercus bicolor · 23 states
- Tulip tree Liriodendron tulipifera · 27 states
- Virginia bluebells Mertensia virginica · 23 states
- Virginia creeper Parthenocissus quinquefolia · 40 states
- Virginia iris Iris virginica · 26 states
- Virginia strawberry Fragaria virginiana · 30 states
- White ash Fraxinus americana · 35 states
- White baneberry Actaea pachypoda · 33 states
- White oak Quercus alba · 33 states
- White wild indigo Baptisia alba · 23 states
- Whorled milkweed Asclepias verticillata · 30 states
- Wild blue phlox Phlox divaricata · 36 states
- Wild geranium Geranium maculatum · 33 states
- Winecup Callirhoe involucrata · 16 states
May in an Iowa native garden
May is Iowa's peak bloom month: 116 of the state's 196 native plants in this directory flower in May, more than in any other month.
33 start blooming in May, including American bittersweet, Bunchberry and Butterflyweed. 31 finish in May, including American hornbeam, Black walnut and Bur oak, so this is the last chance to see them in flower.
88 of them grow in full or partial sun and 75 tolerate shade, so there are options for open beds and woodland edges alike. Sizes run from low plants like Birdfoot violet and Buffalograss to trees such as American basswood and American bittersweet. For wildlife, 92 support pollinators, 72 provide food or cover for birds and 46 are caterpillar host plants.
106 of the 116 have a seed or plant listing we verified as the wild species. Be careful buying Common yarrow, Eastern hop-hornbeam, Prairie crabapple: 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