Quick answer: 102 native Texas plants have a recorded bloom range that includes May.
102 species
- American beautyberry Callicarpa americana · 10 states
- American beech Fagus grandifolia · 24 states
- American holly Ilex opaca · 24 states
- American hornbeam Carpinus caroliniana · 29 states
- American smoketree Cotinus obovatus · 2 states
- American strawberry bush Euonymus americanus · 7 states
- American wisteria Wisteria frutescens · 14 states
- Antelope-horns milkweed Asclepias asperula · 2 states
- Autumn sage Salvia greggii · 2 states
- Black tupelo Nyssa sylvatica · 19 states
- Black walnut Juglans nigra · 33 states
- Blackjack oak Quercus marilandica · 3 states
- Buffalograss Bouteloua dactyloides · 9 states
- Bur oak Quercus macrocarpa · 24 states
- Butterflyweed Asclepias tuberosa · 37 states
- Cardinal flower Lobelia cardinalis · 37 states
- Carolina jessamine Gelsemium sempervirens · 9 states
- Chinkapin oak Quercus muehlenbergii · 14 states
- Claret cup cactus Echinocereus triglochidiatus · 1 states
- Common sotol Dasylirion wheeleri · 3 states
- Common winterberry Ilex verticillata · 10 states
- Common yarrow Achillea millefolium · 31 states
- Coral bean Erythrina herbacea · 6 states
- Coral honeysuckle Lonicera sempervirens · 16 states
- Coralberry Symphoricarpos orbiculatus · 20 states
- Creosote bush Larrea tridentata · 5 states
- Crossvine Bignonia capreolata · 5 states
- Desert marigold Baileya multiradiata · 4 states
- Desert willow Chilopsis linearis · 4 states
- Drummond phlox Phlox drummondii · 1 states
- Dwarf palmetto Sabal minor · 3 states
- Eastern purple coneflower Echinacea purpurea · 22 states
- Eastern red cedar Juniperus virginiana · 36 states
- Eastern red columbine Aquilegia canadensis · 36 states
- Eastern redbud Cercis canadensis · 30 states
- Engelmann's prickly pear (cactus apple) Opuntia engelmannii · 1 states
- Farkleberry Vaccinium arboreum · 5 states
- Flowering dogwood Cornus florida · 22 states
- Fragrant sumac Rhus aromatica · 14 states
- Golden alexanders Zizia aurea · 12 states
- Green ash Fraxinus pennsylvanica · 23 states
- Green milkweed Asclepias viridis · 1 states
- Honey mesquite Prosopis glandulosa · 3 states
- Indian blanket Gaillardia pulchella · 18 states
- Indigo bush Amorpha fruticosa · 16 states
- Lanceleaf coreopsis Coreopsis lanceolata · 28 states
- Lemon beebalm Monarda citriodora · 15 states
- Loblolly bay Gordonia lasianthus · 5 states
- Longleaf pine Pinus palustris · 6 states
- Mapleleaf viburnum Viburnum acerifolium · 5 states
- Mayapple Podophyllum peltatum · 18 states
- Maypop passionflower Passiflora incarnata · 13 states
- Mealy blue sage Salvia farinacea · 1 states
- Mexican buckeye Ungnadia speciosa · 2 states
- Mexican hat Ratibida columnifera · 17 states
- Mexican olive Cordia boissieri · 1 states
- Narrow-leaf coneflower Echinacea angustifolia · 9 states
- New Jersey tea Ceanothus americanus · 31 states
- Northern catalpa Catalpa speciosa · 9 states
- Northern spicebush Lindera benzoin · 16 states
- Ocotillo Fouquieria splendens · 3 states
- Ohio buckeye Aesculus glabra · 12 states
- Pale purple coneflower Echinacea pallida · 9 states
- Peachleaf willow Salix amygdaloides · 3 states
- Pink evening primrose Oenothera speciosa · 8 states
- Plains coreopsis Coreopsis tinctoria · 16 states
- Possumhaw Ilex decidua · 7 states
- Post oak Quercus stellata · 9 states
- Quaking aspen Populus tremuloides · 24 states
- Rattlesnake master Eryngium yuccifolium · 6 states
- Red buckeye Aesculus pavia · 9 states
- Red yucca Hesperaloe parviflora · 2 states
- Richardson's alumroot Heuchera richardsonii · 8 states
- Rocky Mountain bee plant Peritoma serrulata · 22 states
- Rusty blackhaw viburnum Viburnum rufidulum · 12 states
- Sassafras Sassafras albidum · 22 states
- Scarlet sage Salvia coccinea · 3 states
- Shumard oak Quercus shumardii · 5 states
- Smooth sumac Rhus glabra · 34 states
- Southern live oak Quercus virginiana · 13 states
- Southern magnolia Magnolia grandiflora · 10 states
- Southern red oak Quercus falcata · 6 states
- Spotted beebalm Monarda punctata · 14 states
- Standing cypress Ipomopsis rubra · 6 states
- Sweetbay magnolia Magnolia virginiana · 12 states
- Sweetgum Liquidambar styraciflua · 22 states
- Texas bluebonnet (state flower) Lupinus texensis · 2 states
- Texas sacahuista Nolina texana · 1 states
- Titi cyrilla Cyrilla racemiflora · 5 states
- Twistleaf yucca Yucca rupicola · 1 states
- Virginia creeper Parthenocissus quinquefolia · 27 states
- Virginia iris Iris virginica · 9 states
- Virginia sweetspire Itea virginica · 6 states
- White ash Fraxinus americana · 31 states
- White fringetree Chionanthus virginicus · 14 states
- White oak Quercus alba · 33 states
- Wild blue Phlox divaricata · 32 states
- Willow oak Quercus phellos · 16 states
- Winecup Callirhoe involucrata · 7 states
- Yaupon holly Ilex vomitoria · 7 states
- Yellow bells (esperanza) Tecoma stans · 3 states
- Yellow necklacepod Sophora tomentosa · 1 states