National Butterfly Center 
& The Bees That Pollinate Them

Below is a shortlist of pollinator plants that are essential to maintaining a diversity of bee species at the National Butterfly Center.  Most of these are native to the Lower Rio Grande Valley.  Notably, some of the NBC plants most important to wild bees are fairly humble "weeds" allowed to sprout undisturbed --  scrub mallows like Rio Grande abutilon and spiked Malvastrum; unobtrusive groundcovers like frog fruit and erect spiderling; and self-seeding wildflowers like silverleaf nightshade, common sunflower, Texas snout bean and alamo vine. 


Native bees divide into two groups: "generalists" that forage on a broad array of plants, and "specialists" that feed on a particular plant genus or family.  A diverse wild bee population requires a mix of plants that sustain both generalist and specialist bees. At the NBC, mallows and aster-family flowers serve as important food sources for specialist bees.  Essential generalist bee plants include many flowering shrubs that are well-established in NBC gardens for the benefit of butterflies.  Chief among these are crucita, low croton, Turk's cap, firebush, and Berlandier's fiddlewood. 


Aster-family plants with long bloom periods -- daisies, blanket flowers, goldeneye, Mexican hat and hierba del marrano -- are also key food sources for generalist at bees at the NBC.  Ornamental trees with long bloom periods such as esperanza and Duranta erecta, both native to the neighboring Mexican state of Tamaulipas, serve the pivotal function of maintaining generalist bee populations during periods of flower scarcity caused by drought or unseasonable cold snaps. 


* Plants essential to the survival of rare & unusual native bee species have been marked with an asterisk.

Pollinator Plants Important to Native Bees

Rio Grande abutilon (Abutilon hypoleucum)

Abutilon hypoleucum *

Common Name:  Rio Grande Abutilon
Plant Family:  Malvaceae

Associated Bee Species

Aztec cuckoo leafcutter bee (Coelioxys azteca) 

Honey-footed Exomalopsis
      (Exomalopsis mellipes)
Honey-tailed Agapostemon 
     (Agapostemon melliventris)

Snow's Exomalopsis (Exomalopsis snowi)

Notes:  This native plant first blooms in April and is still blooming in November.  It grows in untended areas along the borders of the front and back gardens at the NBC.

Rio Grande Abutilon is the only NBC plant on which the little-seen Aztec cuckoo leafcutter bee has been found.  This plant also attracts significant numbers of Exomalopsis bees, Diadasia chimney bees and iridescent green sweat bees.

Aloysia gratissima 

Common Name:  Whitebrush
Plant Family:  Verbenaceae

Associated Bee Species

Florilegus condignus long-horned bee

Ringed Exomalopsis (Exomalopsis anillis)
Slosson's Cuckoo Leafcutter
(Coelioxys slossoni arenicola)
Snow's Exomalopsis (Exomalopsis snowi)
Zaptlana Leafcutter (Megachile Zaptlana)

Notes:  This native plant begins blooming in June.  It is a primary attractor of a variety of native bee genera, including leafcutters, cuckoo leafcutters, Exomalopsis bees and Florilegus long-horned bees.

Arctostaphylos glauca

Common Name:  Manzanita

Plant Family:  Ericaceae

Associated Bee Species:

Black-footed oil-digger bee
    (Centris atripes)

California digger bee

    (Anthophora californica)

Notes:  This plant is a great attractor of Centris and Digger bees during its bloom period in April. Rarely seen through most of the year, black-footed oil-digger bees mob big berry manzanita in such large numbers in mid-April that the manzanita seems to buzz with life when you walk by it.

Argemone aenea

Common Name:  Golden prickly poppy

Plant Family:  Papaveraceae

Associated Bee Species:

Augochlora aurifera golden-green sweat bee
Diadasia rinconis chimney bee
    (Diadasia rinconis)

Lasioglossum (Dialictus) sweat bee

Littoral cactus wood-borer bee (lithurgopsis littoralis)

Silver-tailed petal-cutter (Megachile montivaga)

Notes:  Golden prickly poppies provide pollen for chimney bees, sweat bees and cactus wood-borer bees in late March and early April.  Male chimney bees and wood-borer bees sleep in the poppies and seek refuge in them during bad weather.  Silver-tailed petal-cutter bees trim off pieces of the poppies' delicate petals and use them to line their nests.

Argemone sanguinea

Common Name:  Red prickly poppy

Plant Family:  Papaveraceae

Associated Bee Species:

Compact Anthophorula (Anthophorula compactula)
Diadasia rinconis chimney bee (Diadasia rinconis)

Lasioglossum (Dialictus) sweat bee

Little prickly pear long-horned bee
(Melissodes opuntiellus)

Littoral cactus wood-borer bee
   (lithurgopsis littoralis)

Notes:  Like the golden prickly poppies shown above, red prickly poppies provide pollen for chimney bees and cactus wood-borer bees in late March and early April. Male chimney bees, long-horned bees, Anthophorulas and wood-borer bees sleep in the poppies and seek refuge in them during bad weather.  


Bidens alba

Common Name:  Spanish needles, Beggarticks

Plant Family:  Asteraceae

Associated Bee Species:

Aztec cuckoo leafcutter (Coelioxys azteca)

Heriades resin bee (Heriades variolosa)

Honey-footed Exomalopsis (Exomalopsis mellipes)

Ligated furrow bee (Halictus ligatus)

Similar Exomalopsis (Exomalopsis similis)

Notes:  Bidens alba attracts a multitude of small bee species during the fall.  It is one of two plants on which the rare Aztec cuckoo leafcutter has been found at the NBC.

Erect spiderling  (Boerhavia erecta)

Boerhavia erecta

Common Name:  Erect spiderling

Plant Family:  Nyctaginaceae

Associated Bee Species:

Green metallic bee (Augochloropsis metallica)

Notes:  This dainty and easily-overlooked native plant is a favorite of sweat bees on NBC grounds.  It grows in untended areas along the borders of the front gardens.

Crucita (Chromolaena odorata)

Chromolaena odorata

Common Name:  Crucita

Plant family:  Asteraceae

Associated Bee Species:

Honey-footed Exomalopsis (Exomalopsis mellipes)
Honey-tailed Agapostemon (Agapostemon melliventris )

Ringed Exomalopsis (Exomalopsis anilis)

Shining oil-digger bee (Centris nitida)
Snow's Exomalopsis (Exomalopsis snowi)

Texan Agapostemon (Agapostemon texanus)

Notes:  Crucita blooms throughout the fall at the NBC.  In late November,  after most plants have succumbed to cold, crucita serves as the most reliable food source for many NBC generalist bee species. 


At the NBC, crucita is the sole documented pollen source for the ringed Exomalopsis and for the shining oil-digger bee.  

Berlandier's fiddlewood (Citharexylum berlandieri)

Citharexylum berlandieri

Common Name:  Berlandier's fiddlewood

Plant Family:  Verbenaceae

Associated Bee Species:

California digger bee (Anthophora californica)

Four-banded Nomia (Nomia tetrazonata)

Honey-tailed Agapostemon
      (Agapostemon melliventris)

Notes:   During the fall (Sept. - Nov.) this plant is the principal source of pollen and nectar at the NBC for honey-tailed Agapostemons.  Berlandier's fiddlewood is also an important food source for spring bees.  It is the only spring plant at NBC on which Nomia bees have been spotted.

Woolly croton Croton capitatus)

Croton humilis

Common Name:   Low croton
Plant Family:  Euphorbiaceae

Associated Bee Species:

Birkmann's cellophane bee (Colletes birkmanni)

Chichimeca leafcutter bee (Megachile chichimeca)

Snow's Exomalopsis (Exomalopsis snowi)

Zaptlana leafcutter bee (Megachile zaptlana)

Notes:  This plant is the sole documented pollen source at the NBC for the Chichimeca leafcutter and Birkmann's cellophane bee.

Pigeonberry (Duranta erecta)

Duranta erecta

Common Name:  Pigeonberry
Plant Family:  Verbenaceae

Associated Bee Species:

Black-footed oil-digger bee (Centris atripes)

California digger bee (Anthophora californica)

Capistrata digger bee (Anthophora capistrata)

Florilegus condignus Long-horned bee

Tepanec long-horned bee (Melissodes tepaneca)

Notes:  This verbena-family plant is a key or sole pollen source for a variety of generalist bees during the fall at the NBC.  Without this steadfast hardy bloomer at hand, the bee species listed here would struggle for survival at the NBC during periods of unusual autumn drought or cold.

Duranta erecta is native to Tamaulipas, the Mexican state directly south of the National Butterfly Center.


Ebenopsis ebano

Common Name:  Ebony tree
Plant Family:  Fabaceae

Associated Bee Species:

Chichimeca leafcutter (Megachile chichimeca)

Honey-footed Exomalopsis (Exomalopsis mellipes)

Notes:  Texas ebony blooms in June and July at the NBC, when its flowers are mobbed by honey bees.  This tree also attract leafcutter and Exomalopsis bees.

Blanketflower (Gaillardia pulchella)

Gaillardia pulchella

Common Name:  Blanketflower
Plant family:  Asteraceae

Associated Bee Species:

American bumble bee (Bombus pensylvanicus)

Ligated furrow bee (Halictus ligatus)

Parallel Leafcutter Bee (Megachile parallela)

Triepeolus rufoclypeus cuckoo bee
   (Triepeolus rufoclypeus)

Notes:  This is one of the preferred plants at the NBC for the endangered American bumble bee.


Guaiacum angustifolium

Common Name:  Guayacan
Plant Family:  Zygophyllaceae

Associated Bee Species:

California digger bee (Anthophora californica)
Honey bee (Apis mellifera)
Parkinsonia carpenter bee (Xylocopa
    tabaniformis parkinsoniae)

Notes This singular plant,
a hardwood evergreen native
to the Lower Rio Grande Valley,

is an important pollen source in

early spring (February-March), when
few plants are in bloom.  It attracts
bees of multiple genera.  Guayacan

is a member of the same plant
family as creosote bush.

Firebush (Hamelia patens)

Hamelia patens

Common Name:  Firebush
Plant Family:  Rubiaceae

Associated Bee Species:

Strand's carpenter bee (Xylocopa strandi)

Notes:  During the fall at the NBC, firebush is an essential food for Strand's carpenter bee, a species found within the U.S. only in southern Texas.


Havardia pallens

Common Name:  Tenaza tree
Plant Family:  Fabaceae

Associated Bee Species:

Common little leafcutter bee
     (Megachile brevis)

Notes:  When tenaza trees bloom in June and July at the NBC, they are mobbed by honey bees and by common little leafcutter bees. 

Helianthus annuus

Common Name:  Common sunflower

Plant family:  Asteraceae

Associated Bee Species:

Coelioxys edita cuckoo leafcutter bee
    (Coelioxys edita)

Ligated furrow bee (Halictus ligatus)

Sunflower chimney bee (Diadasia enavata)
Tepanec long-horned bee 
    (Melissodes tepaneca)

Texan Agapostemon (Agapostemon texanus)

Triepeolus rufoclypeus cuckoo bee
      (Triepeolus rufoclypeus)

Notes:  At the NBC, a long bed of sunflowers that borders the canal south of the main gardens sustains a multitude of wild bee species.  Many of these are species that show a preference for aster-family plants. 


The common sunflower is the only plant on which the sunflower chimney bee and the Coelioxys edita cuckoo leafcutter bee have been documented at the NBC. 

Texas sage (Leucophyllus frutescens)

Leucophyllus frutescens

Common Name:  Texas Sage

Plant family:  Scrophulariaceae

Associated Bee Species:

Honey-footed Exomalopsis
      (Exomalopsis mellipes)

NotesTexas sage is a documented pollen source for a variety of long-horned bees, mining bees and sweat bees.  In fall, 2018, this plant was visited by the generalist pollinator known as the honey-footed Exomalopsis.  This beautiful wild bee rarely appears within the U.S. outside of south Texas.

Malpighia emarginata

Common Name:  Barbados Sherry

Plant family:  Malpighiaceae

Associated Bee Species:

Black-footed oil-digger big (Centris atripes)Shining oil-digger bee (Centris nitida)

NotesCenter bees use the oils from Malpighia to line the walls of their nest chambers.  In early May, these bees can be seen buzzing happily through the Barbados cherry in large numbers.

Malvastrum americanum
    var. Americanum 

Common Name:  Spiked Malvastrum
Plant Family:  Malvaceae

Associated Bee Species:

Golden Augochlora sweat bee 
    (Augochlora aurifera)

Ochraceous chimney bee  (Diadasia ochracea)

Melissoptila otomita long-horned bee
    (Melisoptila otomita  

Tropical Diadasia chimney bee
    (Diadasia tropicalis)

Notes: At NBC, this plant is essential to the survival of the rare Messiloptila otomita long-horned bee.  In early November 2019, hundreds of female Melissoptila otomita appeared on a single stand of Malvastrum americanum.  The plant opens its flowers in late afternoon; thus pollinators arrive to feed on it at that time as well.

Malvaviscus drummondii

Common Name:  Turk's cap
Plant Family:  Malvaceae

Associated Bee Species:

Mexican carpenter bee  (Xylocopa mexicanorum)

Strand's carpenter bee  (Xylocopa strandi)

Notes:  Turk's cap is a principal food source for carpenter bees at the NBC.  


Melochia tomentosa

Common Name:  Teabush, Wooly Pyramid Bush
Plant Family:  Malvaceae

Associated Bee Species:

California digger bee (Anthophora californica)

Florilegus long-horned bee (Florilegus condignus)

Little chimney bee (Diadasia diminuta)

Little prickly pear long-horned bee 
Melissodes opuntiellus)

Mason bee (Osmia sp.)

Tepanec Long-horned bee (Melissodes tepaneca)

Tropical Diadasia chimney bee (Diadasia tropicalis)

Notes:  Teabush sustains a broad array of bee genera in April at the NBC.

Alamo vine (Merremia dissecta)

Merremia dissecta *

Common Name:  Alamo vine
Plant Family:  Convolvulaceae

Associated Bee Species:

Aztec sweat bee (Augochlora azteca)

Beautiful ceratina (Ceratina cobaltina)

Crooked-legged bee (Ancyloscelis apiformis)
Dialictus sweat bee (Lasioglossum
     Subgenus Dialictus)

Melitoma Marginella Chimney Bee 
     (Melitoma marginella)

Notes:  At the NBC, Alamo vine is the sole or principal pollen source for several bee species that are rarely seen in most of the United States.  Alamo vine blooms at the NBC throughout the fall into late November.


Alamo vine grows most densely along the canal south of the NBC's main gardens and should be left undisturbed wherever seen. 

Opuntia engelmannii

Common Name:  Texas prickly pear
Plant family:  Cactaceae

Associated Bee Species:

Aztec sweat bee (Augochlora azteca)
Compact Anthophorula
 (Anthophorula compactula)

Diadasia rinconis chimney bee
Frisky Svastra (Svastra petulca)

Little prickly pear long=horned bee

    (Melissodes opuntiellus)

Littoral cactus wood-borer bee
   (lithurgopsis littoralis)

Osmia subfaciata mason bee
Tepanec long-horned bee (Melissodes tepaneca)

Notes:  In March and early April, when Texas prickly pear blooms, it attracts a variety of generalist bees and is the sole food source for others.  At least four species appear exclusively or nearly exclusively on this cactus at at the NBC.  Osmia subfasciata mason bees uses plant materials from prickly pear cactus to build their nests.

Palafoxia texana

Common Name:  Texas palafox
Plant family:  Asteraceae

Associated Bee Species:

Hercules Sphecodes bee
(Sphecodes heraclei)

Panamanian masked bee
    (Hylaeus panamensis)

Texas palafox
    (Palafoxia texana)

Notes:  In November, small bees

like furrow bees, Hercules Sphecodes and masked bees congregate in large numbers on the blossoms of Texas palafox.

Parkinsonia aculeata

Common Name:  Retama, Palo verde
Plant family:  Fabaceae

Associated Bee Species:

Tepanec long-horned bee 
(Melissodes tepaneca)

Notes:  Retama, a kind of Palo verde, is a principal food source of the Tepanec long-horned bee during the spring.  During April at the NBC, a single retama tree can be mobbed by dozens of female Tepanec long-horned bees.

Phyla nodiflora

Phyla nodiflora

Common Name:  Texas frog fruit
Plant family:  Verbenaceae

Associated Bee Species:

Triepeolus rufoclypeus cuckoo bee
    (Triepeolus rufoclypeus)

Notes:  This little plant is easy to overlook.  It is a low groundcover that grows throughout the NBC's grounds.  During the fall, Texas frog fruit flowers are visited by an array of small sweat bees and by Triepeolus cuckoo bees.


Prosopis glandulosa

Common Name:  Honey mesquite
Plant Family:  Fabaceae

Associated Bee Species:

Swenk's cellophane bee (Colletes swenki)
Texas Agapostemon
Zaptlana leafcutter (Megachile zaptlana)

Notes: This tree is an important source of pollen for several bee species, in early spring before many plants have begun blooming (February -

Quincula lobata

Common Name:  Purple groundcherry
Plant Family:  Solanaceae

Associated Bee Species:

Swenk's cellophane bee (Colletes swenki)

Notes: This small plant blooms in April.  It is the principal plant on which Swenk's cellophane bee appears at the NBC.

Mexican hat flwer (Rabatida columnifera)

Rabatida columnifera

Common Name:  Mexican hat
Plant family:  Asteraceae

Associated Bee Species:

Florilegus condignus long-horned bee
Frisky Svastra 
(Svastra petulca)

Hercules Sphecodes cuckoo bee 
    (Sphecodes heraclei)

Ligated furrow bee (Halictus ligatus)

Melissodes Long-horned bees

Texas Agapostemon (Agapostemon texanus)

Triepeolus rufoclypeus cuckoo bee

Notes:  On NBC grounds, the green sweat bee species known as the Texas Agapostemon has been found only on this flower and on sunflowers.

Texas snout bean (Rhynchosia senna var. texana)

Rhynchosia senna var. texana *

Common Name:  Texas snout bean
Plant Family:  Fabaceae

Associated Bee Species:

Black-footed oil-digger bee (Centris atripes)

Slender resin bee (Megachile exilis)

*Toluca leafcutter bee (Megachile cf. toluca)*

Notes:  Texas snout bean is the sole documented NBC plant visited by the leafcutter species identified as Megachile cf. toluca. This bee was discovered at the NBC in fall, 2018 -- the only record of this species (and its entire subgenus) inside of the U.S.  Slender resin bees also feed solely on this plant at the NBC.


Planting more of this perennial in other areas of the NBC could add to the security of the NBC's Megachile cf. toluca and resin bee populations.


Salvia ballotiflora

Common Name:  Shrubby blue salvia
Plant family:  Laminaceae

Associated Bee Species:

California digger bee (Anthophora californica)

Capistrata digger bee (Anthophora capistrata*

Megachile exilis resin bee

Megachile (Megachiloides) leafcutter bee

Solanum exomalopsis (Exomalopsis solani)

Notes: Shrubby blue salvia is the sole plant on which the Capistrata digger bee and the unhappy long-horned bee have been sighted at the NBC.  The Capistrata digger bee is rarely seen north of the Mexican border, but at NBC it is was a frequent visitor to this plant in late April 2019.

Solanum elaeagnifolium *

Common Name:  Silverleaf nightshade

Associated Bee Species:

*American bumble bee (Bombus pensylvanicus)

California digger bee (Anthophora californica)

Green metallic bee (Augochloropsis metallica)

Mexican carpenter bee (Xylocopa mexicanorum)*

Similar Exomalopsis (Exomalopsis similis)

Notes:  During early fall, the endangered American bumble bee is a frequent visitor of silverleaf nightshade at the NBC.


Solidago sempervirens

Common Name:  Seaside goldenrod

Associated Bee Species:

Golden Augochlora (Augochlora aurifera)

Honey-footed Exomalopsis (Exomalopsis mellipes)

Honey-tailed Agapostemon (Agapostemon melliventris)
Ligated sweat bee
(Halictus ligatus)

Nevada Dieunomia (Dieunomia nevadensis

Similar Exopmalopsis (Exomalopsis similis)
Texas cuckoo leafcutter bee (Coelioxys texana)

Notes:  During early fall, seaside goldenrod attracts countless bees to the front garden at the NBC. 


Symphyotrichum sp. *

Common Name:  Hierba del marrano
Plant family:  Asteraceae

Associated Bee Species:

Dwarf epeolus cuckoo bee (Epeolus pusillus)

Green metallic bee (Augochloropsis metallica)

Honey-tailed Agapostemon (Agapostemon

Ligated furrow bee
 (Halictus ligatus)

Notes:  Hierba del marrano is the sole plant at the NBC that has been documented as a nectar source for the beautiful, violet-eyed dwarf Epeolus cuckoo bee.  Small numbers of this plant appeared at the NBC in November, 2018:  all were visited by multiple specimens of this cuckoo species.  Planting more of these flowers might buttress the population of this remarkable bee.

Esperanza (Tecoma stans)

Tecoma stans *

Common Name:  Esperanza
Plant Family:  Bignoniaceae  

Associated Bee Species:

Ancyloscelis chimney bee (Ancyloscelis apiformis)

Aztec sweat bee (Xylocopa mexicanorum)

American bumblebee (Bombus pensylvanicus)

Melitoma Marginella Chimney Bee 
    (Melitoma marginella)
alilc green bee (Augochloropsis metallica) 

Parkinson's carpenter  bee (Xylocopa
    tabaniformis parikinsoniae)

Strand's carpenter bee (Xylocopa strandi)

Notes:  Esperanza provides food for both generalist and specialist bees during periods of drought and cold when few other plants are in bloom. Esperanza is a pivotal food source at NBC for carpenter bees and chimney bees; without esperanza, some carpenter bee species might well disappear from NBC. The proximity of some NBC esperanza plants to a canal may be key to the abundance of unusual chimney bees in the area.  Chimney bees often require water to build their nests.

Cowpen daisy (Verbesina enceloides)

Verbesina enceloides

Common Name:  Cowpen daisy
Plant family:  Asteraceae

Associated Bee Species:

Frisky Svastra (Svastra petulca)

Ligated furrow bee (Halictus ligatus)

Melissoptila otomita long-horned bee
    (Melissoptila otomita)
Slosson's cuckoo leafcutter bee
    (Coelioxys slossoni  arenicola)

Zaptlana leafcutter bee (Megachile zaptlana)

Notes:  Cowpen daisy is an important pollen and nectar source both for generalist bees, and for bees that specialize in aster-family plants. Cowpen daisies are visited continuously and heavily by wild bees during the fall at the NBC.

Skeleton-leaf goldeneye (Viguiera stenoloba)

Viguiera stenoloba *

Common Name:  Skeleton-leaf goldeneye,     resinbush
Plant family:  Asteraceae

Associated Bee Species:

Hercules Sphecodes cuckoo bee
(Sphecodes heraclei)

Hostile leafcutter (Megachile inimica)

Policaris leafcutter (Megachile policaris

Sabine's Svastra (Svastra sabinensis)

Snow's Exomalopsis (Exomalopsis snowi)

Similar Exomalopsis (Exomalopsis similis)

Texas cuckoo leafcutter (Coelioxys texanus)

Wilmatte's Tetraloniella (Tetraloniella wilmattae)

Notes:  Skeleton-leaf goldeneye is the flower most frequently visited by NBC bees throughout thes pring and  fall.  This plant sustains a varied array of generalist and aster-family specialist bees.  It is the only NBC plant on which Sabine's Svastra, the similar Exomalopsis and the rare Wilmatte's Tetraloniella have been sighted.  It is s a favorite food of at least two leafcutter species.

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Last updated March 2020