National Butterfly Center 
IMPORTANT POLLINATOR PLANTS
& The Bees That Pollinate Them

National Butterfly Center 
IMPORTANT POLLINATOR PLANTS
& 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 *

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.

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)

Aloysia gratissima 

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.

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)

Arctostaphylos glauca

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.

Common Name:  Manzanita

Plant Family:  Ericaceae

Associated Bee Species:

Black-footed oil-digger bee
    (Centris atripes)

California digger bee

    (Anthophora californica)

Argemone aenea

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.

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)

Argemone sanguinea

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.  

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)

WJPEG-Plants-Bidens-Alba-NBC-#295-Spanis

Bidens alba

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.

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)

Erect spiderling  (Boerhavia erecta)

Boerhavia erecta

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.

Common Name:  Erect spiderling

Plant Family:  Nyctaginaceae

Associated Bee Species:

Green metallic bee (Augochloropsis metallica)

Crucita (Chromolaena odorata)

Chromolaena odorata

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.  

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)

Berlandier's fiddlewood (Citharexylum berlandieri)

Citharexylum berlandieri

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.

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)

Woolly croton Croton capitatus)

Croton humilis

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

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)

Pigeonberry (Duranta erecta)

Duranta erecta

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.

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)

WJPEG-Flora-Texas-ebony-NBC-#272-Ebenops

Ebenopsis ebano

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.

Common Name:  Ebony tree
Plant Family:  Fabaceae

Associated Bee Species:

Chichimeca leafcutter (Megachile chichimeca)

Honey-footed Exomalopsis (Exomalopsis mellipes)

Blanketflower (Gaillardia pulchella)

Gaillardia pulchella

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

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)

Firebush (Hamelia patens)

Hamelia patens

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.

Common Name:  Firebush
Plant Family:  Rubiaceae

Associated Bee Species:

Strand's carpenter bee (Xylocopa strandi)

WJPEG-Flora-Tenaza-NBC-#293-Havardia-pal

Havardia pallens

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

Common Name:  Tenaza tree
Plant Family:  Fabaceae

Associated Bee Species:

Common little leafcutter bee
     (Megachile brevis)

Helianthus annuus

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. 

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)

Texas sage (Leucophyllus frutescens)

Leucophyllus frutescens

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.

Common Name:  Texas Sage

Plant family:  Scrophulariaceae

Associated Bee Species:

Honey-footed Exomalopsis
      (Exomalopsis mellipes)

Malpighia emarginata

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.

Common Name:  Barbados Sherry

Plant family:  Malpighiaceae

Associated Bee Species:

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

Malvastrum americanum
    var. Americanum 
*

Notes: 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.

 

Large patches of this ative mallow grow in the back garden of the NBC and along the outer edges of the main garden.  Spiked malvastrum begins blooming in early November during its fall bloom cycle.  The plant opens its flowers in late afternoon; thus pollinators arrive to feed on it at that time as well.

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)

Malvaviscus drummondii

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

Common Name:  Turk's cap
Plant Family:  Malvaceae

Associated Bee Species:

Mexican carpenter bee  (Xylocopa mexicanorum)

Strand's carpenter bee  (Xylocopa strandi)

WJPEG-Plant-Teabush-SQUARE--NBC-#156-Mel

Melochia tomentosa

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

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)

Alamo vine (Merremia dissecta)

Merremia dissecta *

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. 

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)

Opuntia engelmannii

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.

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)

Parkinsonia aculeata

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.

Common Name:  Retama, Palo verde
Plant family:  Fabaceae

Associated Bee Species:

Tepanec long-horned bee 
    
(Melissodes tepaneca)

Phyla nodiflora

Phyla nodiflora

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.

Common Name:  Texas frog fruit
Plant family:  Verbenaceae

Associated Bee Species:

Triepeolus rufoclypeus cuckoo bee
    (Triepeolus rufoclypeus)

Quincula lobata

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

Common Name:  Purple groundcherry
Plant Family:  Solanaceae

Associated Bee Species:

Swenk's cellophane bee (Colletes swenki)

Mexican hat flwer (Rabatida columnifera)

Rabatida columnifera

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

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

Texas snout bean (Rhynchosia senna var. texana)

Rhynchosia senna var. texana *

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.

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)*

WJPEG-Shrubby-blue-salvia-NBC-#226-Salvi

Salvia ballotiflora

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.

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)

Solanum elaeagnifolium *

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

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)

WJPEG-seaside-goldenrod-NBC-#273-Solidag

Solidago sempervirens

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

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)

WJPEG-Plant-Fleabane-Purple-NBC-#109-293

Symphyotrichum sp. *

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.

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
     melliventris)

Ligated furrow bee
 (Halictus ligatus)

Esperanza (Tecoma stans)

Tecoma stans *

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.

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)
Met
alilc green bee (Augochloropsis metallica) 

Parkinson's carpenter  bee (Xylocopa
    tabaniformis parikinsoniae)

Strand's carpenter bee (Xylocopa strandi)

Cowpen daisy (Verbesina enceloides)

Verbesina enceloides

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.

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)

Skeleton-leaf goldeneye (Viguiera stenoloba)

Viguiera stenoloba *

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.

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)

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Last updated November 2019

 1-15-19