11/10/2017 Esperanza

11/10/2017 – Esperanza:  The Bumblebee’s Favorite Flower

The golden yellow of a fresh esperanza blossom is streaked with dark orange “landing lines.” These lines serve as bee guides, directing the insects into the nectar-laden heart of the flower. Robert Benson photo.

The warm days of Indian summer have initiated a major blooming of my esperanza.  It is close to nine feet high and just covered with those golden trumpet shaped blossoms.  The bees and butterflies have discovered the flowers and the plant is teeming with nectaring insects.  I have identified Queens, Pipevine Swallowtails, Variegated Fritillaries, Snouts, Dusky-winged Skippers, Sulfurs, and even Little Blues crowding around the plant.

However, the bumblebees captured my attention.  I have seen so few bumblebees in the years since the drought of 2011 that I suspected they had been all but extirpated here in south Texas.  I checked Bumblebeewatch.org to see how many  sightings were recorded for Bee County in 2017.  None.  So I checked for all the years from 2011 through 2017.  Again, “No Results Found.”  I was beginning to think I was not accessing the database correctly, so I decided to look for all of Texas, not just Bee County.  Success!  There were records of bumblebees in Texas, mostly in the Houston and Dallas areas.  There was only one though in south Texas:  In the Rio Grande Valley on November 2, 2014.  The map was painfully blank for most of south and west Texas.

The lack of records was my fault.  I know I have seen a bumblebee or two around my flowers in the past year.  And, just yesterday, I identified three American Bumblebees (Bombus pensylvanicus) on my esperanza.  I have just failed to report my sightings.  Well, I will definitely correct that!

There are nine species of bumblebees found in Texas.  The American Bumblebee seems to be the most common.  Texas Parks and Wildlife has a bumblebee identification guide on its website.  The patterns of yellow fuzz on the thorax and abdomen are the distinguishing marks.  The bumblebees I have seen have yellow on the front of the thorax and two yellow bands on the abdomen.  This patterning indicates these were American Bumblebees.

Those all shiny, black “bumblebees” you see are not true bumblebees, but Southern Carpenter Bees.  Carpenter bees feed on esperanza nectar along with the bumblebees.  They therefore also assist with pollination.  However, unlike bumblebees which live in small colonies, carpenter bees are solitary bees.

This bumblebee displays the yellow patterning on the thorax and abdomen. The fuzzy yellow hairs capture pollen grains as the plump bee visits flowers. Wikimedia Commons photo.

Esperanza has the perfect kind of flower for bees, especially the larger bees.  The yellow throat of the flower is striped with dark orange “landing lines.”  These bee guides lead the foraging bee directly into the heart of the flower where rich nectar awaits the insect.   A big bee is a tight fit inside the trumpet-shaped blossom.  This ensures the bee will definitely contact the pollen-bearing stamens.  All those fuzzy hairs on the bee’s body pick up pollen.  Some of that pollen will be transferred to the next flower…and the next, facilitating pollination of the esperanza.  You’ll know your esperanza has been pollinated because it will soon produce dozens of bean-like pods.

Not every gardener likes those seedpods.  Some people consider them so unsightly, that they cut them off as soon as they form.  This encourages longer bloom time of your esperanza as well, so I guess it is a good idea.  There is also a variety of esperanza (Tecoma stans X Burchiii) that seldom sets seed, if you want to save yourself some work.

Even though esperanza is a Texas wildflower (it is native to the Trans-Pecos) most of the nursery-sold esperanzas are a cultivar called Esperanza ‘Gold Star.’  This cultivar came from a plant found in a private San Antonio garden in the 1990s.  Grower Greg Grant says that Gold Star “is intermediate between the West Texas Tecoma stans angustata and the tropical Tecoma stans stans.  The flower and leaf size is intermediate between the two.” Grant selected this cultivar because it blooms much sooner than the other forms of esperanza, sometimes when the plant is just a seedling.

Southern Carpenter Bees are the same size as bumblebees but are shiny black all over. Both carpenter bees and bumblebees are visiting our esperanza on warm fall days. Wikimedia Commons photo.

If you are purist, and only want to grow Texas natives, the West Texas subspecies is for you.  It is also more cold-hardy than the tropical esperanza but it may also freeze back.  If it does freeze, just cut the shrub back to the ground and it will come back next spring in all its golden glory.

Esperanza is not the only wildflower to attract bumblebees, but it is one of the best.  Also, it seems bumblebees are on the decline, especially in Texas.  The Texas Native Bee Co-op remarks on their website:  “There is a real need to document bumblebee species occurrence in the state in order to evaluate their persistence and overall conservation status.”  So, grow esperanza and other big-bee friendly flowers.  Report your bumblebee observations to bumblebeewatch.org to help conserve these important pollinators!