Gardening

I'll never forget that rare cold morning at the National Butterfly Center in Mission, Texas. There they were Monarchs and Queens, cousin butterflies roosting in the Retama trees waiting for the sun to warm them for flight. I had already fallen in love with the trees for their flashy display of thousands of yellow blooms but also the green bark that seemed ever so prevalent.

Retama means broom in Spanish and the green bark gives it another common name Mexican paloverde or green tree. I love both names, but officially it is Jerusalem thorn. It has nothing to do with Israel, and the thorns in the tree are not a reference to Christ or the crucifixion. According to the Lady Bird Johnson Wildlife Center, the name comes from a corruption of the Portuguese and Spanish word girasol which means turning to the sun.

So like the Lady Bird Johnson Wildflower Center I'll use the name paloverde. The paloverde is known botanically as Parkinsonia aculeata and is native from Central Texas, west to Arizona and south through Mexico, actually reaching South America. The USDA map shows distribution and establishment throughout the South including Georgia and South Carolina.

Southern landscapes are rich in history with allees such as those picturesque old plantations lined with a garden walk or avenue of stately live oaks. At the Coastal Georgia Botanical Garden we have a Crape Myrtle allee, and at the National Butterfly Center, we had a paloverde allee. All are rewarding in both their performance and classic design.

Right now at the Coastal Georgia Botanical Gardens our paloverde trees are completely covered in blossoms and putting on quite a show. The flowers have five yellow petals, and one has a honey gland, it turns an orange-red giving the blooms a distinctive bicolored look. It is doubtful we will ever find butterflies roosting in the fall as they do at the National Butterfly Center, but I can tell you ours are swarming with pollinators of all types.

The paloverde is about as tough of a tree as you can grow. Should drought be so severe, it defoliates the tree the stems and bark take up the task of photosynthesis hence the reason for the green bark and stems. This defoliation even happens when cold causes the leaves to drop. The paloverde is cold hardy in zones 8 and warmer. As a point of reference, they are growing in the Dallas-Fort Worth area and part of the Texas A & M EarthKind program.

Our oldest specimen is planted in the Xeriscape Garden and is probably the only place in the world you can see the bright yellow flowers of a paloverde against a backdrop of red foliage from a Bloodgood Japanese maple. We have also been planting some in the new Sun Garden.

They will reach around 15 feet in height, possibly 25 feet. They are ever so graceful in their pendulous habit but do remember they are armed with spines. Select a sight that is well drained and receives almost full sun. They do not require or want a rich, moist soil and are capable of surviving on 12 inches of rain a year. Luxuriant moist soil can lead to rampant re-seeding. It has not been a problem in Savannah. This is a fine tree for those in zones 8-11 and looking for both drought and salt tolerance.

— Norman Winter is director of the Coastal Georgia Botanical Gardens at the Historic Bamboo Farm, University of Georgia Cooperative Extension, and author of "Tough-as-Nails Flowers for the South" and "Captivating Combinations: Color and Style in the Garden." Follow him at @CGBGgardenguru.