Lovely Lupines

Walking over the often rocky and hilly terrain of central Texas, it sometimes seems I’m in an entirely different world when compared to the Sandhill areas of South Carolina where I was born. Between the mixture of the karst limestone geology that dominates the high hills and low valley areas and the black gumbo, or Vertisol, type soils that occur here, there is little visual semblence to the gently sloping hills of white sand I knew most of my life. Still, there are a few species that overlap the ecoregions and connect the hill country to the Sandhills.

In a previous installment, we talked about the Turk’s Cap, or Bleeding Heart, (Malvaviscus aboreus var. drummondii) plant that my grandmother had planted in her yard. Besides that beautiful plant, quite a few species of birds occur both here and in South Carolina. I see species such as Northern Cardinal (Cardinalis cardinalis), Blue Jay (Cyanocitta cristata), Common Ground-Dove (Columbina passerine) and Northern Mockingbird (Mimus polyglottus) regularly here, as well as in South Carolina. Other common themes found in both places are punishing soils and temperatures that can put plants to the test. Though extremely different in particulate matter and nutrient levels, both well-drained sands and thick clay gumbo soils place stresses on plants that occasionally cause similar plants to have evolved to meet the challenges presented in differing soils. In this installment, we’ll look at very similar species that evolved just a little differently; but the family resemblance is uncanny.

The blooming of spring flowers is a favorite period of time for most people, whether they consider themselves naturalists or not. During my many years of working with Red-cockaded Woodpeckers in the Sandhills and Coastal Plains of the southeast, one of my absolute favorite flowers was the Sandhill Lupine (Lupinus diffusus). Also called, Sky-Blue Lupine, Oak Ridge Lupine and Spreading Lupine, the sight of the delicate light blue flowers in the Longleaf forests in the early spring always makes me smile.

Sandhill Lupine (Lupinus diffusus) growing in the Sandhills Region of South Carolina.

Clearly a lupine, the genus name is very appropriate. Because some lupines have the ability to choke out other plants competing for resources and because it was believed lupines depleted soils of nutrient value, they were named after the apex predator, Lupus (Wolf). The species name refers to the plants ability to spread, or diffuse, across the ground. The sky blue pea flowers grow around multiple racemes that may reach a foot in height, then open and mature to have a white spot on the standard, or upper petal. Thickly surrounding the racemes are very pubescent simple, green leaves covered in silvery hairs, giving them a nearly blue-green or greenish-gray appearance. These elliptical simple leaves are between 3”-5” in length.

The racemes (flower stalks) on this lupine were about 10" in height. The white spot on the standard is obvious in each individual pea flower.

As all lupines are in the pea family, or Fabaceae family, the flowers eventually mature into seeds encased in pods after fertilization. Upon fruiting, the entire plant will dry into a black and gray color and die. The first year of each plant’s life will be spent in a stage in which only leaves will grow, not flowering until the next year; making it a biennial.

Growing quite a taproot to extract maximum nutrients from the quickly draining and poor soils of the sandhills, this plant is notoriously hard to transplant. My friend, John Cely, and I have had several conversations about the difficulties of attempting to transplant Sandhill Lupine into identical soil conditions from where it was taken. Knowing how finicky they could be, I once used a wheelbarrow to hold a Sandhill Lupine plant and an enormous amount of the sand around it and placed it into the sandy soil at my previous home. It did not take. The only way I finally got a few plants to begin growing was to scatter a fairly large number of seed upon the poor, sandy soil at my former residence. Of 50 seeds I scattered, 5 germinated before I left South Carolina. A whopping 10% germination rate! (John, if you’re reading this, I did start figuring out how to get Farewell-To-Summer (Polygonella americana) to germinate and did have about a dozen or so take before I moved to Texas)

Now that I’m in Texas, I don’t have to go far at all to be reminded of my lovely Sandhill Lupine. In fact, the state flower is a very close relative. The Texas Bluebonnet (Lupinus texensis) is ubiquitous and, this time of year is found in front yards, fields, pastures and vacant lots everywhere. With flowers growing on nearly identical racemes as the Sandhill Lupine, the similarity is obvious. Far more common than Sandhill Lupine, the Texas Bluebonnet can grow into very dense stands, turning areas into a lovely blend of blues and greens.

The deeper blues and palmately compound leaves of the Texas Bluebonnet (Lupinus texensis).

The spots on the standards of these Texas Bluebonnets have begun turning lavender.

Unlike the light blue of the Sandhill Lupine, the Bluebonnets are a deep blue color with the white spot in the standard turning into lavender as the flower matures. The leaves of the Bluebonnet are also quite different, growing palmately compound and not simple. Still pubescent like it’s cousin, the leaves of the Bluebonnet are usually in leaflets of five; though four are not uncommon. Also like its cousin, the Bluebonnet grows in a difficult soil. The black gumbo soils around here are much more nutrient rich than the sands of South Carolina, but the levels of montmorillonite clay and limestone rock in the soil makes the ground hard and difficult to penetrate. Just ask anyone who has ever tried to dig or till this ground and he or she will tell you it could make Billy Graham cuss on national television. When it’s dry, it’s cracked and hard as a brick. When it’s wet, it sticks and cakes to every surface and is still hard as a brick.

Limestone rocks and black gumbo soil.

Roots must make a way in this difficult terrain.

Texas Bluebonnets are great for pollinator species in the early spring in Texas. They began blooming here in mid-February and should continue through early April, allowing butterflies and bees to visit when other flowers have yet to bloom.

Gray Hairstreak (Strymon melinus) on Texas Bluebonnet.

So, though my roots have been transplanted 1200 miles from the Sandhills, I don’t have to go far to see beauty in nature that reminds me of some of my favorite plants from South Carolina. Next time, we’ll look at two plants from South Carolina and Texas that have similar names, but have little in common past that.