Bodacious Borers

Cottonwood Borer

As spring turns into summer in Central Texas, the heat brings out some of our most interesting creatures, most notably the native wood-boring beetles.  This group encompasses many species and families of beetles, all of whom eat wood either in their larval or adult form.  Most often they are found in or around dead or dying trees, as they are vital players in enabling the turnover of weak trees with strong ones, and acting as primary decomposers of wood which allows for the recycling of nutrients back into the soil.

One large family of beetles in the wood-boring group is the longhorn beetles, or Cerambycidae, typically characterized by their extremely long antennae which are often as long or longer than the beetle’s body.  Their family scientific name comes from the mythological Greek shepherd Cerambus, who was turned into a large beetle with horns after an argument with nymphs.  Three of the more noticeable wood-boring longhorn beetles in our area include the Banded Hickory Borer (Knulliana cincta), Cottonwood Borer (Plectrodera scalator), and Texas Bumelia Borer (Plinthocoelium suaveolens plicatum).

Banded Hickory Borer

With a body length of up to 1.4 inches, the Banded Hickory Borer is a fairly slender, typically gray to reddish-brown beetle with a pair of pale marks near the base of the elytra or wing covers that are sometimes absent, and tiny spines at the ends of the elytra.  Eggs are laid by the adults in bark crevices or directly into hardwoods such as oak, pecan, walnut, willow, and hackberry, upon which their larva feed.  In their first season, the larva feed just beneath the bark, then head deeper into the wood as they develop, a cycle which takes two to three years to complete.

Cottonwood Borer

The Cottonwood Borer is an elongate, unmistakably robust beetle with black and white markings that are formed by contrasting areas of white pubescence or fine short hairs on black body parts.  At a body length of up to 1.6 inches, the summer-active adults lay eggs in August and September on cottonwood and willow, where larva bore into the base and overwinter.  After two or three years to reach maturity, they pupate in chambers beneath the bark and emerge as adults in late spring, and are often found feeding on new shoots, leaf petioles (stems), and the bark of their host trees.

Texas Bumelia Borer

One can hardly miss the bright iridescence of the metallic green Texas Bumelia Borer, with its contrasting reddish-orange and black legs. The larva of this species feed on gum bumelia and mulberry, developing in the roots and trunks of these host plants.  With a body length of 1.5 inches, the adults are diurnal and often found on the trunks of their host plants, although they typically feed on flower nectar and are attracted to lights.

Despite their large size, most native wood-boring beetles are not pests.  Instead, they take advantage of dead and dying trees and aid in the natural decomposition process. As you venture out and about this summer, see if you can find some of these bodacious borers!

Beguiling Bloomers

Pink Stonecrop

Springtime in Central Texas brings a host of familiar wildflowers blooming in meadows and woodlands, and along grassy roadsides. But each year the seasonal conditions may vary, based largely on the timing and amount of rainfall.  While many species are widespread from year to year, some appear infrequently, others only in certain habitats, and many go almost completely unnoticed.

Clasping Venus’ Looking-glass

Clasping Venus’ Looking-glass or Clasping Bellflower (Triodanis perfoliata) is a distinctive annual that can be found growing in open often disturbed areas, sometimes appearing even in cultivated flower gardens.  In April and May, violet-blue, 5 petaled, wheel- to bell-shaped flowers, 0.5 to 0.75 inches across, are set singly in the axils of rounded green leaves that clasp the erect, slender, unbranched stems.  Inconspicuous at 6 to 18 inches high, this species is differentiated from five other Triodanis species found in Texas by its almost circular, toothed, clasping leaves.

Pink Stonecrop, also called Widow's Cross

Pink Stonecrop or Limestone Stonecrop (Sedum pulchellum), is a low-growing, apparently rare annual found on rocky ground in full sun, often among cactus and other Sedum species. Smooth, stem-clasping, cylindrical pale to lime green leaves (often with a reddish tinge), to 1 inch long, are densely arranged along the ascending to spreading stems.  These stems are topped with horizontally branched inflorescences that bloom from March to May, with numerous 4-petaled, pale pink flowers, to 0.5 inches across.  The petals are arranged in a cross-like pattern, giving rise to its other common name of Widow’s Cross. The Travis County population of this species, most often found on hilltops in the Bull Creek watershed, is disjunct by over 150 miles from other more eastern and northern populations, and likely represents the southwestern limit of its native distribution.

Heller's Plantain

Highly overlooked but quite common is Heller’s Plantain or Cedar Plantain (Plantago helleri), an erect annual that grows only in Central to West Texas and in southern New Mexico, typically in shallow, stony soils and on limestone bedrock exposures. From March through May, this species displays unusual, slightly overlapping flowers clustered at the top part of each stalk.  The flowers are quite small at 0.25-inches wide, with 4 off-white, nearly translucent petals that have a dark red center.  The stalks, to 10-inches high, arise from narrow, linear, basal leaves, to 8-inches long, and both stalks and leaves are softly hairy.  This species is can be commonly found along gravelly roadsides, and it is one of the host plants for the beautiful Common Buckeye butterfly.

Common Buckeye

Each spring, remember to look beyond the bluebonnets, paintbrushes, firewheels, and Mexican hats and take a closer look, because you just might be rewarded with one of these beguiling little bloomers!

Resilient Trees

The beginnings of Winter Storm Uri

With winter storm Uri well behind us, many observations are being made regarding which tree species successfully survived the 8-day stretch of extreme winter weather conditions.  First and foremost, all trees that are native to Central Texas generally fared much better than their non-native counterparts.  Over the centuries, native species have adapted to all sorts of weather conditions, from cycles of droughts and floods, heat and cold, and even accumulations of ice or snow.  These adaptations greatly increase each native species’ resiliency over time.

A second factor that determined the survival of a native tree species was whether it was evergreen or deciduous.  The foliage of evergreen species increases the surface area that can trap ice and heavy snow, causing limbs to bow, split, and break, which can weaken the entire structure of the tree.  While deciduous trees can be covered in ice and snow, in winter they do not have foliage that can trap the extra weight that can cause permanent damage.

Third, established plants have a much better chance of survival in extreme winter weather conditions, so now is the time to plant!   While there are many desirable native trees that are deciduous, there are several that are also attractive bloomers in the spring, including Escarpment Black Cherry (Prunus serotina var. eximia), Roughleaf Dogwood (Cornus drummondii), and Rusty Blackhaw Viburnum (Viburnum rufidulum).

Escarpment Black Cherry in bloom

Escarpment Black Cherry fruit

Found only in the limestone-based soils in Central Texas, Escarpment Black Cherry is a distinct and isolated subspecies of native Black Cherry (Prunus serotina). Growing up to 50 feet tall, it is distinguished from other subspecies in Texas by its intermediate height and its virtually hairless, pointed elliptical green leaves with finely toothed margins that turn golden yellow in fall. It has attractive silvery bark and long showy clusters of tiny white flowers in March to April followed by purplish-red fruits that are favored by wildlife.  This native cherry prefers sunny areas in wooded canyons and on slopes, and is a larval host plant for many species of butterflies and moths including Eastern Tiger Swallowtail, Two-tailed Swallowtail, Cecropia Moth, and White Furcula.

Roughleaf Dogwood in bloom

Roughleaf Dogwood fruit

Roughleaf Dogwood is a small tree to 16 feet with opposite, prominently veined, oval, green leaves with an abruptly drawn-out tip, slightly rough above and slightly velvety below, that turn purplish-red in fall.  From April to early June numerous broad clusters of cream-colored flowers appear at the ends of branches, developing into small, fleshy, bright white, spherical fruits.  This native dogwood prefers partially shady, wooded limestone hills, and provides cover for various species of wildlife, especially birds, as it spreads from root sprouts and if allowed, eventually creates a natural thicket.

Rusty Blackhaw Viburnum in bloom

A shapely small tree, typically to 18 feet but sometimes taller, Rusty Blackhaw Viburnum has attractive, glossy dark-green paired leaves that turn reddish-purple in fall, reddish-brown twigs, and dark bark that separates into rectangular plates. Platter-shaped clusters of tiny, creamy white flowers in March to April are followed by small, oval, waxy, blue-black fruits that are relished by several species of birds and mammals.  This native viburnum prefers woodland edges and thickets in partial shade, and is of special value to native pollinators like bumble bees.

Rusty Blackhaw Viburnum fruit

Rusty Blackhaw Viburnum fall color

It’s important to note that while winter storm Uri was no doubt an exceptional weather event, it’s never too early to plant some of our more resilient native trees!

Ancient Alligators

Texas Alligator Lizard

An ancient and widespread lizard family, Anguidae originated in the Triassic Period, over 100 million years ago.  Today there are 67 species recognized worldwide, with 8 found in North and Central America. Members of a large branch of the snake/lizard evolutionary tree that use their strong jaws rather than tongues to draw food into the mouth, Anguids reserve their hard, slightly forked tongues as chemosensory organs used to search for food, mates, and safe refuge.  

One subfamily within this group is called the alligator lizards, so named due to a vague resemblance to an alligator – a flat, wedge-shaped head, little neck definition, small, thin legs, and scales fairly large and shingled that barely overlap one another. These lizards shed in one piece, much like a snake, turning the old skin inside out as they crawl out of it.  They can also exhibit tail autonomy, the ability to shed their tail as a self-defense mechanism to elude a predator’s grasp and allow escape. While they have the ability to regrow their tail over a period of weeks or months, the new tail is often shorter and distinctly different in appearance from the original tail.

The only species of alligator lizard in Texas is the Texas Alligator Lizard (Gerrhonotus infernalis). Males have wider, more triangular heads than females, but both can grow up to 18 inches long, including their tail. Ground color ranges from light tan to dark brown, sometimes with a reddish cast, with 7 to 10 black and white flecked bands across the body. Newly hatched individuals look entirely different than the adults, with striking copper-colored heads and boldly banded black and cream bodies that resemble centipedes or millipedes.

Generally preferring moist areas of foothills to lowland limestone canyons, staying near springs, creeks, and streams, the Texas Alligator Lizard can even be found in suburban areas near these habitats.  They feed primarily on insects, spiders, and small vertebrates. However, they are secretive in nature, hiding under surface cover such as fallen tree limbs, forest undergrowth, and in rocky crevices.  They can be pugnacious when caught, often thrashing about and able to deliver a painful bite. When threatened by a predator, they may flee to water as they are good swimmers, or perform lateral undulation by folding in their thin limbs and slithering away quickly like a snake.   

Depending on the temperature or season, Texas Alligator Lizards may be active by day or night. In spring they are often arboreal as their tails are prehensile and assist in climbing, mating and feeding in vine tangles and other dense vegetation up to 9 feet off the ground.  Fall is mating season, with males fighting each other for the right to court a female.  Eggs are laid in clutches of 5 to 31 under rocks and in crevices between February and June, with females producing a second clutch if conditions are favorable. Unlike many other reptile species, females will remain with their clutch of eggs for the few months it takes them to incubate.

Texas Alligator Lizards are found throughout a few disjunct localities in the Big Bend region and in much of the Edwards Plateau, and are the largest limbed lizards in Texas. While their secretive nature means they often go undetected, it is a special treat to discover and observe one of these ancient alligators!

A Water Dance of Grebes

Eared Grebe in winter plumage, lacking the characteristic and showy golden ‘ear’ feathers.

Winter is one of the best times to observe waterfowl in central Texas. Several species spend the colder months on our quiet lakes, reservoirs, and ponds, searching for food in the open, unfrozen waters.  One interesting family that can be seen this time of year are the grebes, aquatic diving birds known for their strong swimming, but not often seen on land or in flight.

Grebes are not ducks, although both are considered to be waterfowl.  They lack webbed feet like ducks, and instead have lobed toes.  Their legs attach further back on their bodies than ducks, making it supremely awkward for them to walk on land. Combined with their lobed toes, however, these attributes make them powerful swimmers and divers for their size.  In our area, there are three species of grebe that can be observed, the Pied-billed Grebe (Podilymbus podiceps), the Least Grebe (Tachybaptus dominicus), and the Eared Grebe (Podiceps nigricollis).

Pied-billed Grebe

The Pied-billed Grebe is a small but chunky waterbird 13.5 inches long that is brownish overall with a blocky head, short thick bill, and almost no tail.  During breeding season, its pale bill has a vertical black stripe, which gives it its name as ‘pied’ means having two or more different colors.  These grebes can trap water in their feathers, giving them control over their buoyancy, sinking deeply or exposing as much or as little of their body as they wish. The Pied-billed Grebe is present year-round, but are more abundant from mid-September to mid-May.  They are not gregarious, so they are often solitary or found in very small groups.

Least Grebe

Least Grebes arrive in central Texas in mid-September, but become scarce by early February.  As the smallest grebe in North America at 9.75 inches long, they have golden yellow eyes, a slim dark bill, are purplish gray in summer, and overall gray brown with a whitish throat and paler bill in winter.  Rather uncommon or local, they can sometimes hide by submerging their entire body under water with only their bill visible.  The Least Grebe is light and has large wings relative to its size, so it can take flight from the water more easily than most other grebe species.

Unlike the previous two grebes, the Eared Grebe is the most abundant grebe species in the world, but it is largely a winter resident in Texas, typically appearing by October and disappearing by May.  It is also a small waterbird at 12.5 inches in length with a bright red eye, very thin bill, and overall dusky brown with white.  In their summer range further north and west, they are black with chestnut sides, and sport golden ‘ears’ or wispy feathers that fan out noticeably from their cheeks behind their eyes. Eared Grebes migrate only at night, and their southward migration in the fall is the latest of any bird species in North America.

The collective noun for a group of grebes is a ‘water dance’, which refers to the fact that they have some of the most elaborate courtship displays of all birds.  Often described as ballet-like, these displays can include bowing, feather fluffing, and rising up nearly out of the water, extending their necks and appearing to run across the water’s surface.  Displays vary and can occur between mated pairs or two competing males, suggesting that they have multiple functions.

Get out this winter and scan the open waters for these beautiful little birds.  While they are not particularly common, nor do we normally see them in the height of their breeding plumage, they are still standouts among the typical rafts of ducks that overwinter in our area. 

Christmas Cactus

The bright red fruits of Tasajillo are present at holiday time, giving 
it an alternate common name of Christmas Cactus.

While many people are familiar with the tropical, non-native species of Christmas Cactus (Schlumbergera sp.) often sold as houseplants, not all are aware that we have a native Christmas Cactus (Cylindropuntia leptocaulis) here in Texas.   Our Christmas Cactus, also called Tasajillo, Pencil Cactus, Christmas Cholla, and Desert Christmas Cactus, is a true cactus much more adapted to our types of soils and climate. Common in the central and western parts of Texas, this plant’s species name, leptocaulis, means ‘slender-stemmed’, and it is a very good descriptor of its form.

Unlike many other cactus species, the flower of our native Christmas
Cactus is small, at only one half-inch across.

Upright, shrub-like, with many branches made up of slender, cylindrical jointed segments, this 2 to 5 foot tall plant is most often found growing in sandy or bottomland soils, having a trunk or main stem up to 4 inches in diameter with thicket-forming stems that exhibit various shades of green and feature a solid, woody internal core.  While occasionally spineless, it typically has very slender, 1-inch grayish-white spines grouped with much tinier spines, along each stem.  Botanists now think that two forms grow in Texas, a ‘long-spine’ form and a ‘short-spine’ form. Its leaves are very small, often not even noticed before they fall early in the growing season.  Small, pale, yellow-green flowers appear at irregular intervals in April/May and July/August, opening in late afternoon or evening.  But the true color display occurs in December, when its fruits turn conspicuously bright red and seemingly cover the plant like it has been festooned for the holiday season.

Christmas Cactus, short-spined growth form.

Christmas Cactus can grow from seed, but it is much more likely to spread by cloning.  The jointed stems can easily detach without harming the rest of the plant, and they are dotted with areoles, a structural feature of cacti that contain buds. All a stem needs to do is come in contact with the right soil, and it can take root and grow a whole new plant.

Christmas Cactus, long-spined growth form.

While the Christmas Cactus can be a nuisance if it develops in the wrong areas, it can also provide desirable value to wildlife and to humans.  Growing best under the protection of other vegetation, it offers dense cover for a variety of nesting birds and provides a good food source for white-tailed deer, bobwhite, wild turkey, most bird species, and many small mammals.  In West Texas, this plant is a larval host plant for the beautiful Staghorn Cholla Moth. From a human perspective, Christmas Cactus has a good ornamental value in a mostly xeric landscape, as it stands out in the bleak winter landscape, adorned with red fruit when most other vegetation is bare.

Staghorn Cholla Moth

Several sources describe the fruits of the Christmas Cactus as edible, even intoxicating.  But they are so small, and the spines so troublesome, that the plant usually yields only a sporadic nibble to the curious human. Nevertheless, native tribes made it part of their traditional diet, noting that the fruits, also called tunas, are vaguely sweet with a taste similar to the fruit of a prickly pear cactus.

Take the time to get to know our native Christmas Cactus and consider adding it to your wildscape.  You will easily learn to fall in love with its prickly nature, especially at Christmas time!

Frost Flowers

Blooming from August to November, Frostweed provides late season nectar
and a unique surprise at the first frost.

Accompanying the crunching of fallen leaves and the rattling of seed pods drying in the breeze is the arrival of the first frost.  This marks the seasonal change from our relatively warm autumn to the cooler days of a mild central Texas winter.  How does frost, this sparkling layer that sometimes covers the fall landscape, form? 

When the temperature of the air reaches a point where the water vapor in it can condense out into water, it is called the dew point.  The frost point is when the dew point falls below freezing, and rather than producing dew, it creates frost.  Consisting of tiny, spike-like crystal structures called spicules that grow out from a solid surface, frost generally forms on surfaces that are colder than the surrounding air.  Even the size of the crystals can vary, depending upon the amount of time they took to grow, the relative changes in temperature, and the amount of water vapor available. 

A frost flower.

Cold air is denser than warm air, so quite often lower areas become colder on calm nights due to differences in elevation.  Known as surface temperature inversion, this phenomenon forms ‘frost pockets’ or areas where frost forms first, due to cold air trapped against the ground.  It is here, in these areas, that you can find a rare and wonderful spectacle of nature called ‘frost flowers.’

While many plants can be damaged or killed by freezing temperatures or frost, this varies by the type of plant and tissue exposed to these conditions.  In central Texas, there is a common plant called Frostweed (Verbesina virginica), which is found in low-lying areas near streams, creeks, canyon bottoms, and in dappled shade at woodland edges. 

Bordered Patch

Silvery Checkerspot

Much of the year, Frostweed goes unnoticed while it grows 5 to 8 feet tall and leafy, the top of each stalk crowned by a cluster of small white flowers.  Its stalks are oddly square-like, with fleshy green flanges. Frostweed begins to bloom in the August heat, and continues until first frost, well into the fall.  These flowers provide late-season nectar for many insects, including bees, beetles, flies, wasps, and even migrating hummingbirds and Monarch butterflies.  It is also a host plant for Silvery Checkerspot and Bordered Patch butterflies.

A patch of frost flowers.

With the first frost, however, the water contained in each Frostweed plant stem expands, causing the stems to crack.  Via capillary action, more water is drawn through the cracks, freezes when it hits the cold air, and forms long curls of ice like petals of a flower, ribbons, or other delicate, abstract sculptures.  Most often, they consist of longitudinal bands of fine ice threads at right angles to the stem.  These delicate flowers of the frost are fleeting in nature, and can only be found in early morning, as the rising temperature quickly melts them away. 

A prime example of crystallofolia.

Only a few species of plants exhibit this unique phenomenon, which has been called ‘crystallofolia’ by Bob Harmes at the University of Texas, from the Latin crystallus or ‘ice’ and folium or ‘leaf’.  Much is left to be discovered reading the purpose of this process, but further research by Dr. James Carter at Illinois State University has concluded that the ice formation often far exceeds the amount of moisture locally available within the plant’s stem, so it must be augmented by water drawn up from the roots.

Delicate curls can form when more plant moisture is available.

On the surface, fall may seem as if nature is shutting down for the winter, but take the time for a second look and you just might be surprised.  The first frost of the season is another intriguing part of the ongoing cycle of life and renewal for our native plants and animals.