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Monday, March 11, 2019

Plant Natives!

Non-native, invasive, Nandina - Please avoid planting this and consider removing it from
your landscape.  It is a pest in our parks and preserves.
Spring is the ideal time to think about planting, and how you manage your garden or landscape can have an effect on the overall health of the soil, air, water and habitat for native wildlife as well as our human community. Help conserve and improve the quality of these resources by using sustainable gardening practices such as mulching and composting, reducing or eliminating lawn areas, xeriscaping (planting native, drought-tolerant plants), installing rain barrels, and removing non-native invasive plants and restoring native ones.

The U.S. government defines an invasive plant species as one “that is not native to the ecosystem under consideration and whose introduction is likely to cause economic or environmental harm or harm to human health.” These species grow outside desired boundaries, out-competing native species, and spread by seeds, berries, spores, runners, rhizomes, and stems. Some can be easily transported long distances, and every year millions of our tax dollars and thousands of volunteer hours are spent trying to eradicate them.

Many of these plants have already invaded our preserves and greenbelts in Austin, originating in our landscapes, escaping cultivation and spreading into the wild. Invasive species may grow faster, taller, or wider and shade out native species. Many stay green later into the season or leaf out earlier, giving them an advantage over natives. They can change the vertical and horizontal structure of ecosystems, alter hydrology, and disrupt nutrient cycles, all of which can have devastating effects on native plants and animals.

Although invasive exotics may offer birds fruit, squirrels nuts, and hummingbirds and butterflies nectar, they do not provide the entire range of seasonal habitat benefits that an appropriate locally native species will provide. If we want not only to satisfy our desires to attract wildlife, but also to restore the critical, often unseen, small pieces in our ecosystems, we need to bring back our locally native plants. These plants are not only attractive to humans, they also meet the food and cover needs of all wildlife species: bees, wasps, butterflies, grasshoppers, bugs, beetles, spiders, and thousands of others that sustain and support food webs which songbirds, salamanders, bats, toads, and box turtles more visibly demonstrate.

Escarpment Black Cherry is a beautiful native tree that makes a great replacement for the

highly invasive privets or ligustrums.
Aside from attracting a diversity of wildlife, the use of native plants minimizes the impact our landscapes have on the natural environment around us. They reduce water consumption, eliminate the need for chemical fertilizers and pesticides, and limit the competition from invasive exotics. This results in a much healthier habitat—water, soil, and air—for humans and animals alike, and is less costly, too. Invite wildlife to put on a show in your backyard by replacing the invasives in your landscape, and encourage your neighbors to do the same.

Non-Native/Invasive Plant(s)
Some Native & Adapted Alternative(s)
Wax Myrtle (Morella cerifera)
Yaupon Holly (Ilex vomitoria)
Bamboo Muhly (Muhlenbergia dumosa)
Chinquapin Oak (Quercus muehlenbergii)
Texas Red Oak (Quercus buckleyi)
Chinese Tallow Tree 
Bigtooth Maple (Acer grandidentatum)
Lacey Oak (Quercus laceyi)
Elephant Ear
Arrowhead (Sagittaria latifolia )
Crinum Lily (Crinum americanum)
Pigeonberry (Rivina humilis)
Frogfuit (Phyla nodiflora)
Horseherb (Calyptocarpus vialis)
Giant Cane
Roughleaf Dogwood (Cornus drummondii)
Yaupon Holly (Ilex vomitoria)
Japanese Honeysuckle
Coral Honeysuckle (Lonicera sempervirens)
Passion Vine (Passiflora foetida or incarnate or lutea or tenuiloba)
Rock Rose (Pavonia lasiopetala)
Holly Fern
River Fern (Thelypteris kunthii)
Kudzu, English Ivy, Vinca
Virginia Creeper (Parthenocissus quinquefolia)
Trumpet Vine (Campsis radicans)
Coral Vine (Antigonon leptopus)
Ligustrum (all species) or Common Privet
Evergreen Sumac (Rhus virens)
Barbados Cherry (Malpighia glabra)
Yaupon Holly (Ilex vomitoria)
Possumhaw Holly (Ilex decidua)
Texas Sage (Leucophyllum frutescens)
Cherry Laurel (Prunus caroliniana)
Black Cherry (Prunus serotina)
Desert Willow (Chilopsis linearis)
Texas Redbud (Cercis canadensis var. texensis  )
Elbowbush (Forestiera pubescens )
Nandina or Heavenly Bamboo
Texas Lantana (Lantana urticoides)
Bush Germander (Teucrium fruticans)
Texas Sage (Leucophyllum frutescens)
Paper or White Mulberry
Red Mulberry (Morus rubra)
Texas Persimmon (Diospyros texana)
Possumhaw Holly (Ilex decidua)
Cherry Laurel (Prunus caroliniana)
Yaupon Holly (Ilex vomitoria)
Possumhaw Holly (Ilex decidua)
Evergreen Sumac (Rhus virens)
Red-tipped or Chinese Photinia
Evergreen Sumac (Rhus virens)
Carolina Buckthorn (Frangula caroliniana)
Yaupon Holly (Ilex vomitoria)
Russian Olive
Texas Persimmon (Diospyros texana)
St. Augustine Grass
Buffalo Grass (Bouteloua dactyloides)
Tamarisk or Salt Cedar
Bald Cypress (Taxodium distichum)
Arizona Cypress (Cupressus arizonica)
Tree of Heaven
Chinquapin Oak (Quercus muehlenbergii)
Lacey Oak (Quercus laceyi)
Vitex or Chastetree
Texas Pistachio (Pistacia mexicana)
Mexican Buckeye (Ungnadia speciosa)
Passion Vine (Passiflora foetida or incarnata or lutea or tenuiloba)
Trumpet Vine (Campsis radicans)

Tuesday, February 12, 2019

Early Spring Heralds

Windflower, typical white form
February is a time of change in Central Texas, with temperatures often ranging from the 30s to the 70s, and it is precisely these large swings in temperature that create challenges for local wildlife. Finding food is essential, and the little things like insects that emerge in early spring rely heavily on the early bloomers in our native landscape.

Elbowbush (Forestiera pubescens), also commonly called Stretchberry or Spring Herald, is a multi-branched deciduous shrub with smooth gray bark, long arched branches, and light green leaves.  It is most conspicuous, though, in late January and early February, when small, yellow-green, petal-less flowers begin to burst in small clusters on the bare twigs. Common in open woodlands, brushy areas, and near streams, its early flowering period provides nectar for native bees and spring butterflies, namely Gray, Juniper, and Great Purple Hairstreaks.  Elbowbush gets its common name from branches that typically form in right angles to one another, reminiscent of a bent elbow.  It produces a quarter-inch, fleshy, dark blue fruit often devoured by wildlife in the summer, and its leaves turn a unique chartreuse color in the fall.  Additionally, Elbowbush is one of the larval food plants for the Incense Cedar Sphinx (Sphinx libocedrus). 

Two-flowered Anemone, exhibiting side stem
Poking their colorful blooms above the drab winter landscape are two species in the Buttercup Family,  Two-flowered Anemone (Anemone edwardsiana) and Windflower (Anemone berlandieri). While both of these plants bloom from February to April, Two-flowered Anemone is an uncommon plant that is also called the Edwards Plateau Thimbleweed, since it grows only in this region of Central Texas.  Windflower is common and has a more widespread range, and is often called Southern Anemone or Tenpetal Anemone (even though it can have 10 to 20 petal-like sepals).

Two-flowered Anemone, deep blue form
Two-flowered Anemone grows 6 to 12 inches tall, and is most often found on the moist banks of shaded canyons.  Midway or further up the stem are three bracts, with side stems growing from those bracts, and each side stem can produce 1 to 3 flowers, with only 1 flower on the main stem. In reality, most plants carry only 2 or 3 flowers in total, each 0.5 to 1.25 inches wide and typically white, but can exhibit pink, lavender, light blue, or deep blue. In comparison, Windflower grows 6 to 15 inches tall, with low-lying leaves that are divided into three segments and are often reddish-purple on the underside.  Its single stem carries only 1 flower, 0.75 to 1.5 inches wide, and it can exhibit the same range of colors as the Two-flowered Anemone. 

Windflower, pink form
Windflower, light blue form
Found on the moist soils in shaded canyons in the southern half of the Hill Country, Golden Groundsel (Packera obovate) is a rosette-forming perennial that blooms from February to April. Slender flowering stems rise up to 18 inches above the basal rosette of oval leaves, topped with yellow flower clusters few to many-headed, with each flower 0.5 to 0.75 inches wide.  Once established, this plant colonizes quickly, and can create an early-blooming, evergreen ground cover in shady, woodland areas.

Golden Groundsel
Why not plant some these early bloomers in your landscape, as they not only provide early nectar for bees and butterflies, but they are also heralds of our coming spring!

Friday, January 18, 2019

Bag Ladies

Bagworm on Crepe Myrtle

While winter is the time of year when we hang man-made ornaments on our trees and shrubs to commemorate the holiday season, it is also the time of year when nature-made ornaments are most apparent in the landscape.  These ornaments are as widely unique as snowflakes, and their appearance varies with the bits and pieces of leaves, twigs, and bark fragments woven into silken bags in a shingle-like fashion.  They reveal themselves on the bare branches and limbs in winter, and they are created by female bagworms.

Bagworm on Anacacho Orchid Tree

Members of the Psychidae family, there are about 1,350 species of bagworms worldwide, also commonly known as bagworm moths or bagmoths. Although different bagworm species vary slightly in habits and life cycle, bagworms spend the winter months in the egg stage sealed within the bags produced by females the previous fall.  

In late May to early June, very tiny caterpillars hatch, produce a silken strand by which the wind can carry them to new foliage (called 'ballooning'), and construct a tiny conical bag carried upright with them as they move.  During leaf-feeding, the caterpillars emerge from the top of the bag and hang onto the host plant with their legs, sometimes aided with a silken thread. The bottom of the bag remains open to allow fecal material (called ‘frass’) to pass out of the bag. 

By August or September, fully grown caterpillars have developed larger bags, and pupate within them.  Seven to 10 days later, the pupae of the male moths work their way out of the bottom of the bag, and emerge from their pupal skin.  These males have half-inch long clear wings, feathery antennae, hairy black bodies, and they spend their time seeking out a female to mate.  Females, on the other hand, are immobile and stay in the larval stage, do not develop into moths, and remain inside the bags. After mating, the females produce a clutch of 500 to 1000 eggs inside their bodies and then die.    

Bagworm on Juniper

Bags vary in size, up to 2 inches long and about a half inch wide, and are spindle-shaped.  They can be quite ornamental, covered in a somewhat patterned array of bits and pieces of plant matter.  A wide range of broadleaf and evergreen trees and shrubs serve as hosts for bagworm species, including juniper, cedar elm, bald cypress, live oak, persimmon, sumac, sycamore, willow, yaupon, and native fruit and nut trees.  

Since these bags are composed of silk and plant materials, they are naturally camouflaged from predators such as birds and other insects.  While birds can eat the egg-laden bodies of female bagworms after they have died, the eggs are very hard-shelled and can pass through the bird's digestive system unharmed.  This represents yet another way to disperse bagworm species over a wide-ranging area, and helps in creating a whole new generation of bag ladies!

Saturday, December 29, 2018

The Simple Beauty of Sparrows

White-crowned Sparrow, Zonotrichia leucophrys

Coming from the Anglo-Saxon word ‘spearwa’ and literally meaning ‘flutterer’, sparrows often conjure up images of the ubiquitous and non-native House sparrow and the House finch, which isn’t a sparrow at all.  While most sparrows are generally small to medium brown birds with streaks, the differences between sparrows can best be determined by their relative size, head markings, and habitat.

White-throated Sparrow, Zonotrichia albicollis

All sparrows have conical bills that they use to shell seeds, a primary component of their diet year-round, but especially so in the winter months.  There is little difference between the males and the females in terms of appearance, but males are on average larger than females.  As a group, most sparrows are birds of grasslands, prairies, and marshes, and seem to prefer weedy fields and woodland edges in the winter.  Of the sparrow species that migrate, none travel further than the southern United States or northern Mexico.

Chipping Sparrow, Spizella passerina

One of our most common winter sparrows is the Chipping sparrow.  Small and slim, with a long notched tail, rusty cap, white stripe over the eye and a black line through the eye, this sparrow moves in loose flocks and frequently feeds in short grass and open woods.  While still fairly abundant, this sparrow is declining in numbers, mainly due to habitat destruction, and winters in the southern part of the United States.  When first identified in 1810 by an American ornithologist, it was nicknamed ‘the social sparrow’ for it was easily approached and associated with human habitation.

White-crowned Sparrow, Zonotrichia leucophrys 

A fairly large sparrow, the White-crowned sparrow is distinguished by its black and white striped head, unmarked gray breast, and dark pink bill.  It is found in large groups in thickets and weedy areas, foraging on the ground.  Discovered in 1772 by a German naturalist, this sparrow was originally named the ‘white-eyebrowed bunting’, for in the Old World, sparrows were usually called buntings. 

Found in a variety of grassy habitats, and often in small flocks, is the Savannah sparrow. Streaked on both their back and their breast, Savannah’s have pink legs, yellow above the eye, a thin white median crown stripe, and a short notched tail.  First described by a British ornithologist in 1790, it was called a ‘sandwich bunting’ due to the first specimens being collected from Sandwich Bay in the Aleutian Islands of Alaska.   

Lincoln's Sparrow, Melospiza lincolnii

Lincoln’s sparrow is a medium-sized bird with a rather short tail, broad gray stripe above the eye, buffy moustache stripe, and a buffy upper breast with crisp, blackish streaks.  Found in winter in brushy edges of ponds and other moist areas, this sparrow was named by John James Audubon in 1833 after his research companion, Thomas Lincoln, shot the first specimen in Labrador.       

Sparrows are gregarious and are often our most hardy winter visitors.  Adorned in various shades of brown, gray, black, and white, they reflect the subdued hues of a winter landscape.  Often dismissed as ‘little brown birds’ when seen with the naked eye, these birds invite closer inspection and are nature’s way of reminding us that subtle colors and patterns can be beautiful, too!   

Wednesday, November 7, 2018

Whorled Wonders

Great Plains Ladies Tresses

The spiral, which is a fundamental form in nature, is most splendidly illustrated in a genus of wild, native orchids called Spiranthes.  Commonly known as ladies tresses, the genus name comes from the Greek speira meaning ‘coil’ and anthos meaning ‘flower’, and refers to each species spirally arranged inflorescence.  The most predominant species of orchid found in Texas prairies, several members of this genus are colonizers of sparsely vegetated areas, appearing on newly disturbed sites such as roadsides and cleared fields, increasing in number until outcompeted by other vegetation.

Of the 15 native Spiranthes species in Texas, several are so similar in appearance that either a hand lens or microscope is often needed to distinguish one from another. To add to the confusion, many closely related species are also known to hybridize. However, Central Texas, the most common include the Great Plains Ladies Tresses (S. magnicamporum) and the Nodding Ladies Tresses (S. cernua).  

Great Plains Ladies Tresses has 2 to 4 narrow, grass-like basal leaves, up to 6 inches long, that are usually absent or withering during the flowering period.  The flower spike can range from 4 to 24 inches tall, and is made up of 12 to 54 small white tubular fragrant flowers, tightly or loosely spiraled, that nod abruptly from the base.  Blooming from September to November, it prefers calcareous grassland habitat, often growing in association with our native Seep Muhly.  In wet years, this orchid may appear in robust spikes numbering in the hundreds, and in dry years it may not flower at all.

Nodding Ladies Tresses has 3 to 5 narrow, grass-like, basal leaves, 8 to 10 inches long, and are typically present at flowering.  It has a flower spike that can grow from 4 to 19 inches tall, and consists of 10 to 50 small white tubular flowers, tightly or loosely whorled in 2 to 4 rows along the upper portion of the stem.  Blooming from late September through November (and sometimes even into December), it can grow on wet or dry sites, but prefers more acidic, sandy soils.

Flowers of Spiranthes orchids begin opening at the bottom of the inflorescence.

Like most orchids, the flowers of these Spiranthes species are resupinate, or twisting during development into an upside-down position.  In fact, the tendency of the flowers to droop slightly gives the Nodding Ladies Tresses both its common and species name, for cernua comes from the Latin and means ‘drooping.’  Unlike other closely related species, the flowers of the Nodding Ladies Tresses have little or no fragrance, but like other closely related species, the flowers are pollinated by bumblebees.  As with most Spiranthes, bumblebees start at the bottom and move upward on the inflorescence in search of nectar. Older flowers at the base of the flower stalk have more nectar, which makes them an efficient first stop for the foraging bumblebees.

As mentioned above, many Spiranthes are difficult to identify to species, and both the Great Plains Ladies Tresses and the Nodding Ladies Tresses are no exceptions.  In fact, Nodding Ladies Tresses is known as a compilospecies, which is defined as a genetically aggressive species that incorporates the heredities of a closely related species by hybridization through unidirectional gene flow, and may even completely subsume that species over time.  Now that’s a whorled wonder!

Saturday, November 3, 2018

Silent Flight

Eastern Screech-Owl
Owls have fascinated man from time immemorial – to some cultures they are symbols of wisdom, while to others they are harbingers of doom and death.  Adding to the mystique of these creatures is that they are mainly active at night, using their exceptional vision, acute hearing, and silent flight to stealthily hunt down their prey.

Common in Central Texas, the Eastern Screech-Owl is found in wooded suburban and rural areas and readily nests in tree cavities as well as man-made nest boxes.  A small owl 6-10” long with a wingspan of 19-24”, it has feathered ear tufts and is normally gray, brownish-gray, or less commonly reddish-brown.  The Eastern Screech-Owl eats a variety of small animals, and each night consumes from one-quarter to one-third of its own body weight.  It uses a soft trilling call to keep in contact with a mate or family members, and the male’s trill can advertise a nest site when courting a female or signal an arrival at the nest with food.  This owl also has a descending whinny, which is used to defend its territory.  Eastern Screech-Owl pairs are usually monogamous and remain together for life, although they will take a new mate when one dies.  In mid-April, the female lays 3-4 eggs on average, and the downy white owlets emerge from the nest by mid-May.

Great Horned Owl
Also common but much larger at 18-25” long with a wingspan of 40-57”, the Great Horned Owl prefers habitats of secondary-growth woodlands mixed with open meadows.  Often found perching next to an open area and nests in tree hollows, broken off snags, or nests made by other large birds.  It has prominent ear tufts spaced widely on its head, a brownish-gray body with dark barring, and a rusty facial disk edged in black surrounding each of its orange-yellow eyes. The Great Horned Owl has a broad diet of small mammals, birds, amphibians, and reptiles, and is the only animal the regularly eats skunks.  They have a large repertoire of sounds, but the most common is that of the male’s resonant territorial call ‘hoo-hoo hoooooo hoo-hoo’ that can be heard over several miles through the canyons on a still night. These owls are solitary in nature, only staying with their mate during the nesting season of January and February. Typically 2-4 eggs are laid and incubated solely by the female, until the young start roaming from the nest six to seven weeks later.  

The structure of an owl’s feather is the main reason they can fly so silently.  The leading edge of their primary wing feathers are serrated like a comb, which breaks down the turbulence into smaller, micro-turbulences.  The soft, tattered edges of their secondary feathers allow those small currents of air to pass through them and further reduce the turbulence behind their wings.  In addition, the velvety down feathers found in the wing linings and on their legs further dampen and absorb sound frequencies.  Together, these features allow the owl to greatly reduce the overall noise caused by the turbulence of air flowing over them as they fly.  

Thursday, October 4, 2018

Astonishing Acorns

Texas Red Oak is one of many types of oaks that produce
acorns in autumn
Famous for its oak trees, there are more than 50 species of oak native to Texas.  In our region of Central Texas, some of the most common include Live Oak (Quercus virginiana), Texas Red Oak (Quercus buckleyi), and Bur Oak (Quercus macrocarpa).  

A familiar tree with a stately growth habit, Live Oak is commonly 50 feet tall but with several large, twisting limbs that form a low, dense crown that can spread over 100 feet.  Its leaves are oblong in shape, leathery, 2 to 4 inches long and 0.5 to 2 inches wide.  Slow-growing but long-lived, it appears to be evergreen rather than deciduous since its old leaves fall just as new leaves emerge in the spring.  The annual acorns of this tree are dark brown and shiny, about 1 inch long and 0.5 inch wide, half covered in a gray, downy cup borne on a long stem. 

Live Oak Acorns
Texas Red Oak, also called Spanish Oak or Buckley Oak, is a small to medium tree to 35 to 70 feet tall, and its habitat is restricted to limestone ridges, slopes, and creek bottoms.  Its leaves are deeply lobed and it provides good shade in the summer and deep red color in the fall.  Its acorns are biennial, or maturing every other year, but when they do occur they are plentiful.  They can occur singly or in pairs, are up to 0.75 inches long and 0.5 inches wide often streaked with dark lines, and set in a shallow cup covering one-third to one-half of the fruit.

Texas Red Oak Acorns
A large, deciduous tree reaching a height of 80 feet or more, the Bur Oak has heavy branches that form an open, spreading crown, and leaves with highly variable lobes that can grow to 12 inches long and 6 inches wide.  But what is most characteristic is its’ distinctively large annual acorns, up to 2 inches long, set into a deep mossy-fringed cup that gives this species its common name.  In fact, an alternate common name is Mossycup Oak.  Bur Oaks have a medium growth rate, and develop a deep taproot that allows them to draw water and anchor the tree, even in drought conditions.

Bur Oak Acorn
The origin of the word acorn is dubious, as several sources are possible including Old Norse akarn meaning ‘fruit of wild trees’, Gothic akran meaning ‘fruit’, and Old English aecern meaning ‘mast or oak-mast.’  Mast is a term often applied to the fruit of oak trees, especially when they are used as food source for animals.

In Texas, oaks are important trees for wildlife as they provide acorns for food, shelter in their huge branches, and both food and shelter as they slowly decay.  For humans, oaks protect against soil erosion, buffer homes from strong winds, and provide true beauty in the landscape.  All of these benefits are derived from the simple yet astonishing acorns!