Tuesday, July 3, 2012

June at the Greenbelt

The water is all but gone now, reduced in a matter of weeks from a flowing creek to a dry creek bed with a few muddy spots and murky pools, the largest and most lasting of which is the pond formed by the springs just downstream of Sculpture Falls.  The only place where a dog can get wet in the hot, dry years.  I was hoping that this wouldn't be one of those years, just as I did not welcome the return of record-breaking temperatures – I would've been happy to skip a year, or ten, in pursuit of the hottest June day ever – but at least we had the spring rains and, because of them, several weeks of (early) summer creek flow on Barton Creek.

Our wildflowers are adapted to this nonsense.  The spring bloomers, like Bluebonnets and wild mustard, are winter annuals that germinate in the fall, grow in the early spring, and bloom in late spring, completing their life cycle within the cool season.  The early summer bloomers, a mix of winter annuals like Indian Blanket and perennials like Winecup, similarly get their business of blooming done before the real heat of summer.  The fall bloomers, like Golden-Eye and Agalinis, grow in the spring, wait out the summer in near stasis, then bloom in the fall, once the heat of summer has passed.  And the few wildflowers remaining, the brave all-summer-long bloomers, take their cues from the weather as well, blooming sporadically from April to October, whenever we happen to get the rain.

So early June at the Greenbelt, with the water still running but not for much longer, was an ideal place to see wildflowers in bloom, a mix of annuals just this side of going to seed, perennial shrubs and vines flowering in the less stressful part of summer, and all-summer-long bloomers taking advantage of the moisture lingering in the ground around the creek.  Knowing that the water was waning, Lee and I headed to the upstream part of the Greenbelt trail to enjoy the end of the season.  Though it is counter-intuitive, Barton Creek dries up in its downstream stretches first, so when the creek bed is dry downstream of the Loop 360 overpass, water may still be flowing upstream of the Mopac overpass.  We started our walk even farther upstream, at the end-of-trail entrance, hiking down the long hill.  At the bottom of the hill, in an open field on the way to the uppermost falls, was a huge display of red and yellow and purple wildflowers.

Field of Indian Blanket, Mexican Hat, Brown-Eyed Susan, and Purple Horsemint

The dominant red and yellow flower in the field was Indian Blanket, a common Sunflower Family wildflower in Texas.  With yellow disc flowers (the center of the sunflower) that turn red as they bloom and red ray flowers (the part of the sunflower that looks like the petals) with yellow tips, the inflorescence of Indian Blanket looks like a red and yellow bulls-eye.  Indian Blanket (Gaillardia pulchella) is an annual that reseeds readily, forming huge colonies in open fields and along our roadways in the late spring.

Indian Blanket (Gaillardia pulchella)

The other red and yellow flower in the field was Mexican Hat, another common Sunflower Family wildflower.  The ray flowers of Mexican Hat are red with yellow and tend to droop downward, while the green to brown disc flowers form a tall column, giving the inflorescence a hat-like shape.  Mexican Hat (Ratibida columnaris) is a bushy, drought-tolerant biennial or perennial that grows on roadsides and in abandoned fields, blooming from April to July.

Mexican Hat (Ratibida columnaris)

The balance of yellow in the field of wildflowers was contributed by Brown-Eyed Susan.  Like Indian Blanket, Brown-Eyed Susan is annual in the Sunflower Family that forms huge, showy colonies in open, grassy areas.  The disc flowers of Brown-Eyed Susan are purple-brown while the ray flowers are yellow with a red-brown spot at the base of each and tend to droop downward.  Brown-Eyed Susan (Rudbeckia hirta) prefers sandy or limestone soils and blooms from April to July.

Brown-Eyed Susan (Rudbeckia hirta)

The purple flowers in the field were those of Purple Horsemint, another common wildflower that is known for its large, picturesque colonies.  The pink to purple flowers are two-lipped and spotted, whorled together into a dense inflorescence of flowers and bracts (the leaves beneath each flower) that are also purple.  Purple Horsemint (Monarda citriodora) blooms from May to June, and its flowers turn more whitish-purple toward the end of the bloom.

Purple Horsemint (Monarda citriodora)

The uppermost falls, usually a quiet spot for hot cyclists, older couples, and happy dogs, was crowded with the young sunbathers that usually gather at Twin Falls, confirming that the creek was indeed drying up downstream.  We crossed the creek above the falls and headed downstream along the trail.  This shady section of the trail, sandwiched between the creek and a slope forest, was still cool and moist, hanging onto the last of spring.

Along the trail, American Beautyberry shrubs were in flower.  American Beautyberry (Callicarpa americana) is a large shrub that is common throughout the southeastern United States.  At the eastern edge of its range in central Texas, it is mainly found along streams and in moist bottomlands.  While the purple berries of Beautyberry are a stand-out feature of the Greenbelt trail in the fall, the bunches of tiny pink-purple flowers that appear on the shrubs in May and June are easier to miss.

American Beautyberry (Callicarpa americana)

Thoroughwort, a smaller shrub in the Sunflower family that tends to grow on the rocky hillsides above the trail, was also in bloom.  Thoroughwort (Ageratina havanensis) is a perennial shrub that blooms on and off all summer, its flowers suspended on branches that seem to grow straight from the rocks on the cliff side of the trail.  The leaves of Thoroughwort are deltoid, or arrow-shaped, and the flowers are white, grouped together into inflorescences that look like miniature white pom poms.

Thoroughwort (Ageratina havanensis)

On the creek side of the trail, growing at the water line along a deeper, slower section of the creek, Buttonbush was also in bloom.  Buttonbush is a large, many-branched shrub that grows along streams, lakes, and ponds, blooming in the summer.  The leaves of Buttonbush (Cephalanthus occidentalis) are large and oval-shaped and the inflorescence is an off-white globe of flowers with long stamens that extend past the petals.  After flowering, the inflorescence dries into a brown ball of seeds ready to float downstream in the next flood.

Buttonbush (Cephalanthus occidentalis)

Also growing close to the creek, tangled in shady patch of understory, was the Snapdragon Vine.  The shiny leaves of the Snapdragon Vine look like those of English Ivy, a cross between a triangle and a heart, while the flowers have five, fused petals that are light violet to dark purple with white centers.  Snapdragon Vine (Maurandya antirrhiniflora) grows on rocky, limestone soils of the southern Hill Country and blooms after rains from March to September.

Snapdragon Vine (Maurandya antirrhiniflora)

Farther downstream, after passing the two mini falls, the trail moved away from the creek into a flat, wooded-to-open floodplain where Texas Lantana (Lantana horrida) was blooming in half-shady places.  Texas Lantana is a tough, drought-tolerant shrub that grows all over Austin, blooming in yellow and red-orange flowers all summer long, rain or not.  Lantana has square, rough-to-prickery stems and a strong aroma that I associate with the heat of summer.  I have trouble enjoying Lantana because of its commonness and because it grows wild along the south side of my house, where I can't decide if it is a weed or a wildflower.  But its flowers, grouped into round clusters, are bright and striking, and the plants seem to thrive on blazing heat and baking drought, qualities that are hard not to appreciate.

Texas Lantana (Lantana horrida)

The upstream section of the Greenbelt was surprisingly crowded that day, especially for a weekday, with crowds of swimmers at each falls, however minor, again reminding us that the season was about to be over.  Eventually, Lee and I found a couple of quiet places to get into the water before reaching Sculpture Falls, where we crossed to the main trail on the other side of the creek and headed back upstream.  Before long, a shady, tree-lined section of the creek lured us back to the water, where I found, beneath the warm water, active springs of cold water, and, around the corner, a murky backwater section of the creek that was overgrown in Dodder.  Dodder (Cuscuta sp.) is a parasitic vine in the Morning Glory Family that twines its yellow stems around its host plant.

Dodder (Cuscuta sp.) growing on plants in the creek

While Dodder, with its non-photosynthetic yellow stems, represents the darker side of the twining habit, literally living off its host plants, the Purple Leatherflower, a climbing vine that is a rare treat to find growing in the understory along streams in our area, represents the refined side, a vine that would be just as welcome in a garden as in the woods.  Purple Leatherflower (Clematis pitcheri) has shiny, lobed leaves and thick, bell-shaped, purple flowers that appear in May and June.

Purple Leatherflower (Clematis pitcheri)

The trail on the east side of the creek was wider, higher above the creek, and more exposed to the afternoon sun than the trail on the west side had been.  In those drier conditions, Turk's Cap, a shrub in the Hibiscus Family, was blooming in the shade of cedar trees.  Turk's Cap (Malvaviscus arboreus var. drummondii) is an herbaceous perennial that regrows from the ground each year, aggressively forming thick colonies in the shade of woods nears streams.  The flowers of Turk's Cap are bright red, with upright petals that remain half-closed and a column of fused stamens that rises above the petals.  The staminate column, also bright red, is decorated, on the sides, with the yellow ends of the stamens (male parts) and, on the top, the red stigmas (female parts) of the flower.  Turk's Cap is one of our all-summer-long bloomers, making flowers from June through October that turn into round, red fruits.

Turk's Cap (Malvaviscus arboreus var. drummondii)

Velvet-Leaf Mallow, another shrub in the Hibiscus Family, was also in bloom.  Velvet-Leaf Mallow (Allowissadula holoserica) is a woody perennial that grows on dry, rocky soils of the Edwards Plateau.  Velvet-Leaf Mallow has toothed, heart-shaped leaves with wooly margins and flowers with five orange-yellow petals.  Velvet-Leaf Mallow produces flowers all summer, providing food for butterflies.

Velvet-Leaf Mallow (Allowissadula holoserica)

As the trail neared its upstream end, we returned to the territory of heat-loving sunflowers.  Part way up the long hill to Scottish Woods, a colony of blooming Nerve-Ray gave me an excuse to stop for a photo break.  The inflorescence of Nerve-Ray looks something like that of Echinacea, with narrow, yellow ray flowers that are widely spaced around a reddish-brown sphere of disc flowers.  Nerve-Ray (Tetragonotheca texana) gets its genus name (tetragon-) from its four-sided involucre, the green, fused leaf beneath the inflorescence.  Nerve-Ray is a bushy, many-branched shrub that grows on rocky soil in the southern Hill Country, blooming from April to September.

Nerve-Ray (Tetragonotheca texana)

Growing closer to the ground, its stems mixed with grasses midway up the hill, was Zexmenia, another bright yellow sunflower.  Zexmenia (Wedelia texana) is a perennial shrub that is woody at its base with herbaceous stems that hold the yellow, Cosmos-like flowers high above the low-growing plant.  Zexmenia blooms from May to September and is a host to native butterflies.

Zexmenia (Wedelia texana)

At the top of the hill we walked back into the city, happy for the swim but sad that the season was ending.  Though I have been in Austin for fifteen years, I still have to remind myself that "summer," in the up-north sense of summer as the peak growing season for plants, is a broken season in central Texas.  Summer begins in April, is suspended in June, resumes in September, and ends in October.  We are currently suspended, stranded in a three-month hiatus from summer.  Annual plants are done for the year and the perennials are in survival mode, waiting until ground-soaking rains break the hiatus.  Which could happen next week or in October.

I am, as usual, a bit stunned to be here.  Like a gambler who always thinks that this round will be the one, I am perpetually convinced that this summer will be the one that isn't broken, the one that is kept whole, or is at least extended a month or two, by summer thunderstorms.  It has happened before.  But I've been here long enough to expect nothing less than blazing heat.  So, as I arrive here yet again, I have to appreciate the native wildflowers and their ability to make a life between, before, around, or straight through, our broken summers.  One of these years, I'm going to figure out how to follow their lead.  Until then, here's to enjoying the water while it lasts.

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