Tuesday, March 22, 2011

Red Buckeye

I have a fondness for Red Buckeyes.  They were one of the first wildflowers that I learned to identify in Texas.  They are one of the earliest bloomers along Barton Creek, and they have bright red, tubular flowers that they hold right at eye level, like a trail-side banner announcing the arrival of spring.  Buckeyes also have distinctive, palmately-compound leaves shaped like five-sided stars.  Their leaves emerge even earlier than their flowers, all bright green and shiny and so stiffly-creased that they remind me of newborn horses struggling to stand on all four legs.

Red Buckeye (Aesculus pavia) new spring leaves

I first met the buckeyes, the Aesculus genus, in northern Ohio.  I was an undergrad doing a research project and my mission was to survey the understory plants of floodplain forests.  The problem was that it was winter, and winter in northern Ohio was no joke – biting cold, lots of snow, and not a leaf to be found on any of the young trees that I was trying to identify.  I had to learn to distinguish between the mess of sticks that was the winter forest understory using branching patterns and overwintering buds, and I quickly found that, among temperate trees, alternate branching was more common than opposite branching.  If mycologists had their "LBM's," or little brown mushrooms, so many average-looking, average-size mushrooms, that winter I struggled with the "ABB's," or alternate brown buds, so many alternate-branched trees with frustratingly average-looking brown buds.

What saved me were the opposite-branched trees – the maples, the ashes, and the buckeyes – and their uncomplicated branches.  The Ohio Buckeyes (Aesculus glabra) were particularly easy to spot, with thick, opposite branches and fat, shiny, many-scaled buds that stood out even in the stark Ohio winter.  I am a buckeye, they shouted, and they were common in the most disturbed and saddest floodplain sites that I visited.  They became early friends, lending me a sense of competence long before I could tell an elm twig from a cherry twig just by the angles and lines, and inspired me to keep on with my baggies of twigs and identification keys.

Red Buckeye (Aesculus pavia) overwintering buds

A couple of years later, when I moved to Austin, discovering the Red Buckeyes (Aesculus pavia) along the Greenbelt was a reunion of sorts.  Just as their relatives had in Ohio, the Red Buckeyes stood out in contrast to the late winter landscape, with fat terminal buds that swelled and turned red as the new spring leaves began to emerge.  Even more amazing, these familiar shrubs produced amazingly showy tubular flowers in clusters of red to pink to peach, flowers that I would expect to see on display in a botanical garden, not in flower in early spring in the xeric woodlands of central Texas.  I had trouble believing that these beauties were native wildflowers.

Red Buckeye (Aesculus pavia) flowers

Two varieties of Red Buckeye are native to central Texas – the common, red-flowered variety (Aesculus pavia var. pavia), which grows throughout the southeastern US as a small tree or large shrub, and a yellow-flowered shrub (Aesculus pavia var. flavescens) that is endemic to the western Edwards Plateau.  West of Austin, in the midst of the Hill Country, the two varieties hybridize and form peach- to pink- to orange-flowered varieties.  The showy flowers of both varieties appear in early spring, February to April, attracting hummingbirds, butterflies, and bees.  For me, spring has officially sprung when the buckeyes along the Greenbelt begin to bloom.

This year, the buckeyes began blooming later than usual due to the cold weather of early February, and it took three trips to the Greenbelt over the course of four weeks to document the shift from fat buds to open flowers. In mid-February, when the buckeyes begin blooming in some mild years, the overwintering buds were fattening and becoming more visible against the backdrop of late-winter browns but were showing no signs of opening into leaves yet.

Buckeye buds not yet open (February 19)

By late February, the buds on many buckeye shrubs had begun to open, turning pink as the leaves within began to expand.  On a few of the buckeyes, spring leaves were beginning to emerge, looking newborn, perfectly green, and not yet worn, torn, or faded by the rigors of the upcoming season.

Buckeye buds opening (February 26)

By mid-March, most of the buckeye shrubs had leafed out but were not yet flowering, still waiting for warmer, longer days and a stronger guarantee that the cold of winter was gone for good.

Buckeye after leaf out with flower stalk (March 13)

But a few buckeyes had begun to flower, officially beginning spring at the Greenbelt.  With the start of the central Texas summer less than two months away, that means that this spring, as with most springs, promises to be our shortest, fastest season.

Red Buckeyes begin flowering (March 13)

Thursday, March 3, 2011

First of Spring

Spring is the season of acceleration.  The sun shines warmer, closer, and longer, and the plants respond by growing faster and faster.  If we lived in a more temperate climate, I might have an easier time accepting this speeding up, but in central Texas the first warm day of spring reminds me of the many hot days of summer that are coming, and I can't help but feel a bit of dread as I watch the green of spring quickly overtaking the yellow of my winter-dormant front lawn.

In actuality, my lawn is really more of a mowed weed patch, and only part of the recent green glow is due to spring annuals, like Bedstraw, which looks innocuous now but which will easily take over the shadier parts of my yard in the next month or two.  Also germinating, or sprouting from last year's roots, are hardy perennial weeds like Straggler Daisy, which, once I have pulled or mowed the taller spring weeds, will have regained control of the shady sections of my yard by summertime.  But, while the Bermuda grass smartly waits a few more weeks to break its winter dormancy (if only it were so easy to kill the stuff), the real players in the sunnier parts of my yard are the winter annuals, those quiet, small weeds that germinated between the freezes and waited patiently for this, their moment of sunshine before the big weeds of spring take over.

Shepherd's Purse, a winter annual in the Mustard Family, is a reliable early season weed in my yard and it is easily recognizable by its flowering stalks holding heart-shaped fruits.  (Unfortunately I pulled a patch of them yesterday before thinking to take a picture.)  Henbit, a winter annual from Europe that has made itself at home in yards and disturbed areas throughout the US, also flowers in early spring, covering many lawns in east Austin with its tiny purple flowers.  Up close, Henbit (Lamium amplexicaule) has the attractive, tubular flowers and upright, square stems characteristic of the Mint Family.  Henbit grows close to the ground, making it a nice early-spring ground cover for those of us who aren't concerned about lawn purity, but, for serious lawn growers, I imagine that it is the first enemy of the season.

Henbit (Lamium amplexicaule) in a lawn

The real announcement that spring is here, though, doesn't come from the weeds in the lawn but from the trees above.  The American Elm (Ulmus americana) trees are always the first to bloom, usually in the first week of February.  This year, with our two coldest weeks at the start of February, the elms waited until later in the month.  Their tiny flowers were hardly noticeable except for the faint, green glow on the trees and the first of the spring pollen levels.  After flowering, the elm trees produced loads of light green, wafer-like fruits called samaras.

American Elm (Ulmus americana) samaras

Once they have matured and dried, the elm samaras will carry the seeds of the tree on the wind, much as maple-tree flyers (also a type of samara) do.  But for now, while the elm trees are covered in the young, green samaras of early spring, they are the most visible trees in the neighborhood, highlighted in the green glow of spring long before the surrounding trees have begun to leaf out.

American Elm (Ulmus americana) covered in samaras

While the elm trees are lit up in green, the cherry and plum trees of the area are covered in white flowers that are sweet-smelling as well as attractive, much to the delight of many nectar-starved bees, flies, butterflies, and wasps.  In the weeks right after the late-season freezes, the honeybees were so desperate for food that I was regularly finding them in my kitchen, drinking from the dish sponge, so it is a relief to see them employed again, happily buzzing from one spring blossom to another.

Cherry or plum tree (Prunus sp.) in flower

Two native species of plums, Mexican Plum (Prunus mexicana), a small tree common along waterways, and Creek Plum (Prunus rivularis), a thicket-forming shrub, contribute to the early-spring show of white flowers in and around Austin, but in town many ornamental species of plum and cherry also bloom at the start of spring, making identification difficult.  Plum and cherry trees bloom in clusters of white flowers that appear before the leaves or just as the leaves are opening.  Their flowers are five-petaled, with the many stamens and the radial symmetry characteristic of Rose Family flowers.

Cherry or plum (Prunus sp.) flowers

Texas Redbud (Cercis canandensis var. texensis) is a small, Pea Family tree that also blooms in the early spring, before its heart-shaped leaves expand.  Its rose-purple flowers decorate yards, parks, and wild spaces throughout Austin from late February and to early April, attracting bees, butterflies, and moths.  Texas Redbud is a drought-tolerant variety of the Eastern Redbud (Cercis canadensis) that is adapted to the limestone soils of the Edwards Plateau. 

Texas Redbud (Cercis canandensis var. texensis) flowers

The beauty of spring is in the stark contrast, of spring green in an otherwise brown landscape, or of bright white or purple against a deep blue sky.  To appreciate it, I had to get out in it, to feel the warmth of the sun and to smell the plum blossoms.  Then I got my shovel and gardening gloves and did some digging and weeding on the south side of my house, where the afternoon sun is concentrated.  Out in it, with my hands in the soil, my sense of dread, that spring and summer and all the planting deadlines in between are looming, finally faded away.  Because spring, short and fast as it is in central Texas, is a season of doing, not of worrying about the summer to come.