Beat the Heat

 

Flame Acanthus is a hot weather bloomer.

The heat of the Texas summer is enough to make everything wilt, but there are some native plant species that truly thrive in these unrelenting temperatures and drought-stricken conditions.  These plants include Turk’s Cap (Malvaviscus arboreus var. drummondii), Flame Acanthus (Anisacanthus quadrifidus var. wrightii), Violet Ruellia (Ruellia nudiflora), and Western Ironweed (Vernonia baldwinii).

Turk’s Cap, also known as Drummond’s Turk’s Cap, Wax Mallow, Mexican Apple, Manzanita, and Sleeping Hibiscus, is a spreading shrub to 4 feet high, with large green leaves on upright stems.  Bright red flowers atop the stems are twisted into a whorl from which protrude red stamens.  These flowers are a natural source of nectar for hummingbirds and butterflies, and it is a host plant for the Turk’s-cap White-Skipper butterfly.  The resulting fruit is red and marble-sized, and edible for animals and humans alike. Turk’s Cap is the perfect plant to grow under trees that tend to shade out non-native turf grasses, as they form a natural cover and provide much needed color from May all the way to November.

Turk's Cap

Turk's Cap fruit

Turk's-cap White-Skipper

An airy, spreading shrub to 5 feet tall, Flame Acanthus has tender lance-shaped green leaves and tubular red flowers that open to 4 lobes and occur along terminal spikes.  Blooming in full sun from June to October, it attracts both hummingbirds and butterflies, and is also known as Hummingbird Bush, Wright’s Acanthus, and Mexican Flame.  It is the host plant for the Crimson Patch, Elada Checkerspot, and Texan Crescent butterflies. The fruit is a small, hood-shaped capsule with seeds attached to a hooked stalk that helps to eject them from the capsule when it dries and splits open.

Flame Acanthus

Flame Acanthus seed capsule

Crimson Patch

Violet Ruellia is an erect herb that is woody at the base with few branches, growing to 2 feet tall.  The dark green leaves are oval-shaped, and the trumpet-shaped violet flowers at the ends of stalks open at sunrise and fall from the plant in early afternoon, from March all the way through October. Also called Wild Petunia, it does well in sunny areas and is a host plant for the Common Buckeye butterfly.  One of its’ subspecies is a host plant for the Malachite butterfly, a south Texas species rarely seen in central Texas.

Violet Ruellia

Common Buckeye

Often stout and forming colonies 5 feet high, Western Ironweed has hairy unbranched stems, large green leaves with serrated edges, and loose clusters of bright purple blooms at the apex of each stem.  From July to the first frost, these fuzzy blooms provide nectar for various types of pollinating insects and the seeds nourish several species of birds.  Also called Baldwin’s Ironweed, it is the host plant for the Parthenice Tiger Moth.  While this species’ growth can be aggressive, it flourishes if allowed to spread in larger, open, sunny areas.

Western Ironweed

These native species can (and often should) be pruned back in winter as they can get too leggy.  They have low water needs once established, and can tolerate hot temperatures and still continue to bloom.  They are the perfect plants to beat the heat, benefit our local wildlife, and provide much needed color in your own native summer garden!

Leafy Treasures

Rusty Blackhaw Viburnum

Fall is the time when the quiet, green palette of summer gives way to the crisp reds, vibrant oranges, and mellow yellows that paint the natural landscape.  During the growing seasons of spring and summer, our trees and shrubs use sunlight to convert water and carbon dioxide from the air into sugar.  Called photosynthesis, this process begins to wane in November in Central Texas, and the leaves on some plants begin to change color in preparation for winter’s rest.

Mexican Buckeye

Pigments are natural substances formed by the cells of leaves that provide the basis for leaf color. Most familiar is chlorophyll, which produces the color green, and is vitally important as it is required for photosynthesis.  Carotenoid, which produces the colors yellow, orange, and brown, is a common pigment in many fruits and vegetables, as are anthocyanins, which produce the color red. Both chlorophyll and carotenoid are present at the same time in leaf cells, but the chlorophyll covers the carotenoid and hence the leaves appear green in the spring and summer.  Not all trees can make anthocyanins, however, and most are produced under certain conditions and only in the fall.

Flameleaf Sumac

As the days grow shorter, the decreasing amount of sunlight eventually causes trees to stop producing chlorophyll.  When this happens, the carotenoid in a leaf can finally show through, turning the leaves into a myriad of yellows, oranges, and browns.  Red, on the other hand, is an entirely different matter.  Affected by temperature and cloud cover, red fall colors can vary greatly from year to year.  A lively showing of reds depends upon warm, sunny autumn days and cool, but not cold autumn nights.  This type of weather pattern triggers the production of anthocyanins, which the tree produces as a form of protection.  Anthocyanins allow trees to recover any sugar or nutrients left in the leaves, moving them through the leaf veins and down into the branches and trunk, and its presence generates the red color before the leaves fall off.  Rainfall during the year can also affect fall color, with too much lowering the overall color intensity, and too little delaying the arrival of color.

Bald Cypress

Fall leaf color can easily be used to help identify local tree and shrub species.  The most notable reds and oranges in our area are produced by Texas Red Oak, Flameleaf Sumac, and Rusty Blackhaw Viburnum.  Dotting the hillsides, roadsides, and upper reaches of wooded canyons, they contrast well with the surrounding greens of Ashe Junipers and Live Oaks.  Golds and yellows are represented by Eastern Cottonwood, Escarpment Black Cherry, Mexican Buckeye, Bald Cypress, and Little Walnut, whose colors transform the low-lying areas near creeks and streams.   

Little Walnut

While a tree’s trunk and branches can survive the colder winter temperatures, many leaves cannot. Made up of cells filled with water and sap, these tissues are unable to live throughout the winter, and the tree must shed them to ensure its survival.  As the days grow shorter, the veins that carry sap to the rest of the tree eventually close.  A separation layer forms at the base of each leaf stem, and when complete, the leaf falls.  Some oak trees are the exception, with this layer never fully detaching and the dead leaves remain on the tree until new spring growth pushes them off to the ground.  Once on the ground, the leaves slowly decompose with the help of earthworms, beneficial bacteria, and fungi, creating the soil necessary for the continuation of the cycle of life.