|By William J. Scheick
Professor, University of Texas at Austin
azzling flowers from Mexico provide some of the most striking features in Texas gardens. Several of these beautiful south-of-the-border plants were profiled a year ago in TEXAS GARDENER (September/October, 2003). On this occasion, we highlight five more prolific bloomers that will brighten yard or deck from summer through autumn.
For mid-summer garden color, Mexican sunflower (Tithonia rotundifolia) earns rave reviews. What this 4 to 6 foot annual lacks in overall symmetry is offset by copious daisies in shades of orange irresistible to butterflies and gardeners alike. Such cultivar names as ‘Aztec Sun,’ ‘Yellow Torch’ and ‘Sundance’ aptly describe their dramatic disk-and-ray flowers. ‘Fiesta Del Sol’ and “Goldfinger” offer compact, shorter selections.
Reported to be deer resistant, Tithonia requires only sufficient sunlight, regular watering when dry, good drainage and no slugs. Ideal for spacious, wind-protected garden backdrops throughout Texas, this slightly fragrant plant lasts until first frost. But Mexican sunflower amply reseeds itself even while flowering. In fact, under ideal conditions in southern parts of our state, it can sow a second round of plants during the summer.
Offering abundant yellow flowers during the hottest months, butterfly or orchid vine (Mascagnia macroptera) similarly requires little maintenance. This Mexican native will climb supports to an impressive 15 feet or simply self-twine to form attractive cascading mounds. As early as late summer, while blooming is still underway, butterfly vine produces viable seed in dry winged-fruits. Each fruit splits into three sections looking like a yellow-green butterfly.
Deciduous or evergreen, depending on local conditions in zones 8 and 9, this frost-tender perennial is moderately drought tolerant once it is established in compost-rich and well-draining soil. During its first year, some experimentation with irrigation is recommended. While over-watering is harmful, regular hydration in fully exposed locations during dry spells maintains the landscape appeal of this vigorous plant. Protective winter mulching in zone 7 should ensure butterfly-vine’s return in the spring.
The exquisitely shaped flowers of yellow alder (Turnera ulmifolia) seem to glow from dark-green niches. Often sold as buttercup or sage rose, this Brazil-to-Mexico shrub attracts various butterflies, including the orange Mexican Fritillary when visiting south Texas. New flowers appear daily, and viable seed is produced under optimal conditions.
This 2-to-3 foot mounding perennial shares the same temperature range as butterfly vine, and horticultural experiments have shown that it successfully withstands Texas summers. However, when temperatures exceed 85 degrees Fahrenheit, this long-blooming tropical benefits from afternoon shade where its usual morning-only flowers tend to remain open longer. Because of its sensitivity to freezes, yellow alder is often treated as an annual ideal for containers. It also thrives in garden borders which are well-drained, slightly acidic, somewhat composted, adequately watered, and occasionally fertilized.
Firecracker plant (Russelia equisetiformis), another continuously blooming hummingbird magnet, produces spikes which start out erect but eventually form 3 to 4 foot arched sprays of suspended scarlet bells. Fountain bush, as this Mexican tropical is also called, cascades beautifully over the edges of a container, especially when suspended. As a salt-tolerant, freeze-tender perennial, it makes a fine choice for coastal Texas gardens with good drainage.
Although technically zeriscapic, fountain bush is less heat-tolerant than butterfly vine. During the summer it will shed leaves unless, like yellow alder, it receives afternoon shade. Adequate sunlight, fertilization, compost and hydration (only when dry) are essential for this fast-grower, which propagates so easily by weeping shoots that it will likely self-spread beyond its original bedding.
MEXICAN FLAME VINE
For sheer beauty, the brilliant orange daisy clusters of Mexican flame vine (Senecio confusus) are hard to beat. This trouble-free climber with arrowhead leaves rapidly blankets a chain-link fence or a column. It offers a continuous spring-to-fall procession of blooms which slowly turn red as they age. This sun-loving perennial, also available as a ‘Sao Paulo’ cultivar with only red flowers, especially appeals to Gulf Fritillary butterflies.
Once established, flame vine is not a fussy plant. It thrives in most draining soils, is pest-free and tolerates short-term droughts. To ensure ongoing flowering, however, regular watering is necessary during dry spells. If protectively mulched during zone 8 winters, this tropical climber will reappear in the spring.
Like firecracker plant, flame vine spreads by rooting wherever its branches touch the ground. So invasiveness may be an issue, although occasionally clipping runners is a small price to pay for such a glorious show of sun-radiant flowers.
For Butterfly Vine, Firecracker Plant and Mexican Flame Vine
1028 East 1st Street
DeRidder, LA 70634
For Yellow Asher
P.O. Box 298
401 Terra Ceia Road
Terra Ceia, FL 34250
For Mexican Sunflower
P.O. Box 460
Mineral, VA 23117