Common Names: Mexican zinnia, narrow-leaved zinnia, orange zinnia
Mexican zinnia is an upright, bushy annual that is similar to common zinnia (Z. elegans). However, the leaves are smaller, only 2-3 in (5.1-7.6 cm) long. They are also narrower (almost linear) unlike the lance-shaped, 3-5 in (7.6-12.7 cm) long leaves of common zinnia. Mexican zinnia gets about 2 ft (0.6 m) tall with a spread of about 1 ft (0.3 m). The wild form has bright orange ray flowers on heads about 1.5 in (3.8 cm) across. Like the better known zinnia, Mexican zinnia has many cultivars to brighten up summer flower beds. ‘Old Mexico’ is a tried and true old-timer with a bushy habit and flowerheads in yellow, red and mahogany. ‘Chippendale’ has ray flowers that are bright red with yellow tips. ‘Star White’ has white rays and golden yellow discs. ‘Persian Carpet’ is dwarf, to 14 in (35.6 cm) tall, with double flowerheads in a wide combination of bi-colors including gold, maroon, purple, brown, cream and pink. ‘Orange Star’ is only 10 in (25.4 cm) tall and bushy with orange flowerheads; it makes a good annual groundcover.
Mexican zinnia is native to Mexico.
Light: Full sun.
Moisture: Mexican zinnia is quite tolerant of heat and drought. The ‘Persian Carpet’ series cultivars are perhaps the most drought and heat tolerant.
Hardiness: Mexican zinnia is a warm season annual that is very tolerant of long, hot summers. It cannot tolerate frost.
Propagation: Sow seeds where the plants are to be grown in spring after the last frost, or set out 6-8 week-old seedlings. Zinnias are sensitive to root disturbance, so be especially careful when transplanting.
Zinnias are traditional in annual flower beds and borders. Use the dwarf varieties in containers and window planters. Some of the short, bushy cultivars make nice summer groundcovers. Grow the taller varieties in borders and beds and for cut flowers. Pinch young stems back to encourage branching unless growing for long-stemmed cut flowers. Deadhead spent flowers frequently to prolong flowering. Zinnias will produce larger (but fewer) flowers if you remove side shoots.
Zinnias are among the few bedding plants that will continue to perform throughout long, hot southern summers, all the way up to the first frost. Mexican zinnia is even more tolerant of heat, dry weather and winds than is the common zinnia.
The name, Zinnia angustifolia has been misapplied to Z. haageana in the horticultural trade, but the former is in fact a distinct species from Central America that is smaller, to 15 in (38.1 cm) high, and has smaller narrower leaves to 2 in (5.1 cm) long. Narrow-leaved zinnia, as it is called, has ray flowers that are orange with a yellow stripe down the middle.