Rocky mountain zinnia (Zinnia grandiflora) is a small subshrub that can grow to be 22 cm tall. Rocky mountain zinnia is native to the southwestern United States, the southern central United States, and Mexico. This species was traditionally used by the Zuni people in spiritual ceremonies.
I. Appearance and Characteristics
Zinnia grandiflora is a species of flowering plant in the family Asteraceae known by the common names Rocky Mountain zinnia and plains zinnia. It is native to the southwestern and south-central United States (Kansas, Oklahoma, Texas, Colorado, New Mexico, Arizona) and northern Mexico (Chihuahua, Coahuila, Sonora, Tamaulipas, Nuevo León, Zacatecas).
Zinnia grandiflora is a small flat-topped or rounded subshrub growing up to 22 cm (8+1⁄2 in) tall with many slender, branching stems. The oppositely arranged leaves are linear and 1–3 cm (1⁄2–1+1⁄4 in) long. The herbage is covered in short, rough hairs. The flower head has 3 to 6 bright yellow ray florets each between 1–2 cm (1⁄2–3⁄4 in) in length. At the center is a cluster of several tubular disc florets. It grows on plains and foothills and other dry habitats in the southwestern and south central states of the United States. It blooms from around April through November. Zinnia Grandiflora grows best in the sun and with more dry soil. This flower is good for drier landscapes because they are “drought-tolerant” meaning they do not need lots of water to grow. Zinnia Grandiflora can’t live in wet conditions. this plant works very well to help fight erosion due to its rhizomes. Rhizomes are stems that grow horizontally to the ground making them very sturdy which helps stop erosion. They are also good for pollinators because they do not have any insect issues and will attract insects good for a garden such as butterflies.
II. How to Grow and Care
Sunlight
Rocky mountain zinnia likes habitats with sufficient sunlight. It’s best to place it in full sun to grow, with no less than 6 hours of direct light. Rocky mountain zinnia will bloom with gorgeous flowers in such environments, and it also helps keep the leaves dry and prevent powdery mildew. If sunlight is insufficient, the plant is likely to spindle, weaken, and have less lush blooms.
Temperature
Rocky mountain zinnia is originally from Mexico. It likes hot weather and is sensitive to low temperatures. It pretty much needs reseeding every year. The best temperature range for it is 18 to 25 ℃. When winter temperatures drop below 13 ℃, it stops growing and its stems and leaves dry up and turn yellow. However, it can tolerate high temperatures above 30 ℃ and grow and bloom normally. Some heat-resistant varieties can even tolerate temperatures above 35 ℃. The temperature needs to stay above 15 ℃ for seedlings; temperatures below that negatively affect growth. Rocky mountain zinnia doesn’t require much water and is drought-tolerant.
Watering
Adapted to the arid conditions of its native habitat, rocky mountain zinnia thrives with minimal moisture and has a high drought tolerance. This species prefers infrequent watering, aligning with its adaptation to environments where water is a precious commodity. Consequently, it requires watering every week to maintain optimal health. In an outdoor setting, rocky mountain zinnia exhibits resilience in dry climates and benefits from the occasional rain, which satisfies its modest water needs without necessitating frequent human intervention.
Soil
The only soil requirement of rocky mountain zinnia is good drainage. Its roots don’t like moist soil. Too much water in the soil can cause powdery mildew. If possible, use soil with neutral pH value.
Fertilizing
For rocky mountain zinnia, apply a balanced nutrition fertilizer seasonally to promote robust growth and vibrant blooms. Use sparingly, as over-fertilization can harm rocky mountain zinnia’s root systems. During the growth phase, fertilize every 4-6 weeks, but ease off once flowering begins. Use a slow-release formula to ensure consistent nutrient delivery without overwhelming rocky mountain zinnia. Adjust schedules based on rocky mountain zinnia’s response and environmental factors, reducing frequency in dormant periods. Safety tip: Avoid contact with rocky mountain zinnia’s foliage when applying fertilizer to prevent burn.
Plating Instructions
Sowing is the simplest way to propagate rocky mountain zinnia. Indoor sowing can take place 4-6 weeks before the last frost every spring. Of course, direct sowing can also be performed outdoors, but it requires warmer soil temperature after the last frost. Rocky mountain zinnia seedlings are sold at almost every garden center, so you can purchase those directly and save yourself the trouble of sowing.
Pruning
Pinch rocky mountain zinnia seedlings back when they are young. Nip the buds on the branch tips to promote lush growth of the stems and leaves, so the plant grows into a shorter, more stocky, exuberant form. For taller varieties, support the plant with sticks to prevent it from growing obliquely or creeping on the ground.
Deadhead the spent flowers to reduce unnecessary nutrition consumption, so the rest of the flowers flourish and flower longer. To deadhead, cut below the flowers and above the leaves so that the plant continues to grow and sprout new flower buds.
Propagation
Rocky mountain zinnia is a perennial that thrives in well-drained soil with full sun exposure. For an effective propagation, ensure the cuttings are taken from healthy, non-flowering shoots. It’s crucial to prepare a potting mix that is light and allows good aeration. Cuttings should be dipped in rooting hormone and planted in the mix, with consistent moisture maintained without waterlogging. Root development can be facilitated by placing the pot in a warm, bright area without direct sunlight.
Transplanting
Ideal for transplanting rocky mountain zinnia is in the tender period of spring to early summer (S3-S5), as the moderate temperatures aid in root development. The perfect resting spot for rocky mountain zinnia features plenty of sun. Pro tip: Move at the first sign of over-crowding to encourage hearty blooms.
III. Uses and Benefits
Zinnia Grandiflora is used for many things from medicinal purposes to dyes and paint. They are also non-toxic to pets.
This plant is used by several Native American groups, including the Zuni and Navajo, for medicinal and ceremonial purposes.
Among the Zuni people, this plant is applied in a poultice to bruises, cold infusion of blossoms used as an eyewash, and smoke from powdered plant inhaled in sweatbath for fever.
The Acoma and Laguna Indians used Zinnia Grandiflora to heal kidney illnesses by drinking an infusion of it. It was also used on buckskins to dye them yellow. By adding the flower to water or white clay it can also be used to color wool. Scientists are also looking into other uses of Zinnia grandiflora as well.
IV. Harvesting and Storage
With proper care, rocky mountain zinnia flowers from summer through fall. Harvest the flowers when the temperature is low and humidity is high, generally in the morning. Harvesting in the cool of the day, when plants have the most moisture, helps the cut flowers last longer.
After the flower season, get rid of the withered plants and grow something else for a change. For rare rocky mountain zinnia varieties, consider keeping some withered flowers from one or two plants to harvest the seeds for sowing next year.
