Red ruellia (Ruellia elegans) is often used in pollinator gardens, as its scarlet flower show is loved by butterflies and hummingbirds. Since it’s so eye-catching and deer resistant, it’s also used in landscaping for beds, borders, and patio decoration. It’s technically an annual plant, but since it reseeds easily and spread quickly, some actually consider it a perennial.
I. Appearance and Characteristics
Ruellia elegans is a species of flowering plant in the family Acanthaceae. It is a subshrub native to eastern and southern Brazil, where it grows in the Cerrado ecoregion.
It is used as an ornamental plant, and it is pollinated by hummingbirds. Large scarlet-red blooms on & off from spring until first frost. Can take full sun with adequate moisture like in a tropical location but best in shade. Generally deer-resistant.
II. How to Grow and Care
Sunlight
Red ruellia prefers partial shade to full sun and differs in appearance depending on the light it gets. Full sun results in purple stems, while shading produces green stems. In areas with the harsh sun during summers, it may do better in some shade. Bright, filtered sunlight is best if the plant is grown under glass.
Temperature
Red ruellia favors warm, humid environments, as it originates from South and Central America as well as southern parts of North America. The coldest it can cope with is -9 ℃ for short periods. At the lower temperatures of the preferred range, it may grow slowly and produce fewer flowers. The same may be true at higher temperatures.
It prefers humid environments and consistently moist soil but can tolerate short periods of drought. Red ruellia likes being near sources of water such as riverbanks or the perimeter of boggy areas. Care should be taken when planting near these areas, as it can become invasive.
Watering
Originating from moist environments, red ruellia thrives in conditions that mimic its natural tropical habitat with consistent humidity. This species is adapted to regular hydration but can withstand brief periods of dryness. Its watering routine should align with a once every week schedule to maintain optimal growth. Typically grown outdoors due to its preference for warm climates, red ruellia benefits greatly from mulching which helps retain soil moisture and reduces the need for frequent watering.
Soil
Red ruellia can tolerate many different soil conditions. The preferred pH of the soil is 5.5-7.8. Soils that are fertile and organic and wet or boggy are favored. It is also able to grow well in average soil that has good drainage, providing it is kept consistently moist. Once established, it is resistant to short periods of drought. If grown in pot soil, it should have reasonable drainage, as diseases can occur if its roots are too wet for long periods.
Fertilizing
For red ruellia, a balanced approach using high-phosphorus fertilizer fortifies blooming. Administer quarterly during growth, reducing in cooler months. A teaspoon per gallon of soil suffices. Over-fertilization risks foliage at bloom’s expense. Seasonal adjustment enhances vigor, with lighter feeding in fall. Water before fertilizing to prevent root burn, ensuring optimal uptake and plant health.
Planting Instructions
Red ruellia is readily available in pots or as seed, which can be sown outdoors in spring. Spring is also the best time to plant red ruellia in the ground. It is not particularly fussy regarding soil type and copes with either good compost or native soil. When planting in the ground, choose a site with shade to partial shade.
Topsoil or peat moss can be added to the hole beneath the plant to improve soil structure and water availability to the roots. Water well after planting.
Red ruellia attracts butterflies and hummingbirds. It’s best to plant in the ground, as rapid growth can cause it to outgrow containers quickly. That said, containers are useful planting options to restrict the spread of this plant.
Another method to reduce spread is to plant it behind solid edging, or have a regular maintenance routine to pull up every unwanted plant. Planting near wetlands is not recommended, as it is likely to colonize the area very rapidly. Although sterility stops spread by seed, it remains aggressive in its spread of roots.
Pruning
Red ruellia does not require much pruning. Remove dead leaves and flowers after flowering for aesthetic purposes, and to stop it going to seed, which may result in spreading. Pinch young shoots to encourage branching and more flowers. Remove and dispose of the debris to avoid attracting unwanted bugs or animals. Damaged or unwanted branches can be pruned back to ground level in late winter or early spring.
Propagation
Belonging to the Acanthaceae family, red ruellia is a vibrant flowering perennial. It can be effectively propagated through stem cuttings. To ensure healthy root development, it’s essential to select a robust non-flowering shoot and cut just below a leaf node. The cutting should then be dipped into rooting hormone and placed in well-draining soil. Maintaining a humid environment is advantageous for root formation, so cover the cutting with a plastic bag or use a propagation chamber if available. Regular misting helps, but avoid water logging as it can cause rot. Gradual acclimatization to outdoor conditions is necessary once roots establish.
Transplanting
The ideal season to transplant red ruellia is between late winter and early spring (S2-S3) because it allows the plant to establish before warmer weather. Red ruellia prefers a sunny to partly shady location. Be gentle during transplant, to avoid damaging their fragile roots.