Plectranthus Mona Lavender is an ornamental plant with vibrant foliage and striking blooms. Developed in South Africa, this hybrid enhances gardens and indoor spaces. Its ease of care makes it appealing, and its common name reflects its lavender flowers.
Characteristics and Origin
Developed at Kirstenbosch Botanical Garden in South Africa in the 1990s, Plectranthus Mona Lavender is a hybrid of Plectranthus saccatus and Plectranthus hilliardiae ssp. australe ‘Magwa’. This perennial shrub grows 1 to 2 feet tall and wide, forming a dense, rounded shape. Its dark green, ovate leaves have toothed edges and a contrasting rich purple underside.
Tall spikes of tubular, two-lipped lavender flowers, often purple-spotted, emerge above the foliage. Blooms appear from late summer into winter, or through spring in mild climates. As a “short-day plant,” its flowering is triggered by shorter daylight hours, adding color when other plants are dormant.
Essential Care Requirements
Light
Plectranthus Mona Lavender thrives in bright, indirect light and tolerates partial shade. Outdoors, filtered sunlight or morning sun is suitable, as intense afternoon sun causes leaf burn. Indoors, a south or east-facing window providing bright indirect light is ideal. Light intensity influences foliage and flower color, with brighter light resulting in richer hues.
Watering
It requires consistent moisture. Water when the top inch of soil feels dry, which may be every few days depending on conditions. Water thoroughly until it drains from the pot, avoiding standing water to prevent root rot. Room-temperature or slightly warmer water is recommended, as cold water can shock the plant.
Soil
Plectranthus Mona Lavender prefers rich, well-draining soil that is slightly acidic (pH 5.6-6.5). A potting mix rich in organic matter, like peat-based blends with perlite or vermiculite, provides drainage and aeration. While tolerant of average soil conditions, optimal growth occurs in a medium that retains moisture but avoids waterlogging.
Temperature and Humidity
Optimal temperatures for Plectranthus Mona Lavender range from 60-80°F (15-27°C) year-round. While it can withstand light frosts down to 25-30°F (-4 to -1°C), prolonged exposure to temperatures below 50°F (10°C) can cause damage. It enjoys moderate humidity, similar to its native subtropical environment. In dry indoor environments, especially during winter, increasing humidity with pebble trays or humidifiers can help.
Fertilizing
During the active growing season, fertilize Plectranthus Mona Lavender every 2-10 weeks with a balanced, water-soluble fertilizer. Balanced fertilizers (e.g., 10-10-10) provide nutrients for healthy growth and blooming. During the plant’s flowering period in fall and winter, withhold fertilizer, resume when blooming tapers off. Excessive nitrogen can promote foliage growth at the expense of flowers.
Pruning and Shaping
Pruning helps Plectranthus Mona Lavender maintain shape, encourage bushier growth, and promote blooming. Regularly pinching back the tips of young plants encourages branching and a compact form. This involves removing stem tips, signaling the plant to produce new growth from side shoots.
Deadheading (removing spent flowers) also encourages blooming by preventing energy expenditure on seed production. After flowering, trimming off flower spikes directs energy towards vegetative growth and reblooming. If the plant becomes leggy or overgrown, it can be pruned back to rejuvenate its form.
Propagation Techniques
Propagating Plectranthus Mona Lavender is achieved through stem cuttings, similar to other mint family plants. To take a cutting, select a healthy stem and cut a 4- to 6-inch section just below a leaf node. Remove flowers or buds, and strip leaves from the bottom third to half.
Cuttings can be rooted in water or a porous potting mix. If rooting in water, suspend the cutting in a jar of clean water in bright, indirect light; change water regularly to keep it fresh. If planting in soil, use a moist, well-draining potting mix and insert the cutting 1-2 inches deep. Roots typically form within a few weeks, allowing transplant.
Overwintering and Common Issues
Overwintering
In USDA hardiness zones 10 and 11, Plectranthus Mona Lavender can be grown outdoors year-round as a perennial. In cooler climates with freezing temperatures, bring outdoor potted plants indoors for frost protection. Alternatively, gardeners can take cuttings in the fall to propagate new plants indoors for the winter, ensuring a supply for spring. When overwintering indoors, provide bright, indirect light and maintain a warm environment.
Common Issues
Plectranthus Mona Lavender is robust when grown outdoors in suitable conditions. However, issues can arise, particularly indoors or under suboptimal care. Common pests include whiteflies, aphids, and spider mites, managed with horticultural oils or insecticidal soaps if severe. Adequate humidity can deter spider mites.
Root rot can occur from overwatering or poorly draining soil, leading to leaf drop. To address this, allow soil to dry between waterings and ensure pots have sufficient drainage holes. Leggy growth, characterized by long, sparse stems, often indicates insufficient light, especially indoors during winter. Providing brighter indoor locations or hard pruning can encourage bushier growth.