The Mona Lavender plants are slowly becoming a favorite indoor plant for many plant lovers and for a good reason. When most other plants enter dormancy, this beauty sends flower spikes with tubular lavender flowers. The fascinating thing is that the shorter daylight hours trigger the bloom period. So you can enjoy a flower color right through winter to early spring.
I. Appearance and Characteristics
Plectranthus is the largest South African genus of plants belonging to the mint family (Lamiaceae). There are many Plectranthus species (around 44) that are currently used as ornamental herbaceous plants throughout the world’s gardens. They come in a number of shapes and colors ranging from white, pink to dark mauves and lavenders. Being so easy to propagate from cuttings, they are readily shared amongst keen gardeners and are one of the plants that grow well in shade.
“Mona Lavender” was bred at the Kirstenbosch Botanical Gardens in Cape Town, South Africa in the late 1990s. It was a fairly long process involving much hand pollination and raising many thousands of seedlings, back crossing and raising many more thousands of seedlings- each time selecting out the best, most attractive individuals to go through to the next round of breeding. Recently, the “Mona Lavender” plant has become a hit around the world!
“Mona Lavender” is a quick-growing perennial shrub, reaching 18 to 24 inches tall. It does very well in either shaded or partly sunny positions. When it receives sun it tends to stay smaller and more compact, and the leaves exhibit a much more intense coloring, especially on the purple undersides of the leaf. The foliage is unique and special, but the real prize on this plant is the dark lavender flower spikes. These flowers appear in early spring and continue to add color to your garden until the first frost.
II. How to Grow and Care
Sunlight
The trouble-free plant prefers partly sunny positions in the garden with some morning sun. Still, it thrives in partial shade in the afternoon and grows in warmer climates. It can tolerate full shade but will affect the foliage and bloom colors.
So keen gardeners prefer growing the perennials with some afternoon shade with bright light in the morning sun for richer colors. As houseplants, these plants enjoy standing in bright indirect light.
Temperature and Humidity
The Mona thrives in year-round temperatures between 60°F to 80°F. Nonetheless, the plant can withstand only light frosts with temperatures down to 25°F. When grown in warm climates, flowering occurs in the fall and winter.
Your Mona will need added water during the bloom time. Also, withhold fertilizing as it will boost new stem tips, not flowers. The same applies to indoor plants if you want them to flower well.
You can expect your Mona to flower consistently from late summer to spring for garden plants in mild winter temperatures. Yet, a warning is that your Mona is very sensitive to freezes. So, bringing your plant indoors or taking some cuttings to propagate and grow your Mona annually for freezing climates.
Watering
‘Mona Lavender’ will grow best when provided with both regular and even moisture. It’s considered a thirsty plant and should be watered every few days, whenever the top inch or soil feels dry to the touch. However, make sure the soil drains well to avoid root rot.
Soil
When choosing soil, opt for a well-drained, slightly-acidic (pH 5.6-6.5) variety containing organic matter. Choose rich, loamy soil that drains well.
Fertilizing
‘Mona Lavender’ can be fertilized every six to ten weeks with a balanced water-soluble fertilizer. For the amount to use, follow the product label instructions. In alkaline soils, fertilizing with an acidifying fertilizer can help improve both foliage color and flowering. During the short days when ‘Mona Lavender’ is flowering, it is best to withhold fertilizer, resuming when the flowering begins to taper off.
Planting Instructions
Pruning
Though this plant doesn’t require a significant amount of pruning, you can pinch young plants regularly to help encourage branching and the fuller, bushier growth. Long-growing stems can also be snipped (if you wish, these can be rooted to propagate new plants).
Trim off new stem tips on a regular basis to help the plant retain its compact shape and form, and remove the flower spikes after blooming.
Propagation
Cuttings
The easiest method for propagating new plants is to take stem cuttings and root them. The process is much the same as for Coleus, which are easily rooted either in a porous rooting mix or simply by suspending the cutting in water until roots form. Propagation can be done almost any time, but it is often done in the fall as a method for continuing plants that are being grown outdoors. By taking cuttings in fall, rooting them indoors and potting them up in the winter, you will have healthy adult plants ready to return to the patio or garden when spring arrives. Here’s an easy method to do it:
- Take 4- to 6-inch cuttings from the tips of healthy plants. Pinch off any flowers or flower buds, and strip the leaves off the bottom one-third of the stem.
- Suspend the cutting in a jar of clean water and place in a location with bright indirect light (the cutting can also be immediately planted in a porous potting mix, if you prefer).
- Watch the cutting carefully, adding water as it evaporates from the jar, and replacing it if it becomes yellow or brownish.
- When a good network of roots has developed, plant the cutting in a container filled with commercial potting mix, and continue to grow the plant in bright, indirect light.
- If the new plant gets excessively leggy, pinch off the stems to force bushier growth. In the spring when all danger of frost has passed, the new plant can be moved outdoors or planted in the garden. Make sure to harden it off first by giving the plant increasingly longer visits to outdoor conditions over a week or two.
Seed
Because ‘Mona Lavender’ is so easily propagated from stem cuttings, as well as the fact that ‘Mona Lavender’ is a hybrid cultivar, seed propagation isn’t done very often. Seed collected from the plant will not grow true to the parent, as it’s a hybrid variety. However, you can purchase ‘Mona Lavender’ seed from a reputable company if you have trouble finding live plants at local nurseries.
Sow the seeds indoors about six to eight weeks before the last spring frost, in seedling flats or small pots filled with a seed-starter potting mix. Sow the seeds shallowly, just barely covering them with mix. Place the flats or pots in a bright location (but out of direct sunlight) at a temperature of 70 to 75 degrees Fahrenheit. Seedlings usually emerge in seven to 14 days.
When the seedlings emerge, move them into direct sunlight or place them under fluorescent plant lights, giving them eight hours of darkness each night. When the seedlings are three to four weeks old and have at least two sets of true leaves, feed them with a half-strength solution of houseplant fertilizer.
Before planting outdoors, harden off the seedlings for a week. Make sure to move the seedlings indoors if freezing temps are expected. This hardening-off process toughens the plant cells and minimizes transplant shock.
Pests and Diseases
Common Pests & Plant Diseases
Like other Plectranthus species, ‘Mona Lavender’ is largely free of pest and disease problems when planted outdoors, provided they are growing in good, well-draining soil. Occasional pests can include whiteflies, aphids, and spider mites during the summer months. Horticultural oils can handle these pests if they become serious, but natural predators often take care of them without any intervention. Pests are sometimes more troublesome when ‘Mona Lavender’ is grown indoors as a houseplant.
Diseases include leaf spot, stem rot, and root rot, all of which are more likely in humid conditions or when the plants are growing in dense, poorly draining soils.
Common Problems
Other than the common pests that affect many indoor houseplants, ‘Mona Lavender’ is largely problem-free. But it can tend to get leggy and sparse, especially in indoor locations where it is not getting enough bright indirect light. This is a common problem in northern climates where daylight hours are short in winter. This can be remedied by hard pruning back of leggy stems, and by giving plants the brightest indoor locations you can find—usually a south- or east-facing window.
When you notice leaf-curling, this is always a sign that the plants are in need of water. These plants love moisture, but also need good drainage to prevent root rot.
Potting and Repotting
When growing Plectranthus in containers, be sure to choose a soilless medium designed for use in pots. Any pot material will work but make sure the pot is well-draining. When grown indoors, ‘Mona Lavender’ will do best in a spot near either a bright east or south window. When temperatures rise above freezing in the late spring, you can shift your plant outside for the summer. Do your best to protect ‘Mona Lavender’ from the afternoon sun, as this is a plant that cannot thrive in extreme heat.
Every year or two, repot ‘your ‘Mona Lavender’ plant into a larger container (1 to 2 times wider than the current one) using a well-drained potting mix. Or, you can propagate a stem cutting and discard the parent plant.
Overwintering
‘Mona Lavender’ plants being grown in the garden in warm climates usually enter their bloom period in the fall and winter, and will require extra water during this time. Fertilizer should be withheld, as it stimulates foliage growth at the expense of flowering. The same holds true for plants being grown indoors if you want them to bloom robustly.
‘Mona Lavender’ is very sensitive to freezes, so if you live in an area with freezing temperatures it’s essential that you bring outdoor potted plants indoors—or take cuttings to propagate indoors—if you want your ‘Mona Lavender’ plants to survive the winter.
III. Uses and Benefits
With its fall-through-winter bloom period, Plectranthus is normally grown as an indoor houseplant or potted patio plant, except in regions with very mild winters, where it takes on the role of a shrubby, broadleaf evergreen plant that flowers through the winter.
