If you've spent any time wandering public gardens (or even those in your neighborhood), you've probably spotted coleus plants. A tropical perennial (typically grown as an annual) native to Malaysia and other parts of Asia, there are about 60 different species of coleus. The plant first gained popularity during the Victorian ages, but love for this easy, practically maintenance-free varietal has only grown since. Their beautiful foliage matures in about six months and can be found in a variety of colors, like green, purple, orange, red, and yellow, making it an ideal way to add visual interest to your garden.
While coleus can be planted successfully in the ground in early spring, it's actually easier to grow in containers, as it thrives in the loose texture of good potting soil. Container gardening with coleus is not difficult, but it requires a bit of preparation—it's slightly different than traditional outdoor gardening, mostly due to different maintenance requirements. Coleus can be grown in containers both indoors and outdoors, where pots of coleus work well to decorate a deck, patio, or window box.
|Botanical name||Plectranthus scutellarioides|
|Plant type||Herbacious perennial|
|Mature size||6 in.–3 ft. tall, 6 in.–3 ft. wide|
|Sun exposure||Partial shade, full shade|
|Soil pH||Neutral to acidic|
|Flower color||Blue, white|
|Hardiness zones||10, 11 (USDA)|
Coleus Plant Care
Coleus' needs when it comes to care are pretty minimal, making it a great introductory plant for novice gardeners or those who just don't have a lot of time on their hands to tend to their plants. Still, there are a few care tips you'll want to keep in mind to help your coleus plant thrive in a container. First thing's first: Make sure your pot is large enough to comfortably accommodate the mature size of the coleus. Choose something that the plant can "grow into"—coleus is fast-growing, and you don't want to have to be replanting it constantly when it outgrows its container. From there, maintain moist soil conditions consistently and keep the plant out of the sun.
Generally speaking, coleus is a full shade plant—while recent cultivars have made it more tolerant of sunlight, it still does not like direct, sustained sunlight and needs either shade or partial shade in order to thrive. If you notice the colors of your coleus plant look washed-out and dull, that's a good indicator that it might be getting too much sun. Likewise, if your plant starts to lose leaves, it usually means that it's in a spot that's either too dark or too cold.
When it comes to growing coleus in containers indoors, a lack of light is usually not a problem. However, during cold winter months, coleus plants grown indoors may have trouble getting just enough light. To help, place your pots somewhere where they'll receive filtered sunlight through windows, or provide them with supplemental lighting.
One of the reasons that coleus plants grow so well in containers is because they prefer the loose texture of potting soil versus more dense ground soil. When potting, use a high-quality mix, and make sure that your pot has good drainage to help prevent root rot (soil that is too heavy or dense can also cause the roots to rot). Additionally, coleus plants thrive best in soil that is neutral to acidic, specifically with a pH level between 6 and 7.
Coleus plants are not very drought tolerant, so it's important to develop a good watering cadence that allows you to keep your coleus well-hydrated but not soggy. In hot months, coleus plants grown in pots outdoors will need watering once or twice a day. If grown indoors, watering every two or three days is usually sufficient unless the air inside your home or grow space is especially dry. If you pot in a porous material like terracotta or clay, consider lining them with plastic to keep the soil moist.
Temperature and Humidity
As a tropical plant, coleus loves warm weather. It does not tolerate cold weather or cold soil well, so keep your plant indoors until temperatures reach at least 70 degrees Fahrenheit. If you notice the leaves of your coleus blackening, chances are it's beginning to die because of cold temperatures and you should take it inside. Indoors, keep your coleus plant in a warm room with ambient sunlight, away from any harsh breezes (like in front of an air conditioner). If your space tends to have dry air in the winter months, a humidifier can go a long way in keeping your tropic-loving coleus happy.
Like many plants with colorful foliage, coleus plants need regular feeding. To keep your coleus thriving, mix a slow-release fertilizer into the potting soil when you are starting your plant's container. Then, feed it a diluted liquid fertilizer every week or two as it continues to grow. Because the plant needs frequent watering, any nutrients you provide it with are typically washed away quickly and it will need more frequent feeding than it would in a garden bed.
Is Coleus Plant Toxic?
While not all varietals of the coleus plant are toxic to animals, a few do possess a toxic compound called diterpene coleonol, found in the oils and sap of the plant. As a general rule of thumb, it's a good idea to keep all coleus plants out of reach of pets. If ingested, call your vet immediately.
Symptoms of Poisoning
Symptoms of poisoning in pets include vomiting, diarrhea, bloody stool, lethargy, weakness, difficulty breathing, and loss of appetite.
Without regular pruning, coleus plants can become "leggy" and unattractive. If you prune and cut them back faithfully, your coleus should stay bushy and full. Shear the tops of plants that grow too tall to encourage outward growth and denser foliage. Excessive legginess is typically caused by too little sun, so if this is a continuing problem, move the container to a spot that receives a little more sunlight. A coleus plant grown indoors, especially in winter months, is more susceptible to this, so you might need to supply your plants with some supplemental light.
To propagate your coleus, cut several sprigs from your favorite mature plant (each sprig should contain several good, healthy leaves). Place each cutting into a clear glass vase or jar filled with water, making sure to pluck off any leaves that fall below the water level. Place the vases in a bright, warm area and allow the cuttings to root themselves—roots will generally appear within a few days, and over a period of a month or two will develop into a thick mass of roots. Keep the vases filled with water as it evaporates and is consumed by the plants' roots. If the water grows cloudy or brownish, replace it with fresh, room-temperature water.
As soon as the roots have formed a tangled mass, they can safely be planted in potting soil. Immature potted coleus plants will need plenty of light, either from a south-facing window or from supplementary lighting. An important note: some varieties of coleus root more easily than others. More exotic varieties with large, unusual leaves can be a bit temperamental about rooting, so it's a good idea to take plenty of cuttings in case some fail to root. Smaller, more traditional types of coleus root themselves very easily.