Discovered in Java in the 1800s Coleus have a somewhat mysterious origin, although it’s generally agreed they originated in south-east asia.
Made popular as Victorian-era bedding plants, they’ve made a huge comeback in recent years thanks to the all-season color in full sun or part shade.
In really hot places, partial or light shade is best in summer. They love full winter sun in Central Queensland, in summer they’ll need much more frequent drinks.
Planted outdoors in early spring, they quickly grow to their full size in a single season. Large swaths of assorted coleus plantings that take on a quilt-like appearance can look luscious in a landscape or garden beds. You can also grow ’em for colour in window boxes, outdoor container gardens, and hanging baskets.
However, coleus plants are not at all frost-tolerant, so don’t rush to get your plants in the ground. Wait until temperatures remain reliably above 15 degrees Celsius before you move them out in the garden. They will do best in rich, loose soil, so amending with compost or peat moss before planting is advised unless you have very good soil.
In colder climates, if you want to overwinter them, they must either be dug up, potted, and brought indoors for overwintering or grown through cuttings to establish additional plants. Otherwise, treat them as tender annuals and enjoy them while they flourish.
Warning: Some species of Coleus plants contain mildly toxic elements, including a compound called diterpene coleonol. The toxins don’t pose a major health risk to people. The most common effects include mild or minor skin irritation from exposure to skin or from ingestion of Coleus sap.
The same toxins are more of a threat to animals, including dogs, cats, and horses. Coleus poisoning can lead to vomiting, diarrhea, lethargy, loss of appetite, difficulty breathing and if enough is consumed, may become fatal.