Coleus Basics

"The best thing about putting them in the sun is that the colors are much more intense and vivid," he says. "If you leave them in the shade, they'll get dull."

From large to tiny leaves with delicate to bold leaf edges in a variety of in-your-face colors, it's easy to see why this summer annual is coveted for its foliage. The flowers pale in comparison and are generally cut off to promote plant growth elsewhere. You don't want these plants expending energy for flower production.

Trimming coleus makes for bushier, sturdier plants. Sometimes a coleus gets a little too tall or grows unevenly, so cutting it back gives it a more uniform shape. Save the cuttings for making new coleus.

Propagating coleus

Coleus can be started from seed, cuttings, transplants or potted plants purchased from the nursery. Just give them the basics and watch them take root. "This is a plant that just wants to grow. Provide it with enough light, decent soil and enough water, and it's going to grow quickly," says Silk.

To grow your own from cuttings, first prepare the soil mixture. Silk likes to use one part perlite combined with one part potting soil. As he mixes, he adds enough water to make the soil as moist as a lightly squeezed sponge. "It often takes more water than you think because the perlite absorbs more moisture," he says.

Once the soil mix is ready, fill pots with the mix and make two-inch-deep holes for each cutting, using a pencil or your finger. Before planting, the cutting needs preparation. Remove any flowers by cutting back to a pair of leaves. This will force the plant's energy into making roots.

Silk recommends keeping three sets of leaves. After the fourth set, he cuts the stem and removes the bottom leaves. "Where I cut the branches off at the bottom is where the first new roots are going to form," he says. Then stick the wound of the cutting into the rooting hormone, a product that kickstarts root growth. Lightly tap off the excess hormone from the cutting and stick it into the hole, firming the soil around it.

Place the pots with cuttings on a tray and water the tray, instead of the plants, so you don't wash away the rooting hormone. Then place the tray in the shade, keep it watered and wait for roots to form. After a couple weeks or so, check the bottom of the pot. When roots start coming out of the bottom of the pot, the coleus is ready to plant in the garden.

Planting coleus

Container gardening with coleus

If you don't have a lot of room to grow coleus in your garden, use them in containers. Pair different selections together or with complementary plants. Silk recommends fertilizing with liquid 20-20-20 about once a week.

While new cultivars are able to handle the heat, once the temperatures begin to drop below 50 degrees F, coleus will not be a happy camper. They're considered annuals because even the slightest hint of frost causes damage to the plant. Overwintering indoors on a sunny windowsill is one solution, but does have drawbacks.

If you bring coleus indoors for the winter, don't worry if it begins dropping leaves. That's the plant's way of adjusting to less light and cooler temperatures.