I added some coleus plants to my garden this year and would like to use them again next year. Can I bring them inside over winter for next year?
— Rachel Block, Morton Grove
It is easy to overwinter coleus plants inside at home, and this is the time to take cutting of your coleus plants if you want to overwinter them.
There are many different types of coleus, providing a wide range of foliage color. I primarily use them in containers, but coleuses will also work well as bedding plants or to drift into a perennial border.
Mid to late September is generally a good time to take the cuttings, depending on the weather, so it will be best to make the cuttings soon. If we have a warm fall, you may be able to wait a bit later. Coleuses are very sensitive to frost so even a light frost can do a lot of damage and prevent you from taking any cuttings.
Start by making about a four-inch cutting from the tip of a stem. Try to use stems that do not have flowers, but if no stems are available without flowers, then prune them off. Place the cuttings in water after stripping the lower couple of leaves that will be under water. Within a couple of weeks, you should see roots forming.
Once the roots have developed to around two inches in length, pot up the cuttings using a high-quality growing medium for containers. I have had good success using four-to-five-inch clay pots for the cuttings. You can grow on the newly rooted cuttings outside until temperatures drop below 50 degrees. Then move the plants to a bright window inside for the winter.
Rotate the pots every two to three weeks for more even exposure to sunlight. The growth of the plants may become thin and stretched due indoor growing conditions. Pinch the plants back as needed, though your plants may get through the indoor winter season just fine. Most quality growing media will have a fertilizer so you should not have to fertilize the rooted cuttings over winter. Keep them on the dry side for watering to reduce chances of the plants rotting. Pots of coleus placed on a basement windowsill that is south facing perform well for me over winter.
For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at [email protected]. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.