I brought in some coleus last fall per your suggestion and am finding the new growth has lost a lot of the vibrant color it had in the garden last year. Is there something I need to do differently to ensure that I have a good display this summer?
— Jennifer Chou, Morton Grove
It is not unusual for a coleus to be struggling at this point in winter while growing inside in a typical home setting. The light levels in a home are much lower than what the plant needs to grow well, so spindly growth and less vibrant colors are to be expected and should not be considered a problem. The lower leaves may have also fallen off your plants. If any stems are turning black and rotting, you may lose that plant. This is also an indication of overwatering. You can still count on having a good, colorful display in summer if your plants have lost some leaf coloration and display some spindly growth. I took a photo of the plants I am holding in a south-facing window. It took them several weeks to show any significant growth after being aggressively cut back before I brought them inside last fall.
I have been running my coleus dry by allowing the medium to dry out between watering. It’s best to water before you start seeing wilting of the leaves, although I have allowed this to happen several times already with no apparent ill effect. There is no need to fertilize your plants over winter. Go ahead and pinch any spindly growth back some to encourage a bushier plant. Rotate the pots every two to three weeks for more even exposure to sunlight and more upright growth.
You can also propagate more coleus for your garden this winter. Once there is enough new growth, use a sharp, clean knife or a pair of pruners to cut the stem just below a leaf node. Make about a 4-inch cutting from the tip of a stem — though a shorter one can also work if new growth is limited. Try to use stems that do not have flowers, but if no stems are available without flowers, prune them off. Place the cuttings in water after stripping off the lower couple of leaves that will be under water. Within a couple of weeks, you should see roots forming. Transplant to a pot with growing medium once a small mass of roots has developed to around 2 inches in length. Pot up the cuttings using a high-quality growing medium for containers. I have had success using 4- to 5-inch clay pots for the rooted cuttings.
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.
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