You may have acquired a collection of stunning tender perennials that have added so much to your containers and gardens, but soon, frost will be imminent. Before you drag dozens (hundreds?) of pots indoors, first consider how much storage room your home/garage/cellar offers, (let’s assume you don’t have a greenhouse, but if you do, terrific!). Usually space is quite limited, and you’ll need to be ruthless in deciding what gets saved. Focus on the hard to find varieties. Next, decide what needs to be actively growing, and what can be stored as dormant roots (more on that in later blog postings). In general, plants that are the least cold tolerant (zones 9, 10 and 11), i.e. Coleus, need to be kept in an active state and need warm indoor temperatures.
We found that taking cuttings of easy to root plants like Coleus, Salvia and Cuphea is one way to limit the number of big bushy plants that will compete for light on your windowsill. Begin taking cuttings at the beginning of September and be sure to label each variety. Select non flowering tips with 2-3 nodes and remove the lower leaves. Dip the tips in a light rooting hormone and stick in a tray or pot of a light potting medium or sand. Place in a shady warm spot and water/mist several times a day for the next 2 weeks or so. A gentle tug will let you know when roots have taken hold. Once decent roots are set, gently unearth and transplant into small pots, or leave in the rooting pot itself. Go light on the fertilizing this fall and winter, since you do not want to encourage too much growth. In the spring, transplant into a richer soil mix. You can begin taking more cuttings as soon as vigorous fresh growth permits.