Now is the time to take action to save some of your favorite tender plants from cold winter weather. If looking to save a little money on plants next spring or you have a plant that is special to you, keep it for next year. Bring your plants indoors before the cold weather returns by following a few easy tips.
Tender perennials, usually considered annual plants in colder regions, are easily overwintered indoors. Care for them as you would any houseplant. Examples of perennial plants possibly growing in your garden are geranium, coleus, lantana, begonia, Persian shield and Joseph’s coat.
Plants can be overwintered indoors either by digging up the entire plant or propagating the original plant. Regardless of method, it must be done before the threat of first frost.
If the plant is small enough, or you have ample room, the entire plant can be dug up and planted in a container of fresh potting soil. Be sure to get as much of the root system as possible to cause it less stress. Cut it back so two-thirds to half of the original plant is remaining. This will allow it to focus on repairing roots rather than sustaining top growth.
Some plants can be easily propagated, a simple process to get new plants from existing plants. Tip cuttings are taken by selecting a healthy, 3- to 5-inch shoot with four to six leaves. Cut directly below a leaf node, or where the leaf is attached to the stem. Remove any flowers or buds and the bottom two to four leaves. Insert the lower portion of the cutting into a container of moist potting soil. Take several cuttings to ensure the survival of a viable plant. Cover the entire container with clear plastic to keep a high moisture level in the air while the plant is forming roots. Place the container in bright, indirect light. The plastic cover should be removed in three to four weeks after roots have developed.
Steps for overwintering plants:
- Inspect each plant carefully for signs of pests and diseases. Only bring healthy plants indoors. Rinse off leaves with water to remove any tiny insects that may be hiding. A treatment of insecticidal soap can also be applied as a precautionary measure before bringing inside.
- Dig up the entire plant, making sure to get all the roots you can, and replant it in fresh potting soil or take cuttings as described above.
- Place plants in a sunny location indoors. Supplemental lights can be used if there is not adequate natural light.
- Water the plants regularly during the rooting stage. Once roots form, allow the plant to dry out between waterings. When the top inch of soil becomes dry, water until it starts to flow out of the bottom drainage holes.
- To increase humidity around the plants, place a shallow pan of gravel and water underneath the containers.
- Since the plants will not be actively growing indoors, they will need little to no added fertilization during this period.
- Gradually acclimate plants to outside weather in the spring (harden off), by setting them outside during the day once temperatures are over 60 F. Plants can be placed outside full time once the threat of frost has passed.
Tropical plants such as cordyline, gardenia and croton, as well as some herbs like sage, rosemary and bay, can also be overwintered by bringing them indoors before the first frost.
As with all gardening, the process of overwintering tender perennials is trial and error. You may find some plants are easier than others. Keep your thumb green all winter by caring for your garden plants and possibly saving some of your favorite garden performers.