November 2011 Newsletter (vol.1)   >>   Overwintering Tropical Plants

Tropical Foliage Images

As the leaves begin to fall and the winter cold moves in, it is time to decide whether or not you are going to bring your tropical plants indoors. While the easy way out is to let them freeze and simply throw them into your compost pile. The thrifty, yet more time consuming option is to bring them indoors to keep until spring. Just because you may live in a colder winter climate does not mean that you have to waste the investment you made on your colorful, dramatic looking tropicals. There are three options that you have to keep them indoors:

Take cuttings
Allow dormancy
Keep the plants active

1. Take cuttings: Herbaceous, soft stemmed tropicals such as plectranthus, coleus, and pentas can be difficult to overwinter. The best option is to take cuttings and allow the “parent” plant to die. After you take your cuttings, put the stem (no leaves) in water until roots develop or applyrooting compound. Plant each cutting in a small pot and place them in your warmest and sunniest window or under grow lights.

You will want to water these plants sparingly as overwatering can cause root diseases. Although your plants may have been insect free during the summer months, it is important to inspect your new plants regularly to detect pest populations such as aphids, whiteflies, and spider mites before they completely take over. With a little effort, you should have a whole new crop of plants to put in your gardens come spring.

2. Allow Dormancy: Tropical plants that grow from bulbs, tubers and corms, are best to be brought in right after the first light frost. Examples in this group include cannas, elephant ears and dahlias. This slight shock of cold tells the plant that it is time to go dormant! Once this happens, you can do one of two things.

For plants in containers; remove the foliage and put the container in a cool, dark place like your basement or garage. Throughout the winter you will want to keep the soil barely moist.

For summer blooming bulbs (not tulips, hyacinths etc.) that are planted in the garden. You will want dig them up, remove the leaves, and store them in slightly damp sand, bark, vermiculite or loose potting mix. Another method is to cut the stems back to about six inches and dig up the plant. Then, wash the soil from the bulbs and allow them to air dry. At this time, you can also separate any new bulbs that the plant has created. Once the bulbs are dry, put them in a well-ventilated container packed with peat moss or saw dust. With either method, check the bulbs monthly to make sure that they are not drying out, mist the storage material around them with a little bit of water and discard rotten bulbs! In the spring, re-pot the bulbs about six to eight weeks before the last frost. This allows you to get a jump start on your spring garden.

3. Keep the plants active: Hibiscus, citrus, bougainvillea and jasmine are all plants that can be kept actively growing, while living inside of your house! The key to growing tropicals indoors is plenty of light and 60-70° temperatures during the day. If you lack enough natural sunlight you may use a grow light as long as you set a timer for about 12 hours a day. Be sure to bring these plants inside before the weather turns cold. There will be an adjustment period where the plants will drop some of their leaves, don’t be alarmed. Caring for your tropicals indoors is different than caring for them outside. It will not be necessary to water as often. Plants indoors prefer to be slightly on the dry side. Give them plenty of space for air flow. Both of these measures will help prevent disease. Also try to mist the plants or keep a pan of water around the plants to keep the humidity around 30%. Just as you would if growing cuttings, you will need to monitor the plants for insects. Check your plants regularly and control any pest sightings with insecticidal soap as soon as they are detected. After a long winter inside the house, many of these plants could benefit from being pruned at least once. This helps to reshape the plant from any leggy new growth as well as giving you an opportunity to take new cuttings. Reintroduce the plants to the outdoors slowly in the spring. Too much direct sunlight or wind could stress the plant resulting in defoliation and possible death! FYI: When days get shorter all indoor plants require less water.

Overwintering tropicals can be a bit challenging at times. It’s important to remember that no home is exactly the same, so what may work for others may not work for you. Our advice is to use the trial and error method to test which option is best suitable for you. No matter how you choose to overwinter your plants, having larger and more abundant tropicals, that did not cost you any extra money to buy again, will be greatly rewarding! Good luck!

Coleus Burgandy Wedding Train Hibiscus Luna Ruby Swirl

Coleus Burgandy
Wedding Train

Hibiscus Luna Ruby Swirl

Colocasia Elena
(Elephant Ears)

References:

http://extension.missouri.edu/news/DisplayStory.aspx?N=1253

http://urbanext.illinois.edu/gardenerscorner/issue_03/Fall_03_03.cfm

http://www.hortmag.com/weekly-tips/cultivation/overwinteringplants