Overwintering Annuals

Overwintering Annuals

    Overwintering annuals is something I do every year, but not always with complete success. They are just so beautiful in the Fall, I can’t just let them just die.  So sometimes even against my own better judgement I haul many of them inside.

(Here are four of the nine geraniums that are presently enjoying the best light I have in the house.)    

Typically though, your house is going to have less light and less humidity than your plants are currently accustomed to so to prevent shock start bringing in your plants gradually.  I usually bring mine in for the night when temperatures start dipping to the 40’s at night. 

    The problem is every year is different. This year we got unexpected early freezing temperatures so some plants I had intended to bring in…never made it. (I still saved more than is probably practical...so don't feel sorry for me.)

    Garden rooms or greenhouses are ideal, but probably not the reality for most of us.  So put your plants where they will receive the best light or under grow lights if you have them. 

    Overwintering annuals and tender perennials would benefit from about twelve hours of light daily, but in the dark North this isn’t always possible from sunlight alone so grow lights are helpful if you can afford them.

    The irony is you bought tropical annuals in in the first place because you couldn’t resist the lovely colors, or textures, or prices; but now you are prepared to invest mucho bucks to create a perfect tropical environment for them!  Such is the life the avid gardener!

     Placing a tray filled with pebbles and a little water under your pots will increase the humidity around your plants if your house gets very dry in the winter, and humidifiers are helpful too, but remember in the coldest, driest part of the winter too much humidity can cause your windows to start condensing water.  (In other words a little humidity is good, but too much isn’t good for your house.)

    Don’t be worried if your precious plants start dropping leaves.  This is normal from the stress they are experiencing, but if the idea is just keeping them alive until they can go outside again they should be fine.

    For me, overwintering annuals and tender perennials is pretty much a trial and error process, and I have to admit that I’ve never found a method that is truly fool proof.  A procedure that works for me one year doesn’t always work the next and what works for other people may not work for you at all.

    Every year at this time of year my soft heart gets in the way of my practical side, which says: “Just let it die!”  This is very difficult for me to do, but our house certainly can’t contain all the pots I want to bring inside.  Every year I seem to try, anyway and this year is no exception. 

     In fact this year I have gotten a little fanatical about it.  I’ve actually hauled upstairs to a vacant bedroom several bricks and two long pieces of wood that are part of a son’s abandoned bookcase from college. (At least it’s doing more than gathering dust in my laundry room-where said son originally dumped it.) 

     But I digress!  Some plants are easy to bring in.  I always bring in a couple of begonias and some of my best geraniums.  I treat them just like houseplants and they actually continue to blossom most of the winter.  If they start to leggy, just cut a few inches off the top to keep them full and compact.

My dad has always stored his geraniums in the basement for the winter.  He brings them back upstairs in early March, cuts them back and starts watering.  Voila!  They start growing right away.  (I can’t tell you how many times I’ve tried this, but never once has it worked for me.)

      I know other people who dig up their geraniums, and hang them in a cool, dark place.  They replant them in the spring, cut them back and they start growing again.  (I’ve never tried this method, but again some people swear by it.)

      Tropical plants like hibiscus can also be treated like houseplants.  Decrease the amount of water and fertilizer you give them during the winter and they’ll adapt better to your house.

    If your plant has grown quite large, it can be cut back by 1/3 or more.   I have a hibiscus that is almost 20 years old.  It is quite large now and heavy.  I have to cut it back to make room for it in the house, now. The first time I did it, it was afraid I'd kill it, but now I realize that doing this has actually helped it maintain a pleasant shape and sturdier stems. 

    Tender bulbs like dahlias and gladiolas need to be dug up, cleaned and dried off and stored in moist peat for the winter. Throw away any bulbs that are soft in the spring and replant the rest.     Sweet potato vines can be saved the same way.  Letting them get a small dose of frost is OK because it signals them to stop putting out growth.  Cut off the vines, dig them up, and let the tubers dry off.  Then bury them in peat and store in a cool dry place until spring when you can replant them again.

    The next obstacles you might face when trying to overwinter annuals and tender perennials are insects and disease. For several years now I’ve filled my laundry tubs with water and insecticidal soap.  On the day I bring in my containers, they get a 90 second dunking in this mixture.  My sister does the same thing except she uses a garbage can outside.

     We’ve both found that this usually cuts way down on strange flying moths and white flies that sometimes plague overwintering annuals.

      Insecticidal soap comes in a spray bottle, too, and can be used any time during the winter if you start to notice white flies or scale.

      Another way to overwinter annuals is to take cuttings. This works best with plants that have soft stems like coleus and oxalis.  Actually I’ve tried in on geraniums and begonias, too, but I have better luck with the first two I mentioned. 

      To take cuttings choose a nice healthy stem and strip it of its lower leaves.  Then put it in a glass of water on a windowsill.  Remember stem-no leaves in the water. In a few days you should start to see tiny roots.  When you have a good set of roots transplant your cutting into a small pot and keep in the window or under light.  Use a water- based fertilizer regularly throughout the winter and by spring you should have a bigger, healthier plant than ones you’ll probably see for sale in the garden centers.

     Overwintering annuals is fun to do and if you go into it not expecting 100% survival, everything that does survive is a bonus and it makes you feel like super woman (or man!)

     Until the next time, Thanks for reading Julie’s Garden Journal!