A few years ago, I shared my plan to overwinter some frost-tender tropical plants from my outdoor collection. I was not successful with the bougainvillea featured in that post, but I’ve learned a lot since then, mainly from a group of experts on Facebook.
It is advised (by said experts mentioned above) to shake the outside dirt off of the roots and then to give them a good rinse with a strong jet of water from your hose before bringing the plant inside. This practice loosens the root ball so the roots can stretch out in their new location.
This works especially well on houseplants that need to be repotted to larger pots too. When examining the roots of tender annuals and houseplants, remove any rotted or dead roots.
Prevent Bugs From Overwintering in Your House Too
The last thing you want to welcome into your home for the winter is bugs. Adult bugs and their eggs will come in if you do not treat the plants, soil, and roots that you bring in. I don’t mind the tiny (the size of fruit flies) buggers flying around, but my husband and grandchildren hate them.
There are several ways to eliminate both the adults and eggs. Insecticidal soap or a solution of hydrogen peroxide works well on the plants and soil. Sticky traps will catch adults preventing them from laying any more eggs. These sticky traps also work well on fruit flies.
Tropicals I’m Attempting to Overwinter this Season
This fall I pulled up three tropical plants that I used as the thrillers in containers.
I find it frustrating (and sad) that these beautiful plants are just achieving that mature, settled-in look when frost ruins them in our zone 4 to 5 gardens. This year I decided to remove the thrillers, rinse their roots with water as advised above, spray them several times with insecticidal soap, then bring them inside.
My biggest challenge was finding sunny spots for them to overwinter. My south and east-facing windows were already houseplant-loaded. It took a bit of shuffling to find spots for three (more) large plants.
Hopefully, they survive until I can reuse them in the spring.
I also took more cuttings from fully mature annuals this fall. Like the tropical “thrillers” in the center of my containers, the fillers and spillers were gorgeous this year too. Especially the coleus, which continues to be my favourite annual for containers in shady spots.
They are all set up in perlite on my basement counter; as soon as roots form I will pot the baby plants up so I have a collection to use in spring. For those of you not familiar with perlite, it is a form of volcanic glass with a high water content, used to propagate plants without soil.
Digging up Dahlia Tubers
Another new thing I am trying this year is digging up the dahlia bulbs I planted in the spring. I have always admired dahlias in everyone else’s gardens, so decided to try them myself this year. My granddaughters loved the various colours and shapes that bloomed right up until this past week when our first frost descended on us..
I followed the same guideline with the dahlia tubers as I did for the roots of the other annuals I am overwintering. Digging up and rinsing well with a hose. The difference here is that I had to leave these lying in a single layer on the floor of my garage to dry before storing them in a box in a cool, dark spot.
All of my overwintering preparations are complete, now I just have to wait until spring to see how successful I have been. Have you had any success with overwintering frost tender plants?