I have a Supertunia, Royal Velvet Pentunia hybrid and a Superbena Red Verbena hybrid in a pot. Now that it is getting close to fall, can I keep them, maybe in my garage, and keep them watered to bloom in the Spring? The Red Verbena and a few Petunia are still in bloom.
Thanks for contacting the Toronto Master Gardeners. Your pot of petunias and verbena sounds really lovely so I can understand why you would like to keep them for next year. Verbena is an annual, meaning that its lifecycle is finished and it dies at the end of the summer/early fall season. Petunias are usually treated as annuals in our climate, but they are actually tender perennials, meaning that they can survive for more than a single season. However they are only tender perennials in warmer climates (Zones 7-11), so in order to survive in our climate, petunias must brought inside (a garage won’t be warm enough).
The simplest solution in terms of time and effort might be to treat your whole pot as annuals, let it go for this year and buy new plants to recreate it next year. But half the fun of gardening is trying new things ! So if you want to overwinter your petunias, here are the basic steps to do this:
- Your plants should be healthy because it will be stressful for them to move indoors.
- Bring them indoors before the frost damages the leaves.
- Cut them back by as much as half.
- Clear out any debris and check and treat them for any insects or disease.
- Water the plants thoroughly and let them drain.
- Bring them indoors and put them in a bright cool spot. Since they have probably been in a sunny spot outdoors, it would be best to keep them in the shade outside for a few days to help ease the transition indoors.
- Do not fertilize or overwater them indoors. They will need less water than when they were outside.
- When active growth starts in the spring, lightly fertilize and prune if they are leggy.
- Introduce them slowly back to the outdoors.
Another method for overwintering is to take cuttings from plants and grow them indoors during the winter. However Supertunia, Royal Velvet Petunia hybrid and Superbena Red Verbena hybrid are all patented plants (this is usually indicated on the tag in the pot when you buy the plant), so taking cuttings is illegal.
Good luck with your pot, whatever method you choose !