How do I over-winter heliotrope in southwest Ontario?
Heliotropes are considered tender perennials, meaning that they are hardy in warm climates but will die during Ontario’s cold winters. Plants are easily damaged by frost and their root system is not as resilient as that of true perennials. Accordingly, heliotropes are often treated as annuals and generally end up on the compost pile after they finish blooming in September or so.
If you cannot bear to part with your plants, you could pot them up and bring them inside to over-winter as houseplants. Don’t let the temperature go below 8 degrees C (45 degrees F); keeping them at a higher temperature of 16 degrees C (60 degrees F) can promote early flowering. Keep the plants just moist – don’t overwater.
Alternatively, you could also take cuttings – see the “Home guides” reference below for step-by-step instructions.