Lobelia, often affectionately called “Edging Lobelia,” originally hails from the sunny landscapes of South Africa. Because of those warm roots, one of the most common questions I get is whether these beauties can survive a chilly winter outdoors. If you’re wondering how to keep your purple blooms safe until spring, you’ve come to the right place!
Lobelias are Frost-Sensitive
While lobelias are technically perennials, they are definitely not fans of the cold. They are very frost-sensitive, which means they usually need to come indoors to survive the winter. To be honest, because they are so incredibly easy to grow from seed, most gardeners I know treat them as annuals and just start fresh every year.
Pro Tip: Trying to overwinter them outside is a gamble and really only works in very mild climates (think coastal areas or protected wine regions). Even then, you’d need to provide some serious winter protection to give them a fighting chance.
How to Overwinter Your Lobelia
Before you get started, you’ll want to double-check that you actually have a perennial variety. If yours is an annual type, it won’t survive the winter regardless of what you do.
Pro Tip: Not sure which variety you have? Don’t sweat it! It’s often easier to just save yourself the effort and replant from seed. You can start your seeds as early as January indoors. Just remember: these little guys can’t handle frost, so don’t move them out to the garden until mid-May once the threat of a late freeze has passed.
The Perfect Winter Spot
If you do decide to bring your lobelia inside, it needs a spot that is bright but cool. Aim for temperatures between 40°F and 50°F (5°C to 10°C). A heated living room is actually too warm for them; a cool greenhouse or an unheated (but frost-free) sunroom is much better.
When to Bring Them In
Keep an eye on the forecast! As soon as the first night frosts are predicted, it’s time to dig your lobelia out of the garden bed and bring it inside. This is also the perfect time to trim back any withered or dead foliage.
Winter Care Tips
Even though it’s “resting,” your lobelia still needs a little love. Keep the soil consistently moist—you never want the root ball to dry out completely. However, they drink much less in the winter than they do during those hot summer months, so be careful not to overwater. You can also skip the fertilizer entirely until spring rolls around!
