The Four O’Clock flower (Mirabilis jalapa) is a total sun-seeker, which makes sense given its tropical South American roots. But here’s a pro tip: even if you live in a cooler climate, you can keep these beauties going year after year if you know how to overwinter their tubers properly.
Fun Facts About the Four O’Clock Flower
Four O’Clocks are upright, bushy perennials that usually reach between 2 and 3 feet tall. You can enjoy their unique blooms from June all the way through October. These little trumpet-shaped flowers come in a wild variety of colors—red, yellow, orange, white, and pink—and sometimes you’ll even see multiple colors on the same plant!
True to their name, they don’t wake up until late afternoon, which is when they release a lovely, sweet fragrance. They stay open all night and wilt by the next morning. But don’t worry about the mess; the plant is such a prolific bloomer that the old flowers shrivel up quickly to make room for a fresh batch every single day.
When it comes to soil, these plants love a fresh, slightly sandy mix packed with humus and nutrients. This gives the tuber plenty of fuel to grow during the summer. Just watch out for “wet feet”—they hate standing water. If you’re growing them in pots, make sure you have great drainage at the bottom to keep them happy.
How to Overwinter Your Four O’Clocks
As summer winds down, the blooming season comes to an end. Around October, you’ll notice the leaves starting to turn yellow. This is actually the plant’s way of moving its last bit of nutrients down into the tuber to store energy for next year. Once those night temperatures start dipping below 50°F (10°C), it’s time to move the tubers into winter storage. A cool, dry spot like a basement, garage, or frost-free garden shed is perfect. Here’s your step-by-step guide to tucking them in for the winter:
- Use a garden fork to gently lift the tubers out of the ground.
- Brush off any loose dirt. Keep them dry—don’t spray them down with a hose!
- Trim back any remaining stems and small roots attached to the tuber.
- Let them air dry on a wooden shelf or a wire rack for a bit.
- Store them in boxes filled with sand or sawdust.
- Move the boxes to your cool, dark storage spot.
- Give the tubers a turn every two weeks.
- If your storage room is really dry, give them a light misting of water every now and then.
- Keep an eye out for any signs of rot or pests.
Once spring rolls around and you see the tubers starting to sprout, you can start them in pots indoors. Wait until mid-May—after the last threat of frost has passed—before moving them back out into the garden.
