Ornamental · Linderniaceae
Wishbone Flower
Torenia fournieri
Give it shade and steady moisture, and wishbone flower blooms from summer to frost.
Partial shade
Every 2–4 days
64–86°F · 18–30°C
USDA 2–11
Overview
Wishbone flower earns its name from the pair of stamens that arch together inside each bloom like a tiny wishbone. It's a shade-loving annual that flowers in cool blue, purple, pink, and white, and it keeps going from early summer until frost. Few plants give you this much color where the sun barely reaches.
Most garden annuals demand full sun, but this one is built for the other side of the yard. It thrives under dappled light and in part to full shade, which makes it a go-to for beds along a fence, the north side of a house, or a container on a shaded porch. In hot regions it does best with morning light and a break from the harsh afternoon.
It asks little once it's settled in. Keep the soil moist, pinch it now and then to stay bushy, and it carries on flowering with no deadheading. The main thing to watch is drainage, because soggy roots are the one weakness of an otherwise easygoing plant.
Care
The short version: part to full shade with a break from hot afternoon sun, soil kept evenly moist with about 1 to 1.5 inches of water a week, rich well-drained ground, and a pinch now and then to keep it full.
Light
This is a shade plant, happiest in part to full shade or dappled light. In a hot climate, give it morning sun and afternoon shade. Push it into too much direct sun and the stems stretch and the flowers thin out.
Water
Keep the soil evenly moist, never letting it dry out between waterings. That works out to about 1 to 1.5 inches of water a week, and a layer of mulch keeps the roots cool when the heat climbs.
Soil
Plant in rich, organic ground that holds moisture but still drains freely. A slightly acidic pH of 6.0 to 6.5 suits it best, and good drainage is the one thing it won't forgive.
Temperature
It grows well across a wide range, from about 64°F to 86°F (18°C to 30°C). It's tender, so frost ends it, and the worst summer heat is easier on it with some shade and steady moisture.
Humidity
Ordinary outdoor humidity suits it fine, so there's no number to hit. Air movement matters more, since still, damp air in the shade is what invites powdery mildew.
Feeding
Mix a complete slow-release fertilizer into the bed at planting and that carries it a long way. You can feed again at roughly 6-week intervals through the growing season if the plants look like they want it.
Pruning
Pinch back the new growth now and then to keep the plant bushy and compact instead of leggy. You can skip deadheading entirely, because the flowers are self-cleaning and drop on their own.
Size & spacing
Plants stay small, reaching 6 to 18 inches (15 to 46 cm) tall and spreading 6 to 9 inches (15 to 23 cm) wide. That tidy size makes them a natural for edging, containers, and the front of a shaded bed.
When to plant
Wishbone flower is a frost-tender annual, so its season runs from the last spring frost to the first one in fall. Start seeds indoors in late winter, set the plants out once the cold has passed, and they flower from early summer until frost ends the show.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Start seeds indoors 6 to 8 weeks before the average last frost date.
- Plant: Transplant outdoors after danger of frost has passed, around mid to late April in many regions.
- Harvest: Blooms from early summer (about June) until first frost.
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Wishbone flower has few problems, and the ones it does run into trace back to soggy soil or too much sun. Read the early signs below and you can step in before a plant goes downhill. Match what you see, then act while it still helps.
Wilting and collapse with soft, dark roots
This is root rot, and it sets in when the soil stays wet or drains poorly. Dig down and you'll find roots that are brown, soft, and foul-smelling instead of firm and pale. Ease off the watering, work in something that drains better, and pull any plant that has already gone to mush.
Fix:
- Improve drainage and reduce watering frequency
- Remove and discard severely affected plants
Few flowers and long, stretched-out stems
When stems run long and blooms thin out, the plant is usually getting too much hot afternoon sun, and it may also be going unpinched. Move it where it gets morning light and afternoon shade, then pinch back the new growth to bring the bushy, flower-heavy shape back.
Fix:
- Provide morning sun with afternoon shade
- Pinch back new growth to encourage bushiness
A dusty white film on the leaves and stems
Those dusty white patches on the upper leaves are powdery mildew, a fungus that thrives in shade with still, damp air. Space the plants out, get some air moving through them, and keep water off the foliage by watering at the base.
Fix:
- Improve air circulation and spacing
- Avoid wetting foliage when watering
Toxicity
Wishbone flower is non-toxic and safe for a home with pets, livestock, and children. It isn't on the ASPCA's list of plants harmful to cats or dogs, and no part of it carries a toxin. Plant it freely where animals and kids spend time.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe around cats. A curious nibble won't poison them, though any plant can give a sensitive cat a brief, mild stomach upset.
Dogs None
No toxins here, so a dog that grazes on the leaves or flowers is in no danger.
Horses Safe
Horses can be around wishbone flower without worry, since the plant carries nothing harmful to them.
Rabbits Safe
Rabbits won't be poisoned if they browse the foliage. They may simply treat a planting as a snack.
Livestock Safe
Grazing cattle, goats, and sheep face no toxic risk from this plant.
Birds Safe
Backyard and pet birds are fine near it. None of its parts hold anything that would harm them.
People Safe
Not toxic to people. Children can play among the blooms safely, though it's grown for show rather than the table.
Varieties
Plenty of named series exist, but a few turn up most often at the garden center. These are the ones worth knowing by name.
Kauai
A compact series grown for its dense, heavy flowering in part shade.
Duchess
A compact series that blooms early and carries larger flowers than most.
Little Kiss
A small, mounding type that suits containers and the front edge of a bed.
How to propagate
Wishbone flower is easy to raise from seed, which is how nearly every gardener gets started with a fresh batch each spring.
SeedEasy
Start indoors 6 to 8 weeks before last frost, or direct sow after frost danger passes. · Several weeks to transplant size after germination.
Seed is the usual way to raise wishbone flower for spring planting. Sow indoors 6 to 8 weeks before your last frost, or sow straight into the ground once the cold has passed, and the seedlings take several weeks to reach transplant size.
Myths
Wishbone flower has to be deadheaded to keep blooming.
There's no need to pinch off spent flowers. The plant is self-cleaning and keeps blooming on its own from spring right through to frost.
Torenia needs full sun to flower well.
It's one of the rare annuals that flowers heavily in part to full shade. In a hot climate it actually prefers afternoon shade, where direct sun would stress it.