Common blue violet
Viola sororia · Violaceae
The familiar wild violet of lawns and woods: blue-violet flowers over heart-shaped leaves in spring. It is the food plant of fritillary butterflies.
- Size
- 8 in tall, 10 in wide
- Zones
- 3 to 7
- Light
- Full sun to shade
- Flowers
- Mid April to late May
- Pets
- No toxicity recorded
- Job in a bed
- Carpet
A bed built around common blue violet
The planner designed this bed around common blue violet when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, part sun. It chose the other plants from the 708 that suit those conditions, and says below why common blue violet stands where it does.
The plants
- 1 Common blue violet × 14, blue
- 2 Bleeding heart 'King of Hearts' × 8, pink
- 3 Swamp milkweed 'Ice Ballet' × 3, white
- 4 Bee balm 'Purple Rooster' × 3, purple
- 5 Inkberry 'Gem Box' × 1, dark green leaves
- 6 Coneflower 'PowWow Wild Berry' × 5, pink
- 7 Crocus × 5, yellow
- 8 Hyacinth 'Delft Blue' × 12, blue
Why this plant
- Nothing here is unique to it. Its leaf, flower shape and colour are all on the plan already. Its case rests on where it stands and when it performs.
Why here
- Under the taller plants. It runs back between them as living mulch: there its job is to cover the soil, not to be looked at.
- 14 plants in 4 groups (5, 3, 3 and 3). Seen again further along, the same plant ties the bed together.
Why now
- In flower for 7 weeks. From mid April to late May.
- In company. With crocus and hyacinth 'Delft Blue' in mid April: 3 kinds at once.
Planned as a cottage garden: 34 of the 34 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Common blue violet is planted in four places along the bed, which gives it rhythm. There is more common blue violet than anything else, 14 plants in all.
The planner's own design check: 13 Excellent, 3 Good, 1 Satisfactory. It flags one thing to watch: Common blue violet spreads aggressively. Each plant's details say more.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where common blue violet goes in a border
At 8 in it belongs at the front of a bed. In the planner's ten height classes it is low (6 to 12 in).
Its job: carpet. A groundcover planted in threes and fives to cover the soil: along the front, and just behind it.
A valuable native in the right place, and a weed in the wrong one. Use it in rough grass and woodland where it can spread freely; keep it out of formal beds.
- Native groundcover for wild areas
- Butterfly gardens
- Naturalising in shade
What to plant with common blue violet
Plants recorded as good partners for it, and what each pairing does:
- Wild geranium: in flower together for four weeks, from early May; tall enough (20 in) to stand behind it; happy in the same moist soil.
- Christmas fern: its dark green leaves are a setting for the flowers, before and after; tall enough (20 in) to stand behind it.
- Foamflower: in flower together for five weeks, from late April; spires rising out of its mound; happy in the same moist soil.
Questions about common blue violet
Does common blue violet need sun or shade?
Common blue violet grows in full sun (6 or more hours of direct sun a day), part sun (4 to 6 hours of sun, including some afternoon sun), part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light).
It wants soil that stays evenly moist, of average fertility, and a good soak in dry spells. It copes with soil that stays wet.
What zones does common blue violet grow in?
USDA zones 3 to 7. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Above zone 7 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does common blue violet flower in my zone?
In zone 5 it flowers mid April to late May. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 3 | Late April to early June |
|---|---|
| Zone 4 | Mid April to late May |
| Zone 5 | Mid April to late May |
| Zone 6 | Early April to mid May |
| Zone 7 | Late March to early May |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should common blue violet be planted?
8 in (20 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 10 in (25 cm), so a group knits into one patch.
It grows 8 in (20 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many common blue violet plants do I need?
At 8 in apart, set out in staggered rows:
- 27 to fill 10 square feet (about 1 m²)
- 16 for a single row 10 ft (3 m) long
- 86 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as threes and fives, along the front and just behind it.
In the bed above, the planner used 14 in four groups.
Is common blue violet poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat common blue violet?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
Will common blue violet spread?
It seeds itself about; the risk of it taking over is high. Self-seeds very freely, including from hidden pods that never open as flowers, and moves into lawns and beds. It is hard to remove once established.
What flowers after common blue violet?
Common blue violet is over by late May. These start as it finishes and carry the same spot on, so it never goes flat:
- Creeping thyme: from early June to mid July, 3 in tall, to stand in front of it and cover its fading stems.
- Lady's mantle: from late May to early July, 18 in tall.
- Astilbe: from late June to mid July, 24 in tall.
What does common blue violet look like in winter?
Common blue violet dies down, but leave the stems standing: the seed heads stand through the winter, and songbirds eat the seed. Cut them down in early spring, before the new shoots come.
Is common blue violet good for bees and butterflies?
Common blue violet is visited by pollinators, bees, specialist bees, butterflies, moths and songbirds.
It is a host plant: the caterpillars of fritillary butterflies feed on its leaves. A butterfly can only lay its eggs on its host plants, so these do more for it than any nectar flower.
It is native to the United States and Canada.
More Viola
- Bird's-foot violet Viola pedata
- Horned violet Viola cornuta
- Labrador violet Viola labradorica
- Sweet violet Viola odorata
In these guides
- Plants for wet soil and rain gardens
- Plants that grow near black walnut
- Deer-resistant plants for shade
- Deer-resistant perennials for full sun
- Pet-safe plants for a sunny border
- Pet-safe plants for shade
- Native perennials for pollinators
- Native plants for shade
- Garden plants native to Canada
- Plants for butterflies
- Plants for bees
- Plants that feed garden birds
- Low plants for the front of a border
- Groundcover plants
- Plants with blue flowers
- Plants for a white garden
- Host plants for the fritillary butterflies
Every fact on record
- Type
- Perennial
- Size
- 8 in (20 cm) tall, 10 in (25 cm) wide
- Plant
- 8 in (20 cm) apart
- Height class
- Low (6 to 12 in)
- Place in the bed
- Front
- Flowers
- Mid April to late May; blue, purple, white
- Leaves
- Medium texture, herbaceous; green
- Shape
- Mounding, self-seeding
- Hardy in
- USDA zones 3 to 7
- Light
- Full sun, part sun, part shade, shade
- Soil
- Average, evenly moist
- Water
- Moderate
- Feeding
- None needed
- Family
- Violaceae
- Comes from
- Eastern and central North America
- Attracts
- Pollinators, bees, specialist bees, butterflies, moths, songbirds
- Host plant for
- Fritillary butterflies
- Stands up to
- Deer, wet soil, black walnut
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.