Ohio spiderwort
Tradescantia ohiensis · Commelinaceae
Three-petalled flowers of clear blue open each morning and close by afternoon, on tall, smooth, blue-grey stems with grassy leaves.
- Size
- 2½ ft tall, 18 in wide
- Zones
- 4 to 9
- Light
- Full sun to part sun
- Flowers
- Late May to mid July
- Pets
- Toxic (mild)
- Job in a bed
- Drift
A bed built around ohio spiderwort
The planner designed this bed around ohio spiderwort when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why ohio spiderwort stands where it does.
The plants
- 1 Ohio spiderwort × 3, blue
- 2 Sedum 'Lidakense' × 20, pink
- 3 Winter heath × 4, white
- 4 Brown-eyed Susan × 5, yellow
- 5 Silver sage × 1, silver leaves
- 6 Scarlet coral bells × 3, red
- 7 Crown imperial × 3, orange
- 8 Dutch iris × 10, purple
Why this plant
- The only open bowls. The others are dense clusters, bells, daisies and others. Shape reads at a distance, where colours blur.
- The only blue.
Why here
- At the back. At 2½ ft it is seen over scarlet coral bells (18 in) in front of it, and has nothing behind it to hide.
- A step in the back row. Next to crown imperial (3½ ft) and brown-eyed Susan (4 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 3 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
Why now
- In flower for 8 weeks. From late May to mid July.
- Part of the bed's peak. With scarlet coral bells and Dutch iris in late May: 3 kinds at once. No week has more.
Planned as a cottage garden: 29 of the 36 plants (81%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. The most in flower at one time is 3 kinds, from late May. For contrast, the bold leaves of silver sage sit beside the fine leaves of winter heath.
The planner's own design check: 12 Excellent, 5 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where ohio spiderwort goes in a border
At 2½ ft it belongs in the middle of a bed. In the planner's ten height classes it is medium tall (2½ to 3 ft).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
A prairie native, taller and more drought-tolerant than garden spiderworts. Cut it to the ground when it looks tired in July, and it returns for autumn.
- Prairie and meadow planting
- Blue for early summer mornings
- Dry, sunny borders
What to plant with ohio spiderwort
Plants recorded as good partners for it, and what each pairing does:
- Butterfly weed: blue against orange, opposite each other on the colour wheel, in flower together for three weeks.
- Pale purple coneflower: in flower together for five weeks, from mid June.
- Little bluestem: its blue-green leaves are a setting for the flowers, before and after.
Questions about ohio spiderwort
Does ohio spiderwort need sun or shade?
Ohio spiderwort grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).
It wants ordinary well-drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.
What zones does ohio spiderwort grow in?
USDA zones 4 to 9. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does ohio spiderwort flower in my zone?
In zone 5 it flowers late May to mid July. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 4 | Late May to mid July |
|---|---|
| Zone 5 | Late May to mid July |
| Zone 6 | Mid May to mid July |
| Zone 7 | Early May to early July |
| Zone 8 | Early May to early July |
| Zone 9 | Late April to late June |
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 ohio spiderwort be planted?
16 in (40 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 18 in (45 cm), so a group knits into one patch.
It grows 2½ ft (80 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many ohio spiderwort plants do I need?
At 16 in apart, set out in staggered rows:
- 7 to fill 10 square feet (about 1 m²)
- 8 for a single row 10 ft (3 m) long
- 21 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used three in one group.
Is ohio spiderwort poisonous to dogs and cats?
Yes: mild toxicity to people, dogs, cats and horses. The sap can irritate the skin of people and pets.
Rated from NC State Extension. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like ohio spiderwort?
These come closest to doing what ohio spiderwort does, and no toxicity is recorded for them:
- Meadow sage: the same job in a bed, the same flowering time and the same colour; 8 in shorter, medium leaves, not fine.
- Beardtongue 'Husker Red': the same job in a bed, the same size and the same flowering time; white, not blue, medium leaves, not fine.
- Musk mallow: the same job in a bed and the same size; flowers late June to late August, pink or white, not blue.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat ohio spiderwort?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
Will ohio spiderwort spread?
It seeds itself about; the risk of it taking over is moderate. Self-seeds freely in open soil. Cut it back after flowering to limit seedlings.
What flowers after ohio spiderwort?
Ohio spiderwort is over by mid July. These start as it finishes and carry the same spot on, so it never goes flat:
- Black-eyed Susan: from mid July to mid September, 24 in tall, to stand in front of it and cover its fading stems.
- Lilyturf: from early August to mid September, 16 in tall, to stand in front of it and cover its fading stems.
- Bee balm: from early July to early August, 3 ft tall.
What does ohio spiderwort look like in winter?
Ohio spiderwort dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.
Is ohio spiderwort good for bees and butterflies?
Ohio spiderwort is visited by pollinators, bees and butterflies.
It is native to the United States and Canada.
More Tradescantia
- Spiderwort Tradescantia x andersoniana
- Spiderwort 'Sweet Kate' Tradescantia 'Sweet Kate'
In these guides
- Drought-tolerant perennials for full sun
- Garden plants toxic to cats
- Garden plants toxic to dogs
- Native perennials for pollinators
- Garden plants native to Canada
- Plants for butterflies
- Plants for bees
- Plants with blue flowers
Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial
- Size
- 2½ ft (80 cm) tall, 18 in (45 cm) wide
- Plant
- 16 in (40 cm) apart
- Height class
- Medium tall (2½ to 3 ft)
- Place in the bed
- Middle
- Flowers
- Late May to mid July; open bowls; blue, purple
- Leaves
- Fine texture, herbaceous; blue-green
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 4 to 9
- Light
- Full sun, part sun
- Soil
- Average, well-drained
- Water
- Low
- Feeding
- None needed
- Family
- Commelinaceae
- Comes from
- Ontario to Central and Eastern United States
- Attracts
- Pollinators, bees, butterflies
- Stands up to
- Drought
Checked against NC State Extension and VASCAN (plants of Canada). 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.