Ornamental · Commelinaceae
Spiderwort
Tradescantia virginiana
Easygoing in sun or shade, spiderwort opens fresh three-petaled blooms morning after morning.
Full sun
USDA 4–9
2–3 ft · 0.5–0.9 m
Overview
Spiderwort is a tough, clump-forming perennial native to eastern North America, grown for the steady run of three-petaled flowers it opens through late spring and summer. Each bloom lasts only a morning, fading by afternoon, but the plant keeps replacing them day after day. It carries grassy, arching foliage and settles in almost anywhere, from a sunny border to a shaded woodland edge.
Part of what makes it so forgiving is its range across light and soil. It flowers best in full sun yet takes partial and even deep shade, and it shrugs off clay, sand, chalk, and wet ground that would stop fussier plants. Hardy down to zone 4, it returns reliably year after year and asks for very little once it's settled.
The one quirk to expect is a midsummer slump. After the main flush of bloom the clump tends to sprawl and brown out, especially in heat, but a hard cutback brings fresh growth and often a second show in late summer.
Care
The short version: plant it in moist, fertile soil in sun to shade, water through dry spells, and cut the whole clump back hard after the first flush of flowers to keep it fresh.
Light
Spiderwort flowers best in full sun but takes partial and even deep shade without complaint. Where summers run hot, a little afternoon shade helps the plant hold up and eases the midsummer slump.
Water
Keep the soil consistently moist to occasionally wet, since this is a plant that leans toward damp ground. Water through any dry spell, especially after you cut it back, to push fresh basal growth.
Soil
It grows in just about anything: clay, loam, sand, or chalk, even wet ground and soil near black walnut. Fertile, moist but well-drained soil is the sweet spot, and it handles a wide pH from 6.0 to 8.0.
Temperature
Hardy and unfussy, spiderwort comes through cold down to about -29°F (-34°C) and shrugs off summer heat up to 95°F (35°C), though high heat is what triggers the foliage to sprawl and brown.
Humidity
Ordinary outdoor humidity suits it fine, so there's no figure to chase. Good airflow does more good here, since crowded, damp clumps are where rust and leaf spot take hold.
Feeding
This vigorous perennial needs very little. A light feed of balanced fertilizer or compost at the start of the growing season in spring is plenty, and overfeeding only encourages floppy growth.
Pruning
Deadhead spent flowers to coax a second late-summer flush. When the foliage sprawls or browns after the first flush, shear the stems back hard, then cut everything to the ground at the end of the season.
Repotting
As a garden perennial it isn't potted on, but it does need dividing. Lift and split the clump every 3 to 4 years to keep it vigorous, especially once the center starts to die out or flowering drops off.
Size & spacing
Plants reach 1.5 to 3 feet (46 to 91 cm) tall with a spread of 12 to 18 inches (30 to 46 cm). Give each clump that much room so air moves freely and the foliage stays healthy.
When to plant
Spiderwort follows the seasons in the temperate garden. Set plants out in spring once frost has passed, or put container-grown plants in during autumn, and the flowers come in from late spring through early July, often reblooming into late summer.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring after frost; container plants can also be set out in autumn
- Harvest: Late spring through early July (May-July), often reblooming into late summer; cultivars can flower June-September
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
Spiderwort rarely runs into serious trouble, and most of what you'll see is cosmetic. The midsummer flop, a little slug damage, and the odd rust spot cover nearly all of it. Match what you see below and step in before it spreads.
Leaves flop, brown, and die back by midsummer
This is the plant's natural post-bloom decline, sped up by summer heat and dry soil. Once the main flush of flowers is done, the clump opens up and the foliage tires out. Shear the stems back hard, water through any dry spell, and fresh basal growth pushes up to carry the plant into fall.
Fix:
- Shear or cut the stems back hard after flowering
- Water during dry spells to encourage fresh basal regrowth
- Allow the plant to reflush in late summer and fall
Ragged holes in the tender new growth
Slugs and snails go after the soft spring shoots, and you'll spot slime trails alongside the chewed edges. The damage runs worst in damp, shady corners. Pick them off by hand in the evening, clear away the wet debris they hide under, and set out traps or barriers if they keep coming.
Fix:
- Hand-pick slugs and snails, especially in the evening
- Reduce moist hiding spots and debris near the crown
- Use slug traps or barriers if damage is heavy
Rusty pustules or spots dotting the leaves
Damp, crowded clumps invite rust and fungal leaf spot, which show up as orange-brown pustules or discrete blotches on the foliage. Strip off the marked leaves and bin them, then thin and cut back the clump so air can move through. Keeping water off the leaves stops most of it before it starts.
Fix:
- Remove and dispose of affected foliage
- Cut back and thin congested clumps to improve airflow
Toxicity
Spiderwort is more of a skin irritant than a poison. The sap can raise an itchy rash on bare skin, so wear gloves when you cut it back or divide it, and a pet that chews the leaves may get a mildly upset stomach. Keep curious pets from making a meal of it, but a stray nibble is no cause for panic.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
Chewing the leaves or stems brings on mild stomach upset, and the sap can leave a cat's mouth or skin irritated. Watch for drooling or a bit of pawing at the face.
Dogs Mild
A dog that nibbles the foliage may drool or have a brief bout of mild GI upset. The sap can redden the skin around the muzzle where it makes contact.
Horses Caution
The ASPCA flags the genus for horses, with skin irritation the main concern. Keep grazing animals from making a habit of the foliage.
Rabbits Caution
The irritant sap can leave a rabbit with a sore mouth and a touch of stomach upset, so it's not a green worth offering.
Livestock Caution
Goats, sheep, and cattle rarely bother with it, but a mouthful of the sappy stems can irritate the mouth and gut. There's no need for alarm over a stray nibble.
Birds Caution
The same irritant sap makes the plant a poor choice around pet birds, which can react to even small amounts.
People Caution
The sap is a known skin allergen and can raise an itchy rash, so pull on gloves before you cut the plant back or divide it. No part is eaten, so the risk is to your skin, not your stomach.
Sap can cause contact dermatitis and is a skin allergen; wear gloves and protective equipment when cutting back or dividing.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Garden spiderwort comes in a tidy handful of named selections, sorted mostly by flower color and the brightness of the leaves. These are the ones worth knowing.
'Sweet Kate' (syn. 'Blue and Gold')
Deep blue-purple flowers stand out against bright golden-chartreuse foliage on a compact plant 12 to 24 inches (30 to 60 cm) tall.
'Concord Grape'
Rich grape-purple flowers sit above cool blue-green leaves.
'Zwanenburg Blue'
A vigorous Andersoniana Group selection carrying large, deep blue-purple flowers.
'Satin Doll'
Soft pink flowers open on a tidy, compact habit.
'Billberry Ice' / white-flowered forms
Clear white, three-petaled flowers brighten a shady spot.
How to propagate
Spiderwort is among the easiest perennials to multiply, whether you split an established clump or let it sow its own seed around the garden.
DivisionEasy
Spring, or in autumn after flowering · Reaches full size in 1-2 years
Division is the surest way to make more, and the best time is spring or autumn once flowering is done. Lift a congested clump and pull or cut it into sections, each one carrying its own roots and shoots. Replanted pieces fill out to full size within 1 to 2 years, and splitting the clumps every few years keeps the parent plant vigorous.
SeedModerate
Sow seed in spring; plants also self-sow readily in the garden · 1-2 years to mature, flowering-size clumps
Spiderwort sows itself with ease, so seed-grown plants take care of themselves once sown in spring, reaching flowering size in 1 to 2 years. Named cultivars are the catch, since they don't come true from seed and are better divided. Snipping back the spent flower stems reins in the self-seeding before it gets away from you.
Myths
Garden spiderwort is the same plant as the trailing inch plant houseplants.
Tradescantia virginiana and the x andersoniana garden hybrids are cold-hardy, clump-forming border perennials, hardy all the way to zone 4. The tender tropical trailing types sold as houseplants, like T. zebrina and T. fluminensis, are a different story. The hardy garden spiderworts stay well-behaved clumps, while tropical T. fluminensis turns invasive in the warm southern states and is best avoided.
Spiderwort needs full sun to thrive.
It does flower most freely in full sun, but it takes partial and even deep shade in stride. In hot-summer regions a little afternoon shade actually does the plant good, easing the midsummer flop.