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Cobweb Spiderwort

Tradescantia sillamontana (trad-es-KAN-tee-uh see-yuh-MON-tah-nuh)

Family: Commelinaceae Unknown Herbaceous (1-3 ft)

Cobweb spiderwort is a low-growing, perennial groundcover plant that is native to dry regions in northeastern Mexico and is a member of the spiderwort family (Commelinaceae). It is densely branched, has prostrate and ascending stems, and grows 6 to 12 inches tall and 12 to 18 inches wide. The specific epithet, sillamontana, is a Latinization of "Cerro de la Silla." This references the hill or mount near Monterrey, Nuevo Leon, where this plant is native. This plant is easy to grow and prefers partial shade but will tolerate full sun with good soil moisture. When located in an area that receives full sun in the heat of the day, the leaves can burn. It can grow in a range of soil and pH conditions; however, it prefers well-drained acidic, loamy soils. As a houseplant, it should be grown in bright, filtered light, and preferably use a loam based potting mix. Water the plant moderately during the growing season and sparingly during the winter. It is winter hardy in zones 10 to 12. Pinching the tips back will promote a bushier habit. It can take on a trailing habit if the tips are not pinched. After flowering, cutting back the plant will promote a second bloom, as well as preventing self-seeding. This plant is drought and humidity tolerant. It can be propagated by stem cuttings. The cobweb spiderwort has stems that are densely branched, fleshy, and can grow up to 16 inches long. The stems and the leaves are covered with white hairs. The leaves are a dull olive-green to grayish-green, ovate, up to 2 inches long and 1 inch wide, and have a purplish hue in full sun. The undersides of the leaves are reddish-purple. The flowers appear in the summer and are solitary, bright purplish-pink, 3-petaled, and measure about 0.75 inches wide. Although considered a tropical perennial, it can also be grown as an annual groundcover in locations that are in cooler hardiness zones. This plant works wonderfully in containers, hanging baskets or as a garden accent. Quick ID Hints: stems densely branched and covered with dense white hairs leaves are in a precise geometric shape, olive-green to grayish-green, ovate, 2 inches long, 1 inch wide, covered with white hair solitary pink-purple to magenta, 3-petaled bloom, less than 1 inch wide Insects, Diseases, and Other Plant Problems: Monitor for aphids, spider mites, thrips, mealybugs, snails, and caterpillars. Root rot can occur from overwatering. Leaf scorch can result from too much direct sun. Reseeding can be an issue that is best avoided by cutting the plant back after flowering is completed. Be aware that the Cobweb Spiderwort is toxic to humans and pets, if ingested. Keep this plant out of reach of children and pets. This plant can also cause skin redness and irritation from handling. Wear protective gloves. More information on Tradescantia .

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 63 attributes.

How it fits the guild

Guild layer 4 - Herbaceous (1-3 ft) Optimal soil pH Acid (<6.0)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Fills a similar niche Asparagus setaceus Euphorbia hypericifolia Diamond Frost® 'Inneuphdia' Lantana camara 'Miss Huff'

Full plant profile

Growing Conditions
Plant type
Annual; Ground Cover; Herbaceous Perennial; Houseplant; Succulent
Life cycle
Perennial
USDA zones
10a, 10b, 11a, 11b, 12a, 12b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Loam (Silt)
Soil pH
Acid (<6.0)
Soil drainage
Good Drainage | Moist
Available space
12 inches-3 feet
Mature size
Height: 0 ft. 6 in. - 1 ft. 0 in. | Width: 1 ft. 0 in. - 1 ft. 6 in.
Growth rate
Slow
Maintenance
Low
Canopy layer
4 - Herbaceous (1-3 ft)
Form & Appearance
Habit / form
Ascending; Erect; Prostrate
Texture
Medium
Leaf color
Gray/Silver; Green; Purple/Lavender; Variegated
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Ovate
Leaf margin
Entire
Leaf feel
Soft; Velvety
Leaf value
Showy
Leaf size
1-3 inches long, < 1 inch wide
Hairs present
Yes
Leaf detail
The leaves are olive-green to grayish-green and sometimes have a blush of purple. They are covered with dense, gray/white cobweb-type hairs making it appear almost silvery in the sunlight. The base of the leaf clasps the stem. The leaves measure 2 inches long and 1 inch wide. The leave are arranged in 2 ranks. Each leaf is 180 degrees across from the other leaf.
Flower color
Pink; Purple/Lavender
Flower value
Showy
Flower form
Solitary
Flower shape
Saucer
Flower size
< 1 inch
Flower detail
The flowers are solitary, purplish-pink or magenta, three-petaled, and appear in the terminal leaf axils. Blooms occurs during the summer.
Bloom time
Summer
Stem color
Green
Stem detail
The fleshy, succulent, thick stems that are covered with white hairs. The stems are densely branched and can zigzag.
Wildlife & Ecology
Native status
Unknown
Origin
Mexico
Distribution
Introduced: Italy and Spain
Play value
Attractive Flowers; Easy to Grow
Landscape Use
Landscape location
Container; Hanging Baskets; Houseplants; Patio
Landscape theme
Rock Garden
Design feature
Accent; Border; Mass Planting
Garden tags
#drought tolerant #easy to grow #border front #hairy stems #silver leaves #gray-green leaves #evergreen groundcover #hairy leaves #mass planting #evergreen #tropical herbaceous perennial #showy leaves #succulent #potted #showy flowers #low growing #tropical #deer resistant #container plant #interesting buds #th-touch #patio #groundcover #contact dermatitis #problem for children #problem for dogs #poisonous if ingested #problem for cats #compact
Problems & Resistance
Problems
Contact Dermatitis; Poisonous to Humans; Problem for Cats; Problem for Children; Problem for Dogs
Resistant to
Deer; Diseases; Drought; Heat; Humidity
Propagation
Stem Cutting
Poison severity
Low
Poison parts
Leaves; Sap/Juice
Poison symptoms
If ingested by humans or pets, it can cause mouth and stomach irritation. In cats, ingestion can cause diarrhea and lethargy. Contact with this plant can cause skin irritation and redness.
Toxic principle
unknown
Contact dermatitis
Yes
Toxicity summary
Low severity poison; parts: Leaves; Sap/Juice; contact dermatitis

Planted at Hunnicutt

Nobody’s planted this one yet.