Cobweb Spiderwort
Known as Tradescantia Sillamontana
Spiderwort is a wildflower characterized by a grass-like form with long, strappy leaves and pretty quarter-sized, three-petaled flowers that open in the morning and close by early afternoon, each bloom lasting just one day. The plant thrives in moist but well-draining soil but is otherwise unfussy, growing well in both sunny and partially shady environments and a variety of soil conditions and pH levels. Spiderwort is considered mildly toxic to humans and pets.12
Spiderwort Care
Here are the basic steps to successfully growing spiderwort.
- Plant in a sunnier spot for more blooms.
- Water so the soil is moist but well-draining.
- Feed the plant once in the spring.
- Keep most types of spiderwort in the ground rather than pots because this sprawling plant is fast-growing.
Light
Spiderwort is not overly picky about available sunlight. While the plant prefers partial shade, it does well in almost any environment, as long as it gets a few hours of light per day and enough water if exposed to all-day sunlight. Depending on how much sunlight your spiderwort gets, you will notice a difference in the amount and frequency of blooms, so choose a sunnier spot if you want a showy plant.
Soil
Spiderwort is easily grown in almost any soil condition, as long as it is moist but well-draining—it thrives best in humusy soil that’s slightly acidic with a pH of 6.8 to 7.2. Because the plant clumps and sprawls as it grows, plant it in the spring 4 to 6 inches deep in the soil with about a foot or more between each plant for ample room.
Water
While spiderwort is a drought-tolerant plant, it does best in moist soil that’s watered every few days, especially during the hotter summer months. However, frequent summer storms will provide enough rain to keep your spiderwort plants happy.
Temperature and Humidity
Spiderwort is not fussy when it comes to its temperature and humidity conditions. It has adapted to a range of hardiness zones and temperatures, allowing it to thrive from early spring to late summer.
Fertilizer
A single application in early spring at the beginning of its growing period is usually sufficient for outdoor spiderwort plants. Follow the product label instructions for the amount to use. Add compost to the soil for additional nutrients throughout the summer.
Types of Spiderwort
Many tradescantia varieties in nurseries are hybrids developed by breeders and focus on leaf and flower color. They include:
- Tradescantia ‘Amethyst Kiss’: This trademarked variety has purple-blue blooms that can grow in full sun, partial shade, and full shade.
- Tradescantia ‘Concord Grape’: The spiderwort type has pinkish-purple flowers and blue-tinted leaves suited to full sun or partial shade.
- Tradescantia ‘Red Grape’: It has bright rose-colored flowers and a compact, mounded growth habit.
- Tradescantia ‘Sweet Kate’: This type stands out by its bright yellow leaves that contrast well with its saturated blue flowers.
- Tradescantia ‘Purple Profusion’: This spiderwort has multiple buds and purple-tinged foliage when it’s young.
Pruning
Spiderwort can look ragged after its bloom period is over. Shearing the plant back by one-third (leaving around 8- to 12-inch stems) or de-leafing to new growth will reinvigorate the plant, increase late-season blooms, and make it look more presentable. Shearing the plant in mid-season also prevents spiderwort from self-sowing and becoming weedy. When shearing, you’ll notice secretions that harden to look like spider webs, which is how the plant got its common name.
Propagating Spiderwort
Spiderwort will readily self-seed but starting plants from seeds is tricky and yields unpredictable and disappointing results. The easiest and most recommended way to propagate spiderwort is to divide large clumps in the fall or early spring. Take these steps.
- Lift the entire plant out of the ground with a shovel. If the plant is too big to move in one piece, do it in sections.
- Shake off any excess soil and separate the clump into smaller sections.
- Dig a hole deep enough to replant each section at the same depth as the original plant. Backfill with soil.
- Keep them well-watered until you see new growth.
Potting and Repotting Spiderwort
There are about 75 species in the Tradescantia genus, including houseplants and perennial wildflowers. Certain spiderwort plants, such as Tradescantia zebrina, are grown as virtually carefree houseplants for their foliage. Those types of spiderwort plants look best in hanging containers near indirect light. Make sure the plant is in a container with drainage holes at the bottom since it needs well-draining but moist soil. Pinch the plant regularly for bushy growth and pick out the dead leaves as they appear. The plant will likely last a few years indoors so you probably won’t need to repot spiderwort.
Common Pests and Plant Diseases
Spiderwort does not attract many pests or diseases. However, be on the lookout for spider mites. Treat the problem with a spray of water or neem oil. Snails and caterpillars may snack on younger spiderwort plants—remove them by hand or with neem oil.
Spiderwort does not like soggy soil and may respond with root rot and leaf spot problems from fungal growth.
How to Get Spiderwort to Bloom
Bloom Months
Spiderwort blooms from late spring into mid-summer and possibly all summer into the fall.
What Do Spiderwort Flowers Look and Smell Like?
Spiderwort is a small indigo-blue or lavender flower with three petals. Spiderwort flowers form in clusters. They have a subtle, sweet scent.
How to Encourage More Blooms
Spiderwort is a prolific bloomer in its first year and soon after planting. It’s unlikely this plant will fail to bloom. However, the more sun the plant gets, especially in the spring and early summer, the more it will bloom. If blooming slows down, cut it back by a third to rejuvenate the plant. Deadheading may be necessary to encourage repeated blooming of your spiderwort.
Common Problems With Spiderwort
Spiderwort plants are easy to care for, which makes them beloved additions to any garden. However, take note of the following problems.
Curling, Drooping, or Yellowing Leaves
Foliage problems usually occur from overwatering. Spiderwort is sensitive to soggy conditions. Overwatering will lead to root rot and damage to leaves, as well.
Browning or Limp Leaves
This is the opposite problem where the plant is not getting enough water. Give the spiderwort a good soaking to revive it.
Leaves Falling Over or Severly Drooping
Spiderwort plants are not very strong upright plants. So when the leaves fall over, severely droop, or even fall off, it’s typically a sign of a lack of light, overwatering, or pest infestations (such as spider mites).
Leaves Losing Color
If you have a spiderwort with purplish or yellowish foliage, it may need more sun if the leaves are losing their intended color.
FAQ-
Should spiderwort be planted in the sun or shade?
Spiderwort grows in both sun and partially shady conditions. However, give the plant more sunlight for the best blooms.
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Are spiderworts invasive?
The plant is considered invasive in some parts of the country and they tend to self-sow enthusiastically. If you’re worried about containing the spread, you can shear the plants back after their last flowering so they don’t have a chance to go to seed.3
White-flowered spiderwort. Invasive Plant Atlas of the United States.
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Should I cut back spiderwort?
Cut back spiderwort in the summer after it finishes blooming and begins to look tattered. This will refresh and coax the plant into a second flush of flowers.