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Persian Shield Plant Care: How to Grow and Maintain Vibrant Purple Foliage

Close-up of iridescent purple leaves on a Persian Shield plant.

Velvety, iridescent purple leaves give Persian Shield its unmistakable glow.

Photo Credit
jpreat
Botanical Name
Strobilanthes dyerianus
Plant Type
Houseplants
Sun Exposure
Full Sun
Part Sun
Soil pH
Acidic
Neutral
Slightly Acidic to Neutral
Bloom Time
Fall
Winter
Flower Color
Purple
Hardiness Zone
8
9
10
11
Special Features
Attracts Butterflies
Attracts Bees
Attracts Pollinators

Light, Water, and Pruning Tips for Healthy Growth Indoors or Outdoors

Written By: Lauren Landers Master Gardener and Contributing Writer

If there’s one plant that can disarm you with its stunning foliage alone, it’s the Persian shield. This tropical beauty demands attention with iridescent, purple and green leaves that seem to sparkle in the light, and a fast growth rate that makes it perfect for indoor and outdoor spaces that need extra color fast. These plants may be a little harder to keep than your average tropical, but with the simple care tips in this guide, you should be able to drop your guard and grow Persian shield plants successfully without breaking a sweat!

About Persian Shield Plants

A member of the Acanthus family, Persian shield is native to Myanmar and grows wild in warm, humid tropical forests, where it takes advantage of the dappled shade cast by taller trees and shrubs. As a cultivated plant, the Persian shield can be grown perennially outdoors as a small shrub in zones 8 through 11, but these plants are highly sensitive to cold and most commonly kept as smaller annuals in cooler locations. With a little extra attention and humidity, Persian shield plants can also be grown indoors as houseplants, where their shield-shaped leaves show best in bright, indirect light.

Textured, purple and green leaves of Persian Shield.
Persian Shield is a tender perennial that brings dramatic color to garden beds and containers. Credit: Robert Asyanto

When mature, Persian shields can grow up to 5 feet tall outside, but they stay much smaller in cold climates and containers and can be kept even more compact and bushy with regular pruning. These plants eventually produce inconspicuous purple, cone-shaped flowers in fall and winter, but these are usually pinched away as they aren’t particularly flashy and can draw energy away from the plant’s leaves and make them look dull. Even with the flowers removed, however, Persian shield plants usually look drab as they age and set flower buds, so most growers replace them every few years or grow new plants from stem cuttings.

I love growing purple plants in my garden and home, and I think Persian shields look particularly beautiful when paired with other dark, dramatic plants, such as elephant ears, velvet plants, black mondo grass, and ornamental peppers. Dark Persian shield foliage also displays well beside plants with silver-toned or chartreuse green leaves – such as sweet potato vines, lamb’s ear, coleus, and dusty miller – as well as plants with purple or orange-colored blooms, like marigolds and verbena. If you have pets afoot, you don’t need to fret about Persian shields either – they’re non-toxic to pets and humans! 

Persian Shield with deep purple leaves growing alongside green ferns.
Persian Shield adds bold purple contrast among soft green ferns in this tropical-style planting. Credit: Saryanto Yanto

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Planting

Whether you intend to grow Persian shield as a houseplant, a potted outdoor annual, or a perennial garden plant, here’s how to plant new Persian shields to give them the best chances of success.

  • Choose a good growing spot: Indoors or out, Persian shields grow best in dappled light and well-draining soil. If you’re growing Persian shields in pots, select a sturdy container at least 10 inches in diameter with drainage holes at the bottom.
  • Remove the old pot: Grasp your plant’s stems and carefully wriggle it out of its nursery pot. Watering Persian shields beforehand should make them easier to slide from their pots!
  • Use quality soil: If you’re growing Persian shields in the garden, dig a planting hole that’s slightly larger than your plant’s root ball and amend the excavated soil with some compost or aged manure. If you’re growing Persian shields in containers, select a well-draining potting mix intended for houseplants or raised beds.
  • Plant it right: Place the Persian shield in the planting hole or pot at the same depth it was growing in its old container, then fill around the roots with more soil. If you’re growing Persian shields outdoors, only plant them when nighttime temperatures are consistently above 50°F, and space plants 18 to 24 inches apart.
  • Water well: After planting, water Persian shields to help their roots settle. Outdoor plants will benefit from a bit of mulch applied around their roots, too.

Growing

Persian shields can be grown as small shrubs in warm areas where winter temperatures never dip below 45°F. In cooler spots where Persian shields are marginally hardy (zones 8 and 9), these plants can usually survive the winter if you add mulch around their roots. However, in these locations, the tops of the plants will die back with the cold and regrow in spring, leading to smaller plants overall.

In the garden, Persian shields are often grown as border plants along with annuals and perennials with contrasting or coordinating leaf and flower colors. As potted plants, Persian shields can be treated as “filler” or “thriller” plants and grown alongside vining or “spiller” plants for added vertical interest. These plants will usually not have enough time to flower when cultivated as annuals, while perennial and indoor plants are often replaced after flowering when their stems get woody and their foliage colors fade.

Water
Regular watering helps Persian shields grow better, but too much water can rot their roots. For best results, feel the soil before watering and only water these plants when the top 1-inch of soil feels dry. Indoor plants may only need to be watered once a week, but outdoor potted plants may need daily watering during summer!
Light
Persian shields can grow in full sun to part shade, depending on where you’re keeping them. In cool climates, outdoor plants usually do best in full sun, while in hot areas they benefit from partial afternoon shade. Indoor plants require at least some direct light, so place them in south-facing windows if possible.
Humidity
Outdoor Persian shields are perfectly content with a range of humidity levels as long as their roots get enough water. However, indoor plants can turn brown and crispy in dry indoor air. Placing these plants on a pebble tray or in a well-lit kitchen or bathroom can help, but they’ll grow even better when humidity levels are kept at between 50 and 70% with a humidifier.
Temperature
Persian shields don’t handle cold temperatures well and should be protected from freezing weather and drafty windows. These plants grow faster and are at their most colorful in hot weather and die back when temperatures dip below 45°F. If you’re moving Persian shields out into your garden in spring or back indoors in fall, make sure to do it when nighttime temperatures are consistently above 50°F.
Fertilizer
Nitrogen-rich organic fertilizers are best for most foliage plants, including Persian shields. You can either feed these plants once at the beginning and middle of the growing season with a nitrogen-rich granular fertilizer, or feed them monthly from spring to fall with a liquid fertilizer diluted to ½ strength.
Toxicity
These plants are non-toxic to pets and humans.

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Pests/Diseases

Outdoor Persian shields are quite resilient and rarely attract pests, including deer and rabbits. Pests and other issues are more likely to occur when these plants are cultivated indoors in pots, but most problems can be prevented with proper watering and care!

  • Pests like whiteflies, mealybugs, aphids, and spider mites are more likely to occur on indoor plants. Manage these pests by increasing humidity around your Persian shields, and treat active infestations with weekly applications of an organic soap spray.
  • Faded leaf color typically occurs after Persian shields flower and is not a cause for alarm. That said, low temperature and humidity can make Persian shields look faded, too.
  • Flopping and wilting stems may occur due to watering issues, low humidity, or extreme heat. These plants may also develop leggy stems and flop over if they’re not provided with enough light.

Potting and Repotting

Persian Shield plant growing in a container.
Persian Shield adapts well to container growing, making it easy to pot up or move indoors for the winter. Credit: Robert Asyanto

Persian shields that are grown as houseplants or as containerized outdoor plants need to be repotted every few years if you grow them perennially. Here’s how!

How Often to Repot

Repot Persian shield plants every 2 to 3 years, or when they outgrow their pots.

When to Repot

The best time to repot Persian shields is in spring, but you can repot them in fall if you’re overwintering outdoor plants indoors.

How to Repot

  • Remove the old pot: Gently lift your plant from its old pot by holding the stems and giving the pot a gentle wiggle.
  • Use fresh soil: Choose a well-draining container that’s only 1 or 2 sizes larger than your existing pot and use a quality potting mix.
  • Prune the roots: Tease apart the plant’s roots to remove most of the old soil, then use sterilized scissors to trim them back by an inch or two. Root pruning helps manage the size of these plants and keeps them from becoming unruly!
  • Pot it up: Repot the Persian shield in its new pot at the same depth the plant was growing in its old container. Then, water well and return your plant to its original growing location.

Propagation

Most growers replace Persian shield plants every few years when their leaves fade and their stems become woody. However, you can create more plants from the Persian shields you already own by propagating the plants’ stems before you throw them in your compost heap.

  • Time it right: Persian shield cuttings are usually propagated in spring to early summer, but you can also propagate them in early fall before frost kills your plants.
  • Take healthy cuttings: Harvest 3 to 4-inch-long stem cuttings from healthy, softwood Persian shield stems using a sharp, sterilized knife or pair of pruners. Make your cut at a leaf node and then remove any leaves that are growing around the base of each cutting.
  • Root in soil or water: Place the cut stem ends in a glass filled with an inch or two of water, or dip the cut stems in rooting hormone and plant them in small pots filled with a damp potting mix. Position the cuttings in bright, indirect light, refresh the water in the propagation glasses every few days, and water the cuttings in soil just enough to keep the soil evenly moist.
  • Repot if needed: Persian shield cuttings should sprout roots in about 3 to 4 weeks. If you propagated Persian shields in water, transplant the cuttings into pots filled with potting mix once their roots are about 1 to 2 inches long.

Seasonal Care
Persian shields are winter hardy in zones 10 and up, while their roots will survive winters in zones 8 and 9 if they’re covered with a 2 to 3-inch layer of mulch in autumn. In colder areas, these plants are typically discarded when they die back with frost; however, outdoor plants can be potted and brought indoors several weeks before frost is expected if you want to keep them alive through winter. If you go this route, check your plants carefully for pests before your bring them in and place them in a brightly lit window to minimize plant stress.

Both indoor and outdoor Persian shields benefit from regular pruning, which prevents floppy stems and makes plants grow bushier. Just pinch overgrown stems back to a leaf node from spring through fall, but avoid pruning plants in winter.

Wit and Wisdom

  • The genus name Strobilanthes comes from the Greek words strobilos, for “cone,” and anthos, for “flower,” and refers to the conical shape of Persian shield blooms.
  • The Persian shield’s species name, dyerianus, is a nod to the botanist Sir William Thiselton-Dyer, who served as director of the Kew Botanic Gardens from 1885 to 1905.
  • Also known as the royal purple plant, Persian shields were first cultivated as indoor and outdoor plants during the Victorian era.
     

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About The Author
Lauren Landers

Lauren Landers

Master Gardener and Contributing Writer

Lauren is a gardener, writer, and public speaker with over a decade of experience helping others learn about gardening, homesteading, and sustainable living.She combines years of practical gardening a...
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