It’s easy to see where this exotic plant got its common name of ‘Persian shield,’ as the leaves are perfectly shield-shaped, and the iridescent purple foliage has a shimmering quality that makes it appear silver in some lights. Interestingly though, the plant hails from Myanmar (formerly Burma), and not Persia, as its name suggests.
The plant features unusual, striking foliage, which adds vibrant color to gardens and homes all year around. It works well in containers, flowerbeds, or as a houseplant, enjoying warm temperatures, moist soil, and high humidity. The sap of the plant is a mild skin irritant, so take care when handling (Missouri Botanical Gardens).
Persian Shield Overview
|Scientific Name||Strobilanthes dyeriana|
|Type||Evergreen perennial flowering plant|
|Common Names||Persian shield, Royal purple plant, Bermuda conehead|
|Height||Up to 4 feet|
|Light||Full sun to partial shade|
|Watering||Maintain moist soil|
|Pests||Whitefly and aphids|
Caring for Your Persian Shield
Persian shields like to be kept in consistently moist soil. They are not drought-tolerant, so you will need to keep on top of watering the plant to make sure it doesn’t dry out. When kept as a houseplant, you can expect to water your Persian shield at least twice a week, though always dip your finger into the soil to see if it is ready to be watered. Only water the plant once the top layer of soil has dried out. Otherwise, you risk drowning your plant and causing root rot.
Pay extra attention to your plant’s watering needs in the winter, when indoor heating systems may cause the soil to dry out faster than usual. For outdoor plants, moist soil should also be maintained. Water regularly throughout summer, especially in times when rainfall is lacking.
Outdoor Persian shields will probably need to be watered more frequently than those kept as houseplants, as the summer heat will cause the moisture from the soil to evaporate more quickly. To battle this, you can mulch the topsoil of your Persian shield, as this helps to prevent moisture from evaporating.
As these are thirsty plants, you will need to ensure they are grown in well-draining soil to prevent them from sitting in waterlogged boggy conditions. Add grit or sand to your soil to increase its drainage capacity, though don’t go overboard because a soil that drains too quickly will struggle to meet the Persian shield's demand for water.
Add organic matter such as well-rotted compost to your soil, as this will help to hold onto water near the plant's roots while still allowing it to drain effectively. It will also help to replicate the plant’s natural environment, as it is used to growing in rich soils in its native habitat.
When grown outdoors, the Persian shield can tolerate full sun, though it prefers partial shade. In its natural habitat, it would grow under the partial shade of overhead trees, so it’s best to try to replicate this as best you can in your own garden. Ideally, recreate this environment by planting the Persian shield under the protection of other trees, which can provide dappled shade.
If you must plant it in a sunny spot, ensure it gets afternoon shade to protect it during the hottest time of the day. If the plant gets too much sun, it will struggle to produce the vibrant purple foliage it is loved for.
If you find that your Persian shield is dull in color, consider moving it to a position with more shade. When grown as a houseplant, set the Persian shield in a window that receives bright, indirect light. You will need to try to provide a good balance between bright light and shade. Too much shade, and the plant will lose its color, but too little sun, and it will become leggy as it tries to find a source of light (Royal Horticultural Society).
Persian shield is hardy from USDA growing zones 9 through 12, where it will grow as a perennial. It can be grown in zones 7 and 8, though it will grow as an annual. In these cooler climates, the plant will die back in the winter, but as long as the root system doesn’t freeze and die, then it will bounce back to life in the spring.
To help prevent the roots from freezing, you can insulate the soil by mulching it over before the first frost or use a horticultural blanket to protect the plant from cold temperatures. Alternatively, if the plant is grown outdoors in a container, you could bring it indoors during cooler months to overwinter it.
In cool climates, the Persian shield is most commonly grown as a houseplant, where it will provide bright foliage all year-round. In some instances, if the plant is warm enough, it will flower during winter, though most people agree that the flowers are insignificant compared with the colorful foliage. When kept indoors, the plant should be kept at a temperature above 60 °F.
Persian shields rely on high humidity to thrive. This is fairly easy to replicate if your Persian shield is kept as a houseplant, and there are a few options you can choose from when it comes to increasing the humidity levels in your home.
If you enjoy tending to your plants, then daily misting might be a good option. This simply involves lightly spritzing your plant's foliage with water, though if you are a busy or forgetful person, then this method isn’t for you, as a few missed days of misting could negatively affect your plant's health.
For a less involved option, use a pebble tray to increase humidity. Simply set your plant on a tray filled with pebbles and water. The water level must be lower than the tallest pebbles so that it does not reach the base of the plant pot and get sucked up through the drainage holes. This method works because as the water evaporates from the pebbles, it increases the humidity around the plant. You will just need to ensure that the water in the tray is kept topped up.
Another easy, though a more costly option, is to use an electric humidifier. These can be plugged in and will increase the moisture content of your air throughout the whole room. Finally, always group your humidity loving plants together, as this also helps to improve humidity.
Dry air tends to become more of a problem during the colder months when heating systems dry out the air in our homes, so pay extra attention to increasing humidity during these times. Also, take care to keep your plant away from any heating vents, which will dry the plant out.
If your Persian shields are growing outdoors, you can place bowls of water near the base of the plants as this will have a similar effect as a pebble tray.
Persian shields can be propagated from seed or through stem cuttings. Seeds need to be kept warm in order to germinate, so you can sow seeds outside in spring in warm climates, or sow them indoors with the use of a bottom heater. Ideal temperatures for germination of these seeds is between 55 and 65 °F.
To propagate from stem cuttings, take a cutting of around 3 inches in length from the end of a stem, cutting at the point just below a node. Dip the raw end in rooting hormone, then plant it in a moist growing medium and cover over with a plastic bag to mimic the conditions of a greenhouse. Check on the cutting every day, misting to keep it moist if necessary.
After a few weeks, roots will have formed, at which point you can remove the plastic bag. Let it grow uncovered for another week or two, then transplant it into a larger pot. You can then keep the cutting to grow as a houseplant, or plant it outside.
When kept in a container, the Persian shield will need to be repotted every year when young. The best time to do this is in early spring, moving the plant to a container just one size up from its current container. Once the plant is older, you can reduce repotting to every other year. If kept indoors, you may want to slow the growth of the plant to keep it at a manageable size. To do this during repotting, you can trim back the root ball. Doing this will stunt the growth of the plant without causing it any damage.
Persian shields have a tendency to grow leggy and spindly, which can look unattractive. To prevent this from happening, pinch back the leaves in early spring to encourage a fuller and more bushy growth. If your plant blooms, you may wish to remove the flowers as they appear. Most people find the flowers uninteresting compared with the colorful foliage, and pinching off the flowers will ensure the plant's energy focuses on leave production rather than blooming.
Do you have any questions about Persian Shield? If so, leave us a comment, and don’t forget to this page with other growers!