How to Plant, Grow, and Care for Persian Shield
Are you thinking of adding a persian shield to your indoor or outdoor garden? These beautiful plants have some of the most visibly stunning leaves you'll lay eyes on. In this article, gardening expert and houseplant enthusiast Madison Moulton shares all you need to know about Persian Shield plants, including their maintenance and care needs.
Colorful foliage is a wonderful addition to beds and containers, providing interest year-round when the rest of the flowers in your garden die back. And if purple is the color you’re looking for, Persian Shield is the perfect plant for you.
This plant is typically grown as an annual but can survive as a perennial in warmer climates. Thanks to the native conditions they prefer, they also make great foliage plants for indoor growth, although they do need more light than other common houseplants.
While they are not difficult plants to grow, Persian Shield does have some specific requirements that will keep the bright leaves looking their best. Follow this guide to give your plant the best possible care this year.
Persian Shield Plant Overview
Plant Type Annual/Tender Perennial/Houseplant
Species Strobilanthes dyerianus
Native Area Myanmar
Exposure Partial – full sun
Watering Requirements Moderate
Pests and Diseases Aphids, spider mites, mealybug
Soil Type Slightly acidic, well-draining
Hardiness Zone 9-11
About Persian Shield
Persian Shield is scientifically known as Strobilanthes dyerianus, with the specific epithet named after botanist and third director of the Royal Botanic Gardens William Turner Thiselton-Dyer. You may also see it called the royal purple plant after its captivating hue.
Strobilanthes dyerianus is a tender perennial native to Myanmar (formerly Burma). This native habitat means it is usually grown outdoors in warmer climates or as an annual in cooler climates. Some gardeners choose to keep it as a houseplant too to protect the sensitive growth from temperature dips in fall and winter. They can also provide interest indoors over the cooler months when they begin to flower, although flowering is not always guaranteed.
Although Persian Shield can add blooms to your garden when other flowers typically die down in winter, the blue flowers are somewhat insignificant when compared to the foliage.
Strobilanthes dyerianus sports a deep and almost luminous purple color year-round, made even more captivating by contrasting green veins. Some leaves have a silver sheen to them too, adding to the unique look.
If you’re looking for a pop of color in your indoor garden or even in your outdoor garden beds, this is the plant to grow. They also look wonderful in containers, especially when combined with other cascading plants to complete the look.
After a few years their looks do begin to fade, so if you’re growing as a perennial it’s best to replace the plants over time. Luckily, they can be propagated from cuttings, allowing you to grow your supply.
As Persian Shield is sensitive to cold, it’s best to plant in spring once the weather has warmed. If you’re growing as an annual, plant as soon as temperatures are above 50F to make the most of a short season. Alternatively, you can plant in pots to bring the containers indoors over winter for protection.
Those that live in USDA Zones 9 – 11 (or 8 at a push) can grow Strobilanthes dyerianus as a perennial outdoors or in containers. However, the plants only look their best for a couple of years, so they aren’t particularly long-lived. Plan to replace them or propagate in future if you want to maintain the sparkling pop of color in your garden.
Although they look wonderful when planted on their own, Persian Shield stands out best amongst other leafy plants. A neutral green palette of tropical leaves will provide that purple pop of color these plants are known for. But, you can also combine them with brighter hues like red or yellow for more contrast.
Orange is another option that will intensify the purple hue, but I tend to avoid combinations of orange and purple in my beds or containers. It gives me a ‘Halloween’ feel I don’t typically enjoy year-round, but there is no doubt that the colors look good together.
These plants are normally sold in containers or bags, ready for planting once all chance of frost has passed in spring. Choose a healthy plant with no signs of disease or damage for a strong start and quick establishment.
If you are planting outdoors, follow these simple steps:
- Amend soil with plenty of compost before planting.
- If the soil drains too quickly, add more compost and peat moss or coconut coir.
- This will improve moisture retention.
- If the soil is heavy clay, amend with sand to increase drainage.
- Remove the plant from the container and gently tease the roots.
- Make a hole the same depth as the previous container and plant.
- Press down around the base to anchor the plant in place.
- Provide at least two to three feet of space around the base of the plant.
- Keep in mind that these plants grow to around three or four feet tall.
- Ensure they will not shade any nearby plants that require sun once they are fully grown.
Planting in Containers
If you are planting in containers, the process is similar, minus a few steps. Follow these steps below for container planting:
- Choose a large container that can accommodate the full size of the plant.
- If you’re planting several plants in the same container, choose one slightly bigger.
- It should also have drainage holes at the base to prevent waterlogging.
- Fill the bottom of the container with a high-quality potting mix.
- If you plan on keeping the pot indoors, add a few handfuls of perlite to improve drainage.
- Remove the plant from the container and tease the roots.
- Do the same for any companions you are planting.
- Lower the plant into the center of the container and fill in the gaps with more soil mix.
- Make sure all the plants still have some space in the container for their roots to expand.
- Fill the container until the soil line is just below the rim of the pot.
- Press around the base to stabilize the plant and roots.
- Water immediately after planting, ensuring the excess moisture flows out the bottom.
How to Grow
Identifying the perfect planting position will make Strobilanthes dyerianus an easy plant to grow. They do need a little more attention in dry climates but don’t experience too many growth problems in the right conditions.
Persian Shield grows best in partially shady spots, receiving a full day of dappled light or around 4 hours of direct sun per day. They can also adjust well to full sun in cooler regions where sunlight is not too intense.
As they grow best in partial shade, any Strobilanthes dyerianus intended to grow as perennials are best kept out of full sun. Up to six hours of direct sun is manageable, but anything more than that (especially in hot climates with intense summers) will negatively impact growth. If they receive too much sun, the leaves may begin to lose their color.
On the other hand, deep shade can also negatively affect color. Although they are found in forests in their native environments, they don’t have much cover and receive several hours of sunlight per day. Areas with deep shade will stunt growth and make the foliage appear dull.
When growing indoors, positions with a few hours of direct morning sun are preferred. Choose positions in front of east-facing windows where the plants can receive direct morning sun and bright indirect light for the rest of the day for the strongest growth.
These plants can be demanding when it comes to water. The leaves are thin and delicate, quickly wilting as soon as the soil dries out. Strobilanthes dyerianus prefer the soil to remain slightly moist at a consistent level, without becoming soggy and waterlogged.
The amount of watering required will depend on where your plant is placed. Those planted outdoors and in full sun will need water more often than those planted in partial shade.
Soil texture also plays a role in how quickly the soil dries out. You can expect to water around 1-2 times per week, depending on position and rain in your area.
Containers dry out much quicker than beds, requiring more frequent watering. Containers in sunny spots will likely need water every couple of days or as often as every day in the height of summer. The size of the container will also affect how quickly the soil dries out, so check the soil moisture before watering again.
When growing as a perennial, watering will be impacted by the seasons. Water often in summer, especially on days when temperatures are high, to prevent heat stress. Slow watering in fall and winter to prevent waterlogging.
It’s best not to wait until the plants are wilting to water. Although they will bounce back quickly, this is a sign of stress best avoided if you want your plant to perform at its best. Try not to let the soil dry out completely, watering again just before this time to prevent wilting.
Like many garden plants, Persian Shield grows best in well-draining and nutrient-rich soil. The initial application of compost at planting time will improve conditions initially, but it’s helpful to monitor soil conditions throughout the year if you’re growing them as perennials.
Applying a layer of compost once per season can help improve soil conditions over time. This also has the added benefits of retaining moisture and suppressing weeds. Make sure the mulch layer is a few inches thick to fully reap all these benefits.
These plants grow best in soil that is slightly acidic, although they aren’t too fussy about pH. In containers, high-quality potting soil is ideal, with some additional drainage materials mixed in depending on where you are planting.
Temperature and Humidity
As mentioned, these popular plants grow best in USDA Zones 9-11. They can be grown in Zone 8 if you’re careful about protecting the foliage from damage. Alternatively, as an annual, they can be grown in any climate. The leaves will simply die back in fall, at which point the plant can be pulled from the garden.
These temperature requirements do make Strobilanthes dyerianus ideal for growing indoors. Since they like the same temperatures humans do, they make wonderful purple houseplants if you have the right light levels indoors.
Ensure they are never left in temperatures below 50F, indoors and out, to prevent permanent damage to the sensitive foliage.
Due to their forested native habitats, they do need high humidity levels to grow their best and maintain their stunning leaves. If you live in a very dry climate, it’s best to grow indoors where humidity can be improved with a humidifier.
Strobilanthes dyerianus are not heavy feeders. They do need nutrients to thrive and produce lush foliage, but are happy with a moderate amount of fertilizer throughout the season. To boost leaf and stem growth, a fertilizer slightly higher in nitrogen is recommended.
If you’ve planted in beds, fertilize a few weeks after planting and again just after the start of summer. This will give your Strobilanthes dyerianus everything it needs for strong growth at the right time. A soil test will tell you if there are any nutrient deficiencies to manage with a different fertilizer.
In containers with frequent watering, nutrients tend to leech from the soil much quicker. That means they will need fertilizer slightly more often to maintain the same nutrient levels needed for strong growth.
Plants grown in containers should be fertilized around once per month with a liquid fertilizer. As growth is slower indoors, you can stretch this interval to every 6 weeks or so.
After planting, there are a few additional tasks that can help the plant grow and look its best.
The first is pinching. This process involves trimming the stems back slightly in the early stages of growth to promote branching. If you’re looking for a full and bushy plant, pinching is essential.
Cut the stems back when they are around 8 inches tall, pinching the soft growth with your fingers or trimming with a pair of shears. You can complete a second round a few weeks later, but this usually isn’t necessary.
Pruning is also beneficial to improve the overall look of the plant. When stems become leggy, trimming them back can promote new and healthy growth. Also look out for damaged or diseased leaves and trim those off the plant as soon as you spot them. These will draw energy from the plant that could be used to produce new growth.
Container plants also don’t typically require repotting, as long as their initial pot is big enough. By the time repotting comes around, the color of the leaves will likely be fading.
The stems may also not produce strong growth as they did soon after planting. In these cases, it’s better to take cuttings and plant them into new containers rather than trying to keep a fading plant going by repotting.
After a few years, your Strobilanthes dyerianus will begin to fade. If you want to keep growing these stunning plants, or maybe want to fill an entire bed without buying brand-new plants, propagation is the answer.
Persian Shield can be propagated from stem cuttings or seeds. However, as flowering is quite rare (especially when these plants are grown as annuals), stem cuttings is the easiest route. Spring is the best time to take cuttings for strong rooting and establishment before fall. Follow these steps to get it right.
Step 1: Identify the Perfect Stem
Start by choosing a healthy stem with soft growth and lush leaves. It should be free of any signs of pest or disease damage to avoid spreading the problem to your new plants. The healthier the stem, the better your chances of rooting.
It’s best to take multiple cuttings at once. This increases your chances of success overall and limits time spent propagating later on.
Step 2: Trim Below a Node
With a sharp pair of pruning shears, trim a piece of the stem around 4 inches long. Cut just below a node – the points in the stem where the leaves emerge. Your shears should be completely clean to avoid spreading harmful bacteria to the cutting and parent plant.
Step 3: Remove Bottom Leaves
Next, remove the leaves from the bottom half of the cutting to expose the nodes. This part will be buried below the soil, so it’s important the leaves are removed to prevent rotting. Keep a few leaves on the top half of the cutting to facilitate root growth.
Step 4: Root in Soil
With your cuttings prepared, it’s time to root. Strobilanthes dyerianus cuttings grow best when rooted in soil (or a soilless medium). The propagation mix I typically use is a combination of coconut coir and perlite, but you can also propagate in peat if you have some on hand.
Fill a container with this mix. Make as many holes as needed with your finger, planting the cuttings so the bottom half is buried. Press down around the soil to anchor them in place and spray the soil to moisten.
Step 5: Cover The Cuttings
To improve humidity around the cuttings and encourage root growth, create a mini greenhouse by covering the pot with a clear plastic bag. It should not touch any of the leaves – if it begins to collapse, hold the sides up with wooden skewers.
Lift the bag and water the soil every few days to maintain humidity and provide the moisture needed for root growth. Leave the pot in a bright and warm area away from direct sunlight. Root growth should develop in a couple of weeks, ready for transplanting outdoors or into individual containers.
Strobilanthes dyerianus don’t encounter many problems in the garden or indoors. Most issues relate to the natural growth habit of the plant, or incorrect planting placement.
Also keep an eye out for pests and diseases. They don’t often impact these plants, but if they do, the problem needs to be dealt with quickly before spreading to the rest of your garden.
If your Persian Shield doesn’t get enough sun or experiences heat stress, growth may become leggy. This can also occur over the seasons as the plant naturally grows and spreads out without regular pruning to keep the leafy growth compact.
To fix leggy growth, prune back the stems slightly to promote new growth and encourage branching. Don’t remove too much of the plant at once to prevent shock. A light trim back to the dense growth should improve the overall look of the plant.
Wilting is typically a sign of underwatering. Persian Shield loves moisture and will quickly wilt if the soil gets too dry. Luckily, a quick watering should perk the leaves up again and bring the plant back to life.
Adjust your watering schedule if wilting is frequent, watering more when temperatures are high to stop the soil from drying out completely.
If your plant is not placed in the right spot or in the right conditions, the leaves may begin to lose their color. Since they are grown primarily for their hue, this is a problem you’ll certainly want to avoid.
Dull foliage can be caused by excessive sunlight exposure, drops in temperature or heavy shade. The color of the leaves can also fade over time as the plant ages.
Ensure you plant in the right spot and protect from cold to improve coloration. If the discoloration is the result of age, trim a few stems to propagate and discard the rest of the plant.
Persian Shield doesn’t encounter many problems with pests or diseases. Aphids and whitefly are issues to watch for outdoors, while common indoor pests like spider mites and mealybugs can be a concern indoors.
Regularly check for problems and remove the bugs as soon as possible with targeted products to ensure they don’t spread to the rest of your garden.
Frequently Asked Questions
Can you plant Persian Shield from seed?
They can be grown from seed. However, seeds are difficult to purchase and hard to collect from existing plants due to limited flowering. It’s best to propagate from stem cuttings or purchase new starter plants from a nursery for the best results.
Is Persian Shield a perennial?
They can be grown as a perennial in USDA Zones 9 and above. In other regions it can be grown as an annual or grown indoors year-round to protect the tender foliage from cold temperatures.
Does Persian Shield flower?
This plant does produce small blue flowers, but doesn’t flower often when planted outdoors. They can flower indoors in winter under the right conditions. But the flowers don’t quite compare to the stunning hue of the leaves – the main attraction of this plant.
Will Persian Shield survive winter?
This plant is not cold tolerant and needs to be brought indoors or protected in a greenhouse in temperatures below 50F.
How tall does Persian Shield get?
These plants grow around 3 or 4 feet tall and 2 to 3 feet wide when given the space to expand.
Now that you’ve learned all you need to know about Persian Shield maintenance and care, the next step is to add one to your garden if you haven’t done so already. These unique looking plants have striking foliage, and will be the highlight of your garden, both indoors and outdoors. Provide proper care, and these beautiful plants will last you for many years to come.