Shiso Plant: Tasty Asian Mint Relative

The shiso plant is a staple herb in southeastern Asian countries. Shiso can be used in a variety of dishes from cold noodle dishes to hot ramen, from desserts to beverages. You can even bread it and fry it for delicious vegetable tempura.

Whether you eat a lot of Asian plants as food at home or not, shiso (also called perilla mint) is a good herb to grow in your garden. It has antioxidants, vitamin A, iron, and calcium, and can attract many pollinators to your garden with its beautiful flowers. The plant is heat tolerant and is only sort of picky when it comes to soil quality, making it a fairly easy plant for beginner gardeners to grow.

Shiso is also known as the beefsteak plant because its pink and red foliage is said to look like ground beef. It’s also called the rattlesnake weed in some areas because when this plant is allowed to self-seed, it can take over an area, just as other mint family plants can.

Let’s explore how to grow this delicious mint relative so you can start growing it at home!

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• Safer Brand Insect Killing Soap
• Monterey BT Caterpillar Killer (Bacillus thuringiensis)
• Neem Bliss 100% Cold Pressed Neem Oil
• PyGanic Botanical Insecticide
• Southern Ag Liquid Copper Fungicide

Quick Care Guide

All About Shiso

Shiso is scientifically known as Perilla frutescens and has several nicknames. The plant is in the mint family and looks like a large basil plant. It has a minty flavor, but it also tastes like cilantro, basil, and anise combined with cloves and cumin. It has a distinctive taste that you’re bound to fall in love with. 

Perilla frutescens is native to eastern Asian countries, so it’s so popular in Asian cuisine. Only the leaves are used in cooking since the stems have little hairs covering them. The plant has also been used in traditional medicine to treat a variety of health concerns, including anxiety, asthma, colds, the flu, headaches, and many more ailments.

The plant can grow 1-3 feet tall, and the leaves can grow up to 4 inches in length. Like other mint plants, it can spread quickly and take over an area if you don’t keep it trimmed. It has a distinctive minty aroma that you’ll smell as you handle the plant, making it enjoyable to work with.

The plant is ideal for growing in USDA zones 10-11, where it’s a perennial, but you can grow it in zones 2-9 annually if you keep it in a sunny area and protect it from cold temperatures. It will grow well as a container plant, so you can bring it indoors in the winter to keep it growing all year long.

Types Of Shiso

There are several varieties of shiso to choose from. They all have distinctive looks that will beautify your garden, so consider growing several of them!

• Red shiso: Red shiso is Perilla frutescens var. crispa and has a slightly different flavor than Perilla frutescens. Perilla frutescens var. crispa has a slight cinnamon flavor and has purple leaves with a flat surface. It’s used to color and season a dish called umeboshi, a type of pickled plums.
• Ruffled red shiso: Ruffled red shiso is similar to red shiso, but it has a ruffled surface instead of a flat one.
• Green shiso: Green shiso is the classic: flat surface and the expected minty basil flavor.
• Ruffled green shiso: Ruffled green shiso is the ruffled version of green shiso.
• Bicolor shiso: Bicolor shiso has a flat surface and is both red and green with green on top and red on the bottom.
• Variegated shiso: Variegated shiso is both red and green but can have both colors on each side.

Planting Shiso

The best time to plant shiso is spring. Start seeds indoors 8-12 weeks before the last frost date. Start seeds outdoors or plant transplants outside in spring once there’s no sign of frost and the temperatures stay above 45°F (7.2°C).

You can plant shiso almost anywhere if it’s sunny. It works well directly in the ground, in containers, and raised beds. Keep in mind that it’s considered invasive in many places, so if you don’t want to risk the plant taking over an area of your garden, a container may be best. Shiso grows best in full sun but can tolerate a little shade, so a sunny location with other plants will be suitable.

To plant the seeds, broadcast them in rows 1-2 feet apart. Or, sprinkle a few into a container. The seeds require light to grow, so it’s best to gently press them into the soil instead of covering them up. They should be no deeper than ¼ an inch. Keep the soil moist, and the seeds should germinate in about two weeks. Once they’re 3 inches tall, thin them out, so the plants are about 1 foot apart.

To plant seedlings, dig out a hole the same size as the root ball and fill any remaining space with soil. Keep the seedlings well-watered until they’re established. Shiso should have consistently moist soil, but they’re somewhat drought tolerant.

Care

Caring for shiso is pretty simple. Let’s take a look at everything you need to know.

Sun and Temperature

The ideal USDA zones for shiso are 10 and 11, but you can grow it as an annual in almost any zone. The temperature should be consistently above 45°F (7.2°C) when you plant shiso seeds or transplants.

Shiso can’t tolerate temperatures colder than 45°F, so you’ll need to bring it indoors over winter or grow it as an annual. Growing it in a container will allow you to bring it indoors during winter easily.

Water and Humidity

Shiso should always have moist but well-drained soil. You should never see puddles of standing water or dry soil.

You’ll need to provide your shiso with 1 inch of water per week. Rainwater is ideal, but supplementing it with the water hose is perfectly acceptable. Shiso is somewhat drought tolerant, so skipping a few days of watering shouldn’t be detrimental. However, it won’t grow as well during this time.

The best way to water shiso is to use soaker hoses so you can water the base and avoid getting leaves wet. Watering in the morning is best, so the water can have time to soak into the ground before the sun evaporates it. If you have to water overhead, do it very early in the morning so the plants can have time to dry off throughout the day to avoid diseases.

Soil

Shiso will perform best in soil that is mostly humus, loose, and full of organic matter. It won’t tolerate poor soils, but it can make do with average soil. Nutrient-rich soil will be best. Keep an eye on the pH of the soil as it grows best in 5.5-6.5.

Well-drained soil is essential because it prevents the plants from getting overwatered, so make sure the container has holes, or that the garden isn’t compacted.

Fertilizing

Since shiso plants aren’t heavy feeders, you shouldn’t have to fertilize more than three or four times per year. If you used lots of compost in the beginning and add it as needed throughout the year, you could probably avoid fertilizing altogether. If you do need to fertilize, choose an all-purpose fertilizer liquid or an all-purpose, slow-release granular fertilizer.

Pruning

Shiso doesn’t require much pruning. As it’s growing, you can pinch the stem tips above leaf nodes to promote bushy growth. If you harvest the leaves regularly, that should be all the pruning it needs. You may need to prune it if you’re not harvesting quickly enough, or if it’s allowed to grow a bit too big for its area.

Propagation

Shiso readily self-seeds and can take over the area. If you live in a warm enough area that it can grow as a perennial, you’ll have your current plant growing along with new seedlings from dropped seeds. It can get out of hand pretty quickly, so be sure to deadhead the flowers.

Typical propagation is only via seed. Unlike other mints, perilla does not produce runners.

Harvesting and Storing

And now, for the moment you’ve patiently waited for: harvesting! Harvesting shiso leaves are simple, and you can do it the entire growing season.

Harvesting

You can begin harvesting shiso leaves about two months after planting them and continue doing so for several months.

To harvest shiso, cut the stem above a pair of leaves. Use sharp, clean scissors so you don’t injure the plant or spread disease. Cut as much as you need, and the plant will continue to grow.

Storing

For short storage, place shiso in a sealable plastic bag with moist paper towels. It should last about four days.

For long-term storage, you can air dry or freeze-dry them by laying the leaves out on a cookie sheet for a few days, either in a warm place or in the freezer. You can also store them in a container in the fridge in layers with salt between each layer of leaves.

Troubleshooting

It’s generally problem-free to grow shiso, but there are a few things to look out for.

Growing Problems

Realistically, the only growing problem that you might have with your perilla mint is that it will literally grow everywhere. Just like other plants in the same family as mint, you’ll find growing shiso popping up in the areas where it produced seed the prior year. If you want to contain your purple perilla or ensure that you don’t have unexpected green shiso leaves appearing everywhere, consider container-growing shiso instead of putting it in the ground. Remove the flowers when they appear to reduce the likelihood of self-seeding.

Pests

There are a few pests that you may find around your shiso. Aphids can be black, green, red, yellow, brown, or grey, and they feed on the sap in the plant. You can use insecticidal soap, neem oil, or organic pesticides like pyrethrin to kill them, or you can attract ladybugs since they like to eat them. 

Cutworms feed on plant stems at the base of the soil and cut off the plant, and leafrollers are caterpillars that eat up leaves and use silk to roll up in and hang on leaves. Both of these can be prevented by protecting plants with row covers. You can use pesticides to get rid of them or use Bacillus thuringiensis (BT) as natural pest control.

Flea beetles, spider mites, and whiteflies are all small bugs that feed on plants. Spider mites inject toxins into the plants and flea beetles can spread diseases. Insecticidal soaps are a good way to get rid of these pests. Rotating crops with other plant families is a good way to prevent them.

Diseases

Shiso generally doesn’t have many diseases, but there are a few it might have occasionally. Bacterial wilt can be spread by flea beetles and will cause yellow streaking on the leaves. Damping-off and downy mildew are fungi caused by too much moisture. These diseases can be prevented with crop rotation and by watering at the base of the plant and avoiding the leaves. Diseased leaves or entire plants can be removed to prevent them from spreading.

Rust causes rust-colored spots on plants. Copper fungicide can be used to treat light outbreaks, but rotating the crops and removing the infected plants will help prevent the spread.

Frequently Asked Questions

Q: Is shiso an invasive plant?

A: Like other mints, shiso grows quickly and will easily self-seed. It’s considered invasive in some parts of the United States where people have allowed it to grow freely. However, you can easily control it in a garden.

Q: Is shiso a perennial?

A: Shiso grows as a perennial in USDA zones 10-11, but is an annual plant in zones 2-9. 

Q: Does shiso like full sun?

A: Shiso grows best in full sun, but it can tolerate partial shade.