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Perilla - an Asian culinary herb

John Follett: FollettJ@crop.cri.nz
Ruakura Agricultural Research Centre
John Burgmans, John Scheffer
A printed copy with photos is available. Updated: Mar. 1996

Introduction

Perilla (Perilla frutescens), a member of the family Labiatae, is an annual herbaceous plant native to Asia. It features extensively in Japanese cuisine where it has a variety of uses. There are two main types: red perilla and green leaf perilla or oba. Both types are commonly called shiso. Red perilla is used as a dye for pickling fruit and vegetables, as a dried powder to be used as a side dish with rice, as an ingredient in cake mixes and as a flavouring in beverages. It is generally harvested and sold as a bulk commodity directly to the processing industry. 

Red perilla flower heads are also used as a condiment with sushimi, and three to six-week-old seedlings or sprouts are used as a garnish. Green leaf perilla, the product most commonly seen in Japanese markets, is used as a vegetable. Its leaves are used as a wrapping for rice cake, in salads and tempura. Perilla is also grown for its seed which can be used for oil production and to flavour foods, especially pickles. Other market opportunities include oil production from the foliage, and production for medicinal use (perilla has bactericidal properties). 

Climate and soil

Perilla requires an equitable climate to grow well; it is unsuitable for areas that experience out-of-season frosts. Warm temperatures, long day length and adequate moisture are required for good vegetative growth, and short days for flower production. Most soils considered suitable for horticulture will support perilla. Sandy soils rich in organic matter are considered optimum. Fertiliser application depends on residual soil fertility levels and soil type. Annual dressings of an NPK fertiliser would, in most cases, be prudent. 

Propagation

Perilla is an annual plant propagated by seed. Plants flower and seed in late summer-autumn with the seed germinating readily if sown in the following spring. The optimum germination temperature range is 20°C-22°C. Cool temperatures or dry conditions during germination are likely to have a detrimental effect on germination and seedling emergence. 

Agronomy

The most common production method in Japan for green leaf perilla is under cover in glass or plastic houses. Leaf production occurs during long days with perilla quickly running to seed when short days commence in autumn. With artificial heating, lighting, irrigation and successive planting it is possible to produce perilla continuously. A less expensive production method is semi-protected planting. Seedlings are grown in heated beds in a plastic house in late winter, transplanted in spring and harvested during summer. Using this method, plants are protected from wind and rain when growing conditions are marginal. However, without artificial lighting, plants quickly bolt to flower and seed in autumn. The least expensive production method involves seedling production in unheated beds in early spring followed by transplanting in late spring. Harvesting is carried out during the summer months. Once the plants are 30 cm high, leaves that are 10 cm long (excluding the petiole) are plucked from the stem. Bundles of 10 leaves are tied with a rubber band and packaged ready for market. Harvesting, which is labour-intensive and a major cost to the grower, should be carried out at least once every two days and more often if plants are growing rapidly. 

Red perilla

Red perilla, which is not usually produced out of season, is grown as a bulk commodity and used in Japan mainly by the processing industry. It is sown, in spring, directly into raised beds that have first been fertilised and cultivated. Five to six seeds are sown per station in 80 cm wide raised beds. Seeds are not thinned with four plants per station at harvest considered optimum. Seeds are sown every 12 cm in rows 40 cm apart. A black plastic mulch is often used to keep the crop weed-free. In early summer, when plants are about 40 cm high, the top 10 cm are machine harvested. This harvesting procedure is repeated as often as required until autumn when the crop starts to flower. 

Perilla sprouts

Perilla sprouts are used as a garnish by restaurants and hotels. They are produced in the open during summer and under cover in heated beds in winter. Prior to sowing, base fertiliser is applied and worked into the soil. The ground is then worked up into raised beds and the surface raked to produce a fine tilth. Seeds are broadcast sown. Soil or sand is then sieved over the seed until they are just covered. The beds are then watered and covered with straw. After the shoots have started to appear the mats are removed. Once the seedling leaves have fully opened and the first true leaves have started to form the seedlings are cut with scissors, washed and packaged into small wooden boxes ready for market. 

Perilla flower

Perilla flower heads are also used as a condiment and are required by the Japanese restaurant and hotel industry all year round. This demand is satisfied using a range of cultivars and growing under cover during winter. Seedlings are raised in a nursery and when they have developed five to six true leaves they are transplanted into beds. Seedlings are planted in rows 90-120 cm apart. Within-row spacing depends on the time of the year. Early cultivars flower earlier and, therefore, require less space. If produced during the off season the crop is covered in a plastic tunnel to maintain the temperature at 15°C. Liquid fertiliser is sometimes applied depending on the rate of growth. For market, flower stalks are cut 15 cm from the tip when five to six of the flowers have opened. During grading the stalks are cut to a length of 8-10 cm before packaging ready for market. 

Cultivars

A wide range of perilla cultivars are grown; the choice depends on the intended use of the product. The main cultivars for oba production are Ao-oba (green large leaf), Ao-jiso (green) and Ao-chiri-men-jiso (green cotton crepe), but most growers develop their own lines by continually selecting seed from their best plants. When selecting plants for oba production the following are considered desirable characteristics: bright green, broad, oval-shaped leaves; leaves with deep serrated edges; a strong aroma; creped leaf surfaces; vigorous growth; tendancy to produce many side shoots; and reluctance to bolt in autumn. 

Pests and diseases

Cutworm, mites, aphids and leaf-eating caterpillars are all pests of perilla. A range of chemicals can be used to control these pests, but withholding periods after chemical application must be strictly enforced. Reports from Japan suggest that fungi including damping off, downy mildew and rust, may also cause problems. In New Zealand, browsing caterpillars and white fly have been the main problem. 

Production in New Zealand - market potential

Trials in the Waikato, Hawke's Bay and South Auckland areas have demonstrated that perilla (red and green leaf varieties) can grow well in New Zealand although the Waikato can be marginal because of out-of-season frosts. In the Hawke's Bay region perilla at 12 000 plants/ha yielded up to 65 kg/ha leaf dry weight. Some interest has been shown in producing fresh perilla leaf in New Zealand for the Japanese market, however, high labour costs and short shelf-life suggest that this commercial opportunity is unlikely to be realised in the short term. It is more likely that perilla from New Zealand will be exported in a processed form. 

Seed sources

Seed for both red and green varieties can be obtained from Kings Seeds Ltd, 

Printed copies of this page

This page is available in printed form with b&w photos at a cost of:
New Zealand - NZ$2.00;
Australia - A$2.00; 
Everywhere else US$2.00 
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While every care has been taken when preparing this document, no liability will be accepted by the New Zealand Institute for Crop & Food Research Limited for any loss or damage suffered as a result of applying the information contained in this document. Copyright © 1999 The New Zealand Institute for Crop & Food Research Limited, Private Bag 4704, Christchurch, New Zealand.