Tuesday, February 27, 2024
Capers (Image: fedelacarrera1 Pixabay)
Plant Nutrition

Capparis – what am I eating?

By Clive Larkman

If you look up the word ‘Caper’ you will get a reference to a silly activity or dance-like movement, neither of which really points towards the tart little garnish we eat with cheese, pasta and whatever else we can imagine. However, the frivolity of the description does resonate with the randomness of the product. Capers, as we know them, are the un-ripened green flower buds of the plant, however there are also the ‘caper leaves’ and the ‘caper berries’ that are eaten around the world.

To start with, in Australia when we eat ‘capers’ we are eating the new buds of the plant Capparis spinosa. Some people produce a similar product from the immature buds of the nasturtium plant Tropaeolum majus. The main edible use of this plant is as a salad plant using both foliage and flowers. Capparis spinosa is a more varied plant in that the buds, flowers and in fact every part of the plant is edible. The buds are the most popular part but if these are left on the plant, the attractive flowers will form but only last a day. If pollinated they go on to produce the caperberry which is also edible.

All but the flowers are pickled prior to eating as they can be quite bitter in their raw state. The flowers are used mainly as a garnish. They can be hard to find as they open and close in a day, so harvest time (like the buds) is quite a narrow window. The capers and caperberries are quite easy to find in most supermarkets and delicatessens. The pickled leaves are harder to find and usually only sold in old fashioned independent delicatessens and specialist caper outlets.

Although a popular food, caper products are a gourmet or snack food. They are good for you and can help in a positive manner with many ills of the modern diet. As an aside, the foliage is quite acidic and is used as a vegetarian alternative in cheese making as a rennet replacement. The buds are harvested early in the morning and quickly processed. They are put aside for a day to wilt and then put into a heavily salted wine vinegar where they develop their characteristic flavour. Some food folks say the flavour is goat-like. This is one suggestion of where the generic name Capparis originates, i.e. the Latin word Capparis means billy-goat. The species name (spinosa) is the Latin word for spiny or prickly.

As discussed last month, Capparis spinosa is native to the Mediterranean islands and rim countries. It is native to almost all of them and is included in the flora of most of them, but whether it is indigenous to this region is uncertain. It is a shrubby plant that is many-branched, with thick, leathery, leaves, that are round to ovate. The flowers are very showy and sweetly fragrant with four white to pinkish-white petals and long violet stamens. The plants grow to about 1m high and can spread to an amazing 4m wide. This is because in nature, they are often found growing on cliffs, rock walls and other harsh places where their branches can hang down.

They like extremely well-drained soil and can take the hot dry Australian heat. They have low water requirements and, like most arid-tolerant plants, any supplemental water is good as long as they have good drainage. They are hardy to around -10oC and need at least six hours of summer sun each day to fruit and flower. They can tolerate all day sun if local conditions are right. While mature plants are drought tolerant the young ones need to be watered regularly until they become established with a good root system. An occasional summer feed with a balanced generic fertiliser will aid growth and health.

Capers and Australia

In Australia, the introduction and development of the Mediterranean caper plant started in the1990’s with a wholesale nursery (Cottage Herbs) propagating plants from seeds. There was no knowledge or experience of both propagating and growing capers in Australia. A Churchill scholarship was awarded and a trip to caper producers in Morocco, Italy and Spain improved the grower’s knowledge in this area. More information and photographs were collected later from Turkey, Greece, Malta, India, and Cyprus.

Cottage Herbs experimented with propagation techniques and trialled different growing environments.

There have been endless studies and investigations, by both private and governmental institutions all around the world, that concluded that for the caper industry to advance, two aspects were required. One was to select a good thornless variety and the second was to learn how to clone this variety for mass planting. Sadly, most of the first caper farms in Australia planted seed-grown bushes, which naturally have a strong propensity to vary, and produced both good and poor productive plants.

Brian Noone from Cottage Herbs, now under Caperplants Pty Ltd, conducted extensive trials over many years, with 100-200 stock plants. Measurements were recorded of harvest volume per plant every 10-12 days; the number of branches; the presence of side branches or not; when the plants started to regrow after the winter; and when the plants stopped growing as winter approached.

In Adelaide, South Australia there is a new variety, called ‘Eureka’, which is a variety of Capparis orientalis (syn Capparis spinosa subsp. rupestris). Its leaf shape is a variation of the species. Basically, its parent plants are similar to the thornless varieties grown in Southern Italy. The ‘Eureka’ (PBR) variety is easier for picking as it produces a row of capers on one branch, usually six to eight of them, with minimum development of side branches. It does not have thorns. It has a great flavour and produces a good harvest. It begins to shoot and grow earlier in the spring than other bushes, and continues to flower with the leaves staying greener longer into the autumn and winter.

In Australia the ‘Eureka’ caper plant has been tested and found free of the Eggplant Mottled Dwarf virus. The other two viruses that affect caper plants (Capl.v, and CMV) are non-existent in Australia. The horticultural business (Caperplants Pty Ltd) registered this ‘Eureka’ variety in 2009 with IP Australia under the Plant Breeder’s Rights (PBR) legislation. This is the only variety of caper plant registered with the International Union for the Protection of New Varieties of Plants (UPOV).

Caperplants successfully experimented for nearly 30 years, learning how to clone caper plants via vegetative means. A particular environment was created and a formulated propagation mix was developed that related to the chemistry of the plant. Now Caperplants have an international tissue culture partner and together they have mastered the art of propagation of the ‘Eureka’ variety by tissue culture.

These plants are now being trialled by a large nursery group in California and are exported to South Africa. These TC (tissue culture) grown plants are also available here in Australia see www.caperplants.com.

So, in Australia, we have been able to overcome the two stumbling blocks to the commercial caper industry and for home gardeners with the selection of a good variety, and a developed method to produce plants on a large scale.

Main photo: Capers (Image: fedelacarrera1 Pixabay)

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