Capers are native to the Mediterranean area, as well as to the tropics. The name caper derives from the Arabic word Kabar. The plant is a deciduous dicot. It grows about two feet tall and spreading (Figure 1). The vines can be 7 to 10 feet long (2-3 meters) The plant has a very deep root system.

The flowers are bisexual with numerous stamens. They are attractive and resemble a rose flower, with white petals and purple shades about 2 to 2.5 inches in diameter (4-6 cm ). The lifespan of the flower is short, about 24-36 hours- but each plant produces hundreds each season.

The elongated, green fruit (Figure 2) is 2-3 inches long (3-5 cm ), 1/2 - 3/4 inch in diameter (1-1.5 cm), and contains 200-300 seeds (Figure 3). The leaves are oval in shape, leathery and shiny green.

The smaller the bud the higher the quality and price. A glass vial of about 7 ounces (200 grams) of good quality capers sell for almost $5.00. The fruit is also brined but is considered of inferior quality, and is not as important commercially.

Caper buds are classified in six categories (depending on their size), processed and then packed in jars of various sizes.

Grade Diameter of buds

Nonpareilles 7 mm or less

Surfines 7-8 mm

Capucines 8-9 mm

Cappotes 9-10 mm

Fines 10-10.5 mm

Current Production. Capers are grown commercially in Morocco, Spain and Italy. In Greece, Cyprus, and Turkey the plant is well adapted but it is not cultivated commercially. The United States imports more than $10 million worth of processed and non-processed capers annually from these countries.

Besides these food uses, capers can be used as an ornamental — the flowers are numerous and very attractive and the foliage is shiny, deep green. Finally, the plant may be used to control soil erosion, especially on slopes where irrigation is difficult and soil erosion is more pronounced.

Propagation and Care. The plant is very drought resistant, needs little cultural care, requires good drainage, and has few disease and insect problems.

The plant is propagated by seed or by cuttings or roots. The preferred methods of propagation are root or cuttings simply because of the variability found in seed propagated plants (Figure 9).

The cuttings are rooted in the greenhouse for at least one year and then planted in the field, spaced about 16 by 16 feet apart (5 by 5 meters). Field planting takes place during February-March. During the first two summers after planting 2-3 irrigations are required but plants older than 2 years can survive with little irrigation. Spring fertilization with Ammonium sulfate (21-0-0) or 16-16-16 at a rate of 1/2 pound per mature plant per year is advisable. Watering is required after each application.

Germinating and Transplanting Seedlings. Caper seed is difficult to germinate. The method described here has resulted in 40-75% germination. Seedlings are very temperamental when transplanted. Some may wilt and die. To reduce this loss, transplant with soil attached to the root system, water and cover with a plastic bag immediately after transplanting. Use mature (dark brown-black) seed, one to two years old.

Put seed in warm water (108-110° F.) to soak for at least 12 hours. Let water cool to room temperature. No need to keep the water temperature at 108-110° F. for the duration of this treatment. Discard water, wrap seed in a moist towel, place in a plastic bag and keep in the refrigerator for 50 to 65 days. Then take seed out of the refrigerator and treat it again in 108-110° F water. No refrigeration is necessary this time.

Plant the seed about 1/4 to 1/2 inch deep in a soil mix of 50-25-25 parts planting soil, perlite and sand, respectively or UC soil mix. Use 6 inch clay pots or deep flats. Water well and keep in a warm area (70-85° F.), in part to full sun. Do not let top of soil crust over. Keep soil moist. Germination should start within 3-4 weeks and may continue for 2-3 months. Not all seeds germinate at the same time.

Let seedlings grow to 3-5 inches tall before transplanting. If seedlings are too crowded in the clay pot or flat do not pull them. Instead, use a scissor and cut off the small, less vigorous, undesirable ones. This way the root system of the remaining seedlings is not disturbed.

Transplant the seedlings to individual one gallon containers, in the same planting mix as above. When transplanting, disturb the root system as little as possible — try to keep some original soil around each transplanted seedling. Good soil drainage is essential to prevent root rot. Pack the soil tight around the transplanted seedling and water immediately. Cover each container with a plastic bag and keep in a shaded spot (if it is spring, summer) or in a warm area (70-85° F.) if it is winter. Keep the plastic bag in place for 4-5 days. Then cut off the top of the bag so that the seedling will be gradually exposed to the natural environment. In another 10 days enlarge the plastic bag opening. One week later remove the plastic bags and keep in a shaded area. Keep in the one gallon containers and plant in early spring, after the last frost, when soil is workable.

Diseases. Graymold, Botrytis sp. infected young buds of plants grown in moist shaded spots and of plants which were frequently sprinkle-irrigated at the U.C. Botanical Garden, at Berkeley.

The fungus Pythium sp. was isolated from caper plants grown in an experimental plot. The roots were infested with the Rootknot nematode. Some plants growing in the greenhouse developed oedema (edema, from the Greek = swelling). This is a physiological disorder which may impair regular leaf funciton and growth.

Nematodes. Caper roots imported from Spain were planted in a farm in Brentwood, CA. A year later they were found to be heavily infested with the root nematode, Meloidogyne sp.

Insect Pests. The imported cabbageworm, Pieris rapae, the black vine weevil, Brachyrhinus (Otiorhynchus) sulcatus, and the flea beetle, Phylloptera sp. have caused foliage damage in caper plants in California. Gophers, snails and slugs can also attack capers causing root of leaf destruction.

Young caper plants in containers were attacked by larvae of the Imported Cabbageworm or Cabbage Butterfly (Pieris rapae). The larvae devoured large portions of the leaves. It is one of the most serious agricultural insect pests.

This insect damages the outer leaves of cabbage, cauliflower, mustard, turnip, sweet alyssum, lettuce, nasturtium and many weeds causing large irregular holes in the leaves. The infested plants become stunted and leafy vegetables are not marketable.

The larva is about 1 1/4 inches long and velvety, deep green in color.

Early in the spring the white butterflies appear. Each female deposits several hundred eggs on the underside of the leaves of host plants. The eggs hatch in a week or so. The insect overwinters as pupae. There are 3 to 6 generations per year.

The larvae can be controlled with insecticides as well as with preparations of Bacillus thurigiensis (Thuricide, Dipel).

The leaves and the fruit of several caper plants in the author's experimental plots in Pleasant Hill and Brentwood were severely damaged by a small jumping beetle. The California Dept. of Food & Agriculture identified it as, Phyllopreta sp. a flea beetle of the Chrysomelidae family.

The leaves and fruit were stippled (speckled), almost bleached. Plants which were next to a strawberry patch (Pleasnt Hill plot) were severely attacked, whereas, those further away from the strawberries were free of damage.

There are two caper cultivars in the Pleasant Hill plot -- the spiny and the spineless. Both were attacked but the spiny cultivar was damaged more than the spineless.

The beetle population diminished by the end of August and by September 8, no beetles were found on the plants.

Harvest and Postharvest. Mature caper plants are pruned to ground level during November-December. In the spring, tender new shoots develop, which are used as a vegetable and, according to some people, taste better than asparagus spears. Buds are picked from mid-May to the end of August. A 2-year old plant will produce some, a 3-year old plant produces about 2 lbs/year, and a plant older than 4 years may produce over 20 lbs. of buds per year. The unopened buds are picked by hand, sorted into five different qualities, and cured and packed as described below.

1. Sort caper buds into small, medium and large sizes.

2. Place buds of each size into a strong salt brine (salt-water solution) of 1 1/4 to 1 1/2 lbs. of salt per gallon of water. If a salt hydrometer or salometer is used to determine the concentration, they should measure 15 to 18% or 60 to 72 degrees S.

3. Keep the caper buds in the brine for 30 to 45 days. They can be kept in this brine up to 12 months without damage. Make sure capers are kept submerged in the brine.

4. Remove capers from brine and rinse in running water for several minutes to remove excess salt.

5. Pak capers into small jars up to the shoulders of the jars. Cover the capers with an acidified solution of 1 gallon of 5% vinegar in 2 1/2 gallons of water and 1 1/2 teaspoons salt. Leave 1/4 to 1/2 inch headspace between the top of the liquid and the rim of the jar. Adjust lids and screw down hand tight. Do not over-tighten the lids.

6. Jars of capers in acidified brine can be kept in the refrigerator for up to 6 months, or:

Jars of capers can be pasteurized by submerging them in a hot water bath of 170 to 175° F. When the temperature of the water bath retuns to 170° F, set timer for 30 minutes. Remove from hot water bath and allow to air cool. Shelf life of pasteurized capers is about 1 1/2 years at room temperature.

Figure 1. Caper plant (photo by D. Kontaxis).

Figure 2. The caper fruit is 2 to 3 inches long and about 1/2 inch in diameter (photo by D. Kontaxis).

Figure 3. Each fruit contains 200 to 300 caper seeds (photo by D. Kontaxis).

Figure 4. The unopened buds are sorted by size and placed in a brine solution (photo by D. Kontaxis).

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