The caper bush (Capparis spinosa) is best known for the flower buds that are picked and used in cooking. The berries the plant produces are also pickled and used in cooking. So are the young shoots and leaves. The caper bush is originally from Southern Europe and Asia. It is a spiny, broad leaf evergreen shrub that grows up to five feet tall and spreads six feet. Leaves are green and somewhat oval. The flowers are large, white tinged with red or lilac. They are two to three inches across with large, projecting, purple, stamens. The flowers are fairly short lived. The caper bush blooms from late spring to late summer. The caper bush grows in zones nine to eleven. It can be grown as a pot plant in other zones and be brought in for the winter.
Caper bushes require full sun to grow well. They are intolerant of shade. Caper bushes are used to living in marginal soil conditions. Rather than preparing a soil rich in organic matter for this plant, you prepare a place with sand and chips of rock for it to grow in. If you are growing the caper bush in a pot, fill it with well drained sandy loam. Established caper bushes require very little water and detest wet feet, so make sure the soil where they are planted drains well.
Caper bushes are tolerant of rabbits, deer, and drought. They are excellent to place in rock gardens and marginal places no other plant will grow in.
Capers may be propagated by seed, although finding a source of seeds is a challenge. The seeds are small. They should be soaked overnight in warm water, then wrapped in a towel and stored in the refrigerator for two to three months.
When removed from the refrigerator, they should be re-soaked overnight and then planted to a depth of one centimeter. Many of the seeds do not germinate, even with this treatment.
Caper bushes can also be propagated by cuttings. Collect cuttings in February, March or April using basal portions with six to 10 buds. Dip the cuttings in rooting hormone and then stick them in loose, well draining soil with a heat source at the bottom.
The capers, or flower buds, are harvested and divided into five distinct groups. The buds are picked when immature, before they open. The size categories are as follows: nonpareils, capuchins, capotes, seconds, and thirds. The nonpareils are the most prized and the most expensive. It is difficult to harvest the capers because of the thorns and spines on the leaves. The smaller the bud, the more difficult to reach it in amongst the thorns and spines, hence the greater expense.
Caper bushes do not need to be fertilized as they are used to growing in poor soil. Caution should be used when planting caper bushes. Make sure pets and children will not have access to the plant so the thorns and spines will not injure them.