Capparis spinosa Seeds | Caper
LATIN NAME: Capparis spinosa
COMMON NAME: Caper, Wall Caper
Plant Profile
The plant is a low, sprawling shrub with a woody base and long trailing stems that die back in cold winters and resprout from the crown. Leaves are rounded, leathery and slightly blue-green, and the flowers are large and conspicuous, with four white to pinkish petals and a burst of long stamens that carry the ovary out on a stalk. That stalk, the gynophore, is what elongates into the fruit — a capsule that splits to release kidney-shaped seeds in a red pulp.
Each leaf carries a pair of stipular spines, curved like small hooks, which is where the epithet spinosa comes from and why picking is done with gloves. The spines also tell the two common forms apart: the cultivated variant selected for easy harvest is largely spineless, while the wild, spine-bearing form is the one that survives grazing.
The immature fruit, picked before it splits and cured the same way, is the caperberry: larger, milder and served as a garnish in its own right. Salt-packed capers must be rinsed before use; brine-packed ones need only draining. They belong with oily fish, tomatoes and olives, where the acidity cuts fat.
Science & Biotechnology
The buds are a concentrated source of the flavonol glycoside rutin, alongside quercetin and kaempferol derivatives and a useful amount of ascorbic acid. Rutin is the compound behind the plant’s place in cosmetic formulations for fragile capillaries.
Fresh buds are inedible and oxidise within hours, so handling is a race, and every traditional method acidifies or salts the tissue fast enough to stop the enzymes.
Uses & Benefits
Caper pungency comes from the same chemical family that gives mustard and horseradish their bite. The buds store glucocapparin, a methyl glucosinolate, together with related glucosinolates; when tissue is crushed, an enzyme releases the aglycone, which rearranges into methyl isothiocyanate. That volatile is the sharp note in a good caper, and it is volatile enough that long cooking drives it off, which is why capers go into a dish near the end.
Growing from Seed
Caper grows where little else will: skeletal, calcareous soils, old walls, saline ground near the coast. The root system descends far below the shallow profile of such sites, which is the reason the plant survives a dry Mediterranean summer without irrigation and resents a wet, rich garden bed. Frost is the real limit — the top growth is killed at a few degrees below freezing, though the crown usually returns.
Caper is grown commercially from cuttings as much as from seed, because seedlings vary in spininess, bud size and yield. Tissue culture work has concentrated on shoot multiplication from nodal explants and on rooting, offering a way to multiply a chosen clone quickly.
Plant caper where the soil is poor, limy and sharply drained, in full sun and against a wall or bank that sheds water. Rich soil and summer irrigation produce a leafy shrub with few buds.
Caper seed carries a hard, impermeable coat and will sit in the ground for a long time if sown dry. Rub the seed between sheets of sandpaper or nick the coat, then soak it in warm water before sowing into a gritty mix, barely covered; keep the tray warm and only lightly moist. Seedlings are slow and should be grown on in deep pots, because the taproot resents disturbance at transplanting.
Established plants are cut back hard in late winter to force fresh, productive growth and to keep the bush within reach; the oldest stems are removed entirely to renew the frame. Feed lightly in spring, and never mulch with rich compost. Pests are few: root rot in wet ground is the main killer, and the crop is otherwise left alone.
Our Take
If the genus interests you more than the brine jar, the eastern highland plants sold as Himalayan caper are the hardiest of the group, while Masaikai caper is grown not for buds but for mabinlin, the sweet-tasting protein in its seed. On the same dry, limy ground, Munstead lavender asks for exactly the drainage this shrub demands.
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