Sea Rocket Information: How To Care For A Sea Rocket Plant

Sea Rocket Information: How To Care For A Sea Rocket Plant

By: Becca Badgett, Co-author of How to Grow an EMERGENCY Garden

Growing sea rocket (Cakile edentula) is easy if you’re in the right area. In fact, if you live in coastal areas, you may find the sea rocket plant growing wild. As a member of the mustard family, you might ask, “Is sea rocket edible?”.

Sea rocket information indicates that the plant is, indeed, edible and actually quite healthy and packed with nutrition. Sea rocket information is included in many foraging posts and guides online.

Is Sea Rocket Edible?

As a member of the crucifer or mustard family, the sea rocket plant is related to broccoli, cabbage, and Brussel sprouts. Sea rocket provides potassium, calcium, and a range of B vitamins, as well as beta-carotene and fiber. All plant parts are edible.

The sea rocket plant is large and spreading, with rocket-shaped seed pods, although the name comes from an old synonym for plants of the mustard family: rocket. During the winter, the leaves are leafy, but in the summer heat, the sea rocket plant takes on a strange, fleshy, almost alien-like form. It is also commonly called wild peppergrass and sea kale.

Sea Rocket Cultivation

The sea rocket plant grows and exists in the sandy soil closer to the ocean than the beach grass. Growing sea rocket actually prefers sandy conditions. As a succulent, the plant holds water, making growing sea rocket even easier.

When growing sea rocket, don’t include it as part of a vegetable garden. Companions for sea rocket cultivation must be of the same family (mustard). If the sea rocket plants detect roots of other type plants close to it, an “allelopathic” action occurs. The sea rocket plant releases a substance into the root zone that stunts or otherwise deters plants of other types. Grow it with kale and mustard family members for successful sea rocket growing.

Sea rocket puts a long taproot into the soil and does not like to be moved. Start it from the double jointed seed pods when they appear on the plant and mature, following the small purple blooms. This taproot makes the plant an excellent choice to hold and stabilize sandy soils that may be eroding.

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Plants Recognize Rivals and Fight, Play Nice with Siblings

Plants can't see or hear, but they can recognize their siblings, and now researchers have found out how: They use chemical signals secreted from their roots, according to a new study.

Back in 2007, Canadian researchers discovered that a common seashore plant, called a sea rocket, can recognize its siblings – plants grown from seeds from the same plant, or mother. They saw that when siblings are grown next to each other in the soil, they "play nice" and don't send out more roots to compete with one another.

But as soon as one of the plants is thrown in with strangers, it begins competing with them by rapidly growing more roots to take up the water and mineral nutrients in the soil.

Researchers from the University of Delaware wanted to find out how the plants were able to identify their kin.

"Plants have no visible sensory markers, and they can't run away from where they are planted," Harsh Bais, assistant professor of plant and soil sciences at the University of Delaware, said in a statement. "It then becomes a search for more complex patterns of recognition."

Bais and doctoral student Meredith Biedrzycki set up a study with wild populations of Arabidopsis thaliana, a small flowering plant that is often used as a model organism in plant research.

They wanted to use wild populations instead of laboratory-bred species, because the latter "always has cousins floating around in the lab," Bais said.

In a series of experiments, young seedlings were exposed to liquid containing the root secretions, called "exudates," from siblings, from strangers (non-siblings), or only their own exudates.

The length of the longest lateral root and of the hypocotyl, the first leaf-like structure that forms on the plant, were measured. A lateral root is a root that extends horizontally outward from the primary root, which grows downward.

Plants exposed to strangers had greater lateral root formation than the plants that were exposed to siblings.

Further, when sibling plants grow next to each other, their leaves will often touch and intertwine, while stranger plants near each other grow rigidly upright and avoid touching, the authors say.<< video="LS_091015_plant-siblings" title="Plants Know Their Siblings" caption="Plants use chemical cues to recognize and cooperate with siblings, while spurring competition among rivals. Credit: University of Delaware." >>

In future studies, Bais hopes to examine questions such as: How might sibling plants grown in large monocultures, like corn, be affected? Are they more susceptible to pathogens? And how do they survive without competing?

"It's possible that when kin are grown together, they may balance their nutrient uptake and not be greedy," Bais speculates.

The research also may have implications for the home gardener.

"Often we'll put plants in the ground next to each other and when they don't do well, we blame the local garden center where we bought them, or we attribute their failure to a pathogen," Bais said. "But maybe there's more to it than that."

The study, funded in part by the National Science Foundation, will be published in the January/February 2010 issue of the journal Communicative & Integrative Biology.

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It is a glabrous, succulent annual, with a slender or stout taproot. It has a branched stem prostrate or ascending, growing up to 15–45 cm (5.9–17.7 in). The lobed leaves, [2] are flesh-like and alternate (spaced), they are different from top and bottom of the stem, the lower leaves are obovate or oblancelate, while the upper ones are oblong. [3] It blooms in the UK, between June and August. [2] The small flowers come in shades of white, lilac-coloured or purple, [3] [2] with 4 petals measuring up to 25 mm (0.98 in) across. Later it produces green maturing to brown, seed capsules (fruit), that are short and stubby. They contain 2 yellow, brown, smooth seeds. [3] [2] The seed oil contains a high level of erucic acid. [4] [5]

Due to its highly efficient antioxidant system, [6] it can withstand even high doses of Cadmium pollution. [7]

It was published and described by Giovanni Antonio Scopoli in 'Fl. Carniol.' edition 2, Vol.2 on page 35, in 1772. [8] [9]

The specific epithet maritima, refers to the Latin term for 'of the sea'. [10]

  • Cakile maritima subsp. baltica (Rouy & Foucaud) Hyl. ex P.W.Ball (synonym: Cakile baltica Jord. ex Pobed.) [11]

Cakile maritima is native to temperate areas of North Africa, western Asia and Europe. [12]

Range Edit

It is found in Africa within Algeria, the Canary Islands, Egypt, Libya, the Madeira Islands, Morocco and Tunisia. In Western Asia, it is found in the Caucasus, Georgia, Iran, Israel, Syria and Turkey. In Eastern Europe, it is found in Estonia and Ukraine. In middle Europe, it is found within Belgium, Germany, the Netherlands and Poland. In Northern Europe, in Denmark, Finland, Iceland, Norway and the United Kingdom. In Southeastern Europe, within Albania, Bulgaria, Croatia, Greece, Italy, Montenegro, Romania, Serbia and Slovenia. In Southwestern Europe, within France, Portugal and Spain. [12] It is also widely naturalised outside of its native range, in North America. [12]

Habitat Edit

It grows on the foreshores near large dune systems, [3] and in shingle banks. [2] It is tolerant of salt spray and transient seawater inundation. It is pollinated by a wide range of insects, from Apis mellifera, Eristalis intricarius and Pieris rapae. [3]

As the seed oil contains a high level of erucic acid it can have pathological effects on the cardiac muscle of several animal species. However, orange-bellied parrots feed on its seed during their northward migrating journey from Tasmania and Australia. [3]

The leaves are edible, preferably cooked, and not eaten in great quantity. [13] The seed oil can be used for industrial applications. [5]


a flight vehicle propelled through space by the reactive thrust that occurs when the rocket ejects a portion of its own mass (the working fluid).

A typical rocket includes the following subassemblies: one or more rocket engines, a source of primary energy, a store of working fluid, and a payload. No ambient medium is needed for rocket flight this factor renders the rocket the only suitable vehicle for space flights. The basic energy and operating characteristics of a rocket depend on the type of rocket engine and the type of fuel. Practically all modern rockets have engines that operate on a chemical fuel. The thrust developed by the rocket engine and the exhaust velocity of the reactive jet are of primary importance in a rocket the thrust of the rocket engines used to launch spacecraft can reach 10 meganewtons, and the exhaust velocity of the reactive jet is between 3,000 and 4,500 m/sec.

Rockets are used for military purposes and scientific research and also for launching spacecraft. They may be unguided, as in some types of antitank, antiaircraft, and aircraft missiles, or guided. Guided missiles are equipped with devices that force the missile to alter its motion during flight. Guided ballistic rockets include rockets that use their own flight momentum over a major portion of their trajectories after shutting off the engine for example, within the earth’s gravitational field a rocket moves along a curve that is part of an ellipse and is called a ballistic curve (seeBALLISTICS).

Depending on their major structural features, rockets may be classified as single-stage or multistage rockets. A modern single-stage rocket usually consists of a nose section, an instrument section, a fuel section, and an engine section. The nose section contains the payload (in military rockets this is an explosive charge), and the instrument section contains the guidance systems and other instruments. In contradistinction to liquid-propellant rockets, solid-propellant rockets feature integrated fuel and engine sections, because the entire fuel supply is housed within the engine chamber.

Othonna cakilefolia

Common names: sea-rocket othonna (Eng.) bobbejaankool (Afr.)


One of only three Othonna species with pink to magenta florets its striking, pink daisy-like flower heads, make it a desirable member of the genus.

Fig. 1. Habit of Othonna cakilefolia showing trisect to pinnatisect leaves with narrow, obtuse lobes and pink daisy-like flower heads. (Photo Nick Helme)



Othonna cakilefolia is a herbaceous geophyte, up to 500 mm high, arising from a short, thick, tuberous root. The annual stems bear leathery to sub-succulent, ovate to elliptic, rarely linear, trisect to pinnatisect leaves.

Fig. 2. The trisect to pinnatisect leaves of Othonna cakilefolia. (Photo Adam Harrower)

Flower-heads are solitary or in clusters of 3, sometimes with lateral axes, radiate ray florets magenta or pink, sometimes darker basally disc florets magenta involucral bracts 10 or 12.

Fig. 3. Othonna cakilefolia capitula with magenta disc florets and pink to magenta ray florets. (Photo Nick Helme)

Fruits with stiff short hairs on the ribs that release mucilage when wetted and a pappus of beige, barbellate bristles that aids in dispersal (Magoswana et al. 2016, 2019).

Fig. 4. Othonna cakilefolia fruits with stiff short hairs on the ribs and barbellate bristles. (Photo Nick Helme)

Conservation Status


Othonna cakilefolia is currently assessed as Vulnerable (VU) in the Red List of South African plants (Raimondo 2007). However, the species has recently been recorded by botanist Nick Helme (pers. communication June 2019) as quite common but seemingly very local on loamy shales.

Distribution and habitat

Distribution description

Othonna cakilefolia is a poorly collected species known from a few localities between Kamieskroon and Holrivier, with an isolated collection near Lutzville along the west coast, on sandy flats or quartz outcrops below 500 m (Rowley 1994, Magoswana et al. 2019).

Fig. 5. The tuberous root of Othonna cakilefolia. (Photo Nick Helme)

Derivation of name and historical aspects


The genus name Othonna is probably from the Greek word, othonne, for linen or cloth, referring to the soft leaves of some species (Jackson 1990). This species was named by De Candolle, in 1838, for the resemblance of its leaves to those of the genus Cakile, commonly called sea rocket (Rowley 1979).

The genus Othonna L. comprises ± 90 species excluding the recently segregated genus Crassothonna B.Nord. (Leistner 2001, Nordenstam 2007, 2012, Manning & Goldblatt 2012, Glavich 2016, Magoswana et al. 2019). Species of Othonna are succulent or sub-succulent perennial herbs or shrubs with more or less dorsiventrally flattened leaves, radiate or disciform capitula with female-sterile disc florets and female marginal florets, with a beige or reddish pappus that is sometimes accrescent (Leistner 2001, Manning & Goldblatt 2012, Nordenstam 2012, Glavich 2016, Magoswana et al. 2016, 2019). The genus is recognized by the presence of undivided (or minutely bifid) styles in disc florets (Nordenstam 2012, Magoswana et al. 2019).

Othonna cakilefolia, O. lilacina and O. rosea are the only species in the genus with pink to magenta ray florets. They are distinguished by leaf shape and number of involucral bracts. O. cakilefolia with trisect to pinnatisect leaves, with narrow, obtuse lobes, and 10 to 12 involucral bracts. In the last-named 2 species, the leaves are entire or variously toothed to pinnatisect (Manning & Goldblatt 2010, Magoswana et al. 2019).



Othonna cakilefolia grows on small outcrops of white quartz or sandy soils and loamy shales, flowering in winter and spring, from June to September. The inflorescence dies off during the dormant season. Flowers are bee and insect pollinated.

None recorded. However, it has horticultural potential.

Growing Othonna cakilefolia

Othonna cakilefolia is a challenge to cultivate, is rarely seen in cultivation and propagative material is not often available. Seed should be sown in autumn in a well-drained, sandy loam soil mix suitable for succulent plants and covered lightly to hold them in place. Keep the soil moist but not wet, and place them in a warm, sheltered position. Seeds should germinate in about 2 weeks (Harris 2014, Sutty 2017). Seedlings produce 2 fleshy cotyledons and nothing further until, after a long period when the cotyledons may or may not have withered away, new growth, with true leaves, appears from a lateral bud on the tuberous stem (Rowley 1979). Transplant with care because the plants break easily, into a pot that is deep enough to accommodate its tuberous root. Use a similar soil mix, with bonemeal as a fertilizer. Grow them in a sunny position, with moderate water in autumn, winter and spring and a completely dry summer. It could be grown in a sunny rockery in water-wise gardens in low rainfall, winter-rainfall areas, but in other areas it is better suited to containers and placed in a sunny, well-ventilated position.


  • Glavich, T. 2016. Beginner’s guide to geophytic Othonna. Cactus and Succulent Journal 88: 89–91.
  • Harris, S. 2014. Othonna retrofracta (L.) Jacq. (Asteraceae). PlantZAfrica. Online.
  • Jackson, W.P.U. 1990. Origins and meanings of names of South African plant genera. University of Cape Town.
  • Leistner, O.A. (ed.). 2000. Seed plants of southern Africa: families and genera. Strelitzia 10. National Botanical Institute, Pretoria.
  • Magoswana, S.L., Boatwright, J.S., Magee, A.R. & Manning, J.C. 2016. A taxonomic revision of Gymnodiscus (Asteraceae: Senecioneae: Othonninae), a Greater Cape Floristic Region endemic. South African Journal of Botany 106: 71–77.
  • Magoswana, S.L., Boatwright, J.S., Magee, A.R. & Manning, J.C. 2019. A taxonomic revision of the Othonna bulbosa group (Asteraceae: Senecioneae: Othonninae). Annals of the Missouri Botanical Garden 104(4): 525.
  • Manning, J.C. & Goldblatt, P. 2010. New synonyms and a new name in Asteraceae: Senecioneae from the southern African winter rainfall region. Bothalia 40 (1): 37–46.
  • Manning, J. & Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: the Core Cape Flora. Strelitzia 29. South African National Biodiversity Institute, Pretoria.
  • Nordenstam, B. 2007. Tribe Senecioneae. In J.W. Kadereit & C. Jeffrey, Kubitzki’s The families and genera of vascular plants Vol. 8. Springer, Heidelberg, pp. 208–24.
  • Nordenstam, B. 2012. Crassothonna B. Nord., a new African genus of succulent Compositae-Senecionae. Compositae Newsletter 20, 70–77.
  • Raimondo, D. 2007. Othonna cakilefolia D.C. National Assessment: Red list of South African plants version 2017.1. Accessed on 2020/02/04.
  • Rowley, G. 1979. Othonna cakilefolia DC. The Cactus and Succulent Journal of Great Britain 41(2): 34.
  • Rowley, G.D. 1994. Succulent compositae. A grower’s guide to the succulent species of Senecio & Othonna. Strawberry Press, California.
  • Sutty, C. 2017. Othonna herrei Pillans (Asteraceae). PlantZAfrica. Online.


Xichavo Mathebula and Luvo Magoswana
Compton Herbarium
May 2020

Acknowledgements: the authors thank Nick Helme and Adam Harrower for providing the images to illustrate this article.

Plant Attributes:

SA Distribution: Northern Cape, Western Cape

Flowering season: Spring, Winter

Flower colour: Purple, Pink, Yellow

Aspect: Full Sun, Morning Sun (Semi Shade), Afternoon Sun (Semi Shade)

Leymus arenarius (Lyme grass) will reach a height of 1.5m and a spread of 0.5m after 2-5 years.

Suggested uses

Beds and borders, City, Coastal, Cottage/Informal, Drought Tolerant, Flower Arranging, Foliage only, Ground Cover


Grow in well-drained soil in a sunny position. An easy plant to grow, tolerating poor soil, drought and coastal conditions. Site carefully, as this plant can be invasive.

Soil type

Chalky, Clay, Loamy, Sandy (will tolerate most soil types)

Watch the video: Sea Rocket