Diplotaxis is from the Greek diplos meaning double and taxis meaning row referring to the double row of seeds in the pod.
Tenuifolia is from the Latin tenuis meaning slender and folium meaning leaf and referring to the slender leaves.
Sand Rocket because it prefers sandy soils and rocket is a common name applied to several plants in the Brassicaceae family.
Other names:
Large Sandrocket
Lincoln weed
Perennial Rocket
Perennial Wall Rocket (UK)
Sand Mustard
Slimleaf Wall Rocket (USA)
Wall Rocket (USA)
Summary:
Sand Rocket lobed leaf, foxy smelling, erect perennial plant usually less than a metre tall with annual tops. It has hairless stems and the basal leaf rosette usually absent. The yellow, 4 petalled 25 mm diameter flowers can occur at any time of the year with a flush in summer. The cylindrical pod is 20-60 mm long and 2 mm diameter with a short beak and 2 rows of seeds separated by a papery lengthwise partition.
It occurs in scattered localities near Perth, Bunbury, Albany, Jerramungup and Esperance.
Description:
Cotyledons:
Two. Heart shaped, folded together lengthwise in the bud. Tip indented. Sides convex. Base tapered. Surface hairless.
First leaves:
Oval, edge slightly serrated. Tip round. Hairless.
Leaves:
Often clustered near the base but doesn't form a rosette.
Stipules -
Petiole - Yes.
Blade - Dark green, 15-150 mm long by 3-65 mm wide, fleshy. Usually deeply and irregularly lobed. Side lobes are parallel sided and slender. Tip acute. Foxy smell. Hairless or sparsely hairy with most hairs on the stalk or blade edge.
Stem leaves - Maybe none, or clusters or separate. Bluish green, fleshy, mainly hairless. Similar to lower leaves, but less lobed, toothed or without lobes. Foxy smell when crushed.
Stems:
Slender, erect or low lying then sweeping upwards, round, usually 200-700 mm tall and up to 1300 mm tall, many branched, often with a whitish bloom, leafy, woody base. Usually several arising from the rootstock. Hairless or sometimes hairy near the base. Occasionally purple near the base.
Flower head:
Flowers, borne in small clusters or singly, near the tops of the stems on stalks that bend away from the main stem.
Flowers:
15-30 mm diameter with 4 yellow petals.
Bracts -
Ovary - On a distinct stalk (stipe) above the pedicel. Stipe, 0.5-2 mm long when in fruit. Stigma capitate.
Sepals - 4, spreading, 4-6 mm long.
Petals - 4, yellow turning violet with age, 8-15 mm long, clawed.
Stamens - 6, free. Filaments without appendages. 4 nectary glands at the base of the stamens.
Anthers -
Fruit:
Cylindrical, slightly flattened, straight, upright, 2 celled, seed capsule or pod, 20-60 mm long by 1-2.5 mm wide, on a stalk, 15-40 mm long, that sticks out from the stem and is about half as long to longer than the pod. Short, 1.5-2.5 mm long, 2 edged, seedless beak that is narrower than the stigma. Many seeds (50-80) in 2 rows separated by a lengthwise papery partition. Valves 1 nerved. Opens when ripe to release free seed.
Seeds:
Brown to light yellow, egg to tear shaped, small, 2 mm long by 1-1.5 mm wide, finely dimpled.
Roots:
Stout, deep, often branched taproot.
Key Characters:
Hairless stems or with a few hairs near the base. Petals 9-12 mm long. Fruit has a 0.5-2 mm stalk (stipe) above the pedicel.
Biology:
Life cycle:
Perennial. Germinates autumn/winter grows slowly through winter then rapidly in spring, forms a deep perennial taproot system and flowers over summer. Top growth tends to die off each autumn and is replaced by new growth that emerges from the woody rootstock in winter and flowers mainly from January-August. Flowering can occur at any time of the year especially if the plant is damaged. The taproot persist for some years.
Physiology:
Reproduction:
By seed and from taproot.
Flowering times:
Most of the year in SA.
February to April and October in Perth.
Summer in NSW.
Seed Biology and Germination:
Vegetative Propagules:
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Spread mainly by seed as a contaminant of vehicles and railway carriages. Some seed is also spread by animals, on bags and clothing, in mud and by water. Root fragments are spread by cultivation but it generally doesn't persist where cultivation is frequent.
Origin and History:
Southern and central Europe and Western Asia.
Introduced to Australia in the 1800's probably in ships ballast.
Distribution:
ACT, NSW, SA, TAS, VIC, WA.
Habitats:
Climate:
Warm temperate regions.
Soil:
Prefers sandy and limestone soils.
Plant Associations:
Significance:
Beneficial:
Formerly sown as a pasture species.
Used to bind sand to prevent erosion but not very successfully.
Grazed when in flower, otherwise it is usually ignored by stock.
Does not host Root Lesion Nematodes (Pratylenchus neglectus or thornei) (63)
Detrimental:
Weed of crops causing yield reductions due to competition.
Weed of pastures, roadsides, railways, railway yards, cultivation and disturbed areas.
Probably taint milk and meat.
Contaminates crop grain at harvest with green material.
Depletes moisture reserves in fallows.
Toxicity:
Suspected to be toxic.
Legislation:
Noxious weed of South Australia an Victoria.
Management and Control:
Grazing does not provide control. Introduce perennial pasture species if possible.
Difficult to control with herbicides. Cropping and the use of glyphosate and sulfonylurea herbicides reduces infestations.
Thresholds:
Eradication strategies:
Deep ploughing to control the perennial taproot followed by multiple cultivations to control seedlings is effective. Establishment of competitive pasture species will usually prevent reinfestation.
Individual plants can be removed manually but the root must be removed to at least 150 mm deep.
Repeated applications of hormone herbicides are required for control. Sulfonylurea herbicides provide good control.
Herbicide resistance:
Biological Control:
Related plants:
Wall Rocket (Diplotaxis. muralis) is very similar but is usually a smaller annual and has bristly hairs on the stems and leaves. The petals are shorter (4-7 mm long), the pedicel is shorter (usually less than half the length of the pod) and the fruit has no obvious stipe (or stalk above the pedicel and under the pod). Upper stem leaves may be sessile.
Plants of similar appearance:
Radish, turnips and mustards.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P133. Diagram.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P378-379.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P323. Photo.
Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P118-119. Photo.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #451.2.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P164.
Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P342-344. Photos.