Short, Yellow Brassicas
What are they?
This page covers members of the brassica family that typically grow less than 70cm in height and have yellow or orange - usually (although not always) showy - flowers. Since the group includes a number of species that are not particularly closely related, they differ quite widely in their appearance, which should actually help with the identification process. They all share the family traits of four-petalled flowers that are followed by distinctive seed capsules. Some of the plants that lead you here may be shorter individuals of species that will often grow taller, so they are also included in the page on tall, yellow brassicas and it is always worth checking both these pages when making an identification.
Where are they found?
This is a group of only loosely related plants, so there is much variation in the habitat choices - from arable farmland and grassland to waste ground, urban habitats and wetlands. However, the habitat can be a valuable aid to identification for some species, so be sure to check these details in the individual species notes below.
Identification
All these plants have yellow (or orange), four-petalled flowers, so you need to look elsewhere for identification clues. Start with noting shape of the leaves - both basal (if present) and stem leaves, especially noting whether they are simple or compound and whether the stem leaves have stalks or clasp the stem. Finally, the shape of the seed pods can be very useful and should be studied carefully; overall size and shape should be noted, as well as the size, shape and hairiness of the 'beak' - the usually elongated tip of the seed capsule that typically contains no seeds.
Common Wallflower Erysimum x cheiri
Introduced. A popular garden plant in a variety of colours, but the plant was perhaps first introduced in the 11th Century and is now well established throughout our region, growing out of old walls. Flowers April to June. The distinctive, rich, golden-yellow flowers are a well-known spring sight, making the plant readily recognised. It is an evergreen perennial and the leafy, dark green tussocks persist throughout winter. Leaves are slightly fleshy, allowing water to be retained during hot, dry spells. Cultivated forms come in a variety of reds, oranges, yellows and even white, but self-sown populations all seem to revert back to the golden-yellow flowers of the species.
For a long time considered to be a true species, recent research indicates that Common Wallflower appears to be a hybrid between Erysimum corinthium and another, as yet uncertain, species, that probably originated in the wild in Greece.
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Siberian Wallflower Erysimum x marshallii
Introduced. A hybrid of garden origin with no connection to Siberia! Often used for bedding schemes in municipal plantings and occasionally occurring as a garden escape or throw-out, but never persisting. Flowers March to July. Flowers bright orange and leaves narrow, but perhaps best told from Common Wallflower by the tip of the seed pod, which has stigmas that are small and rounded and pressed closely together, not forming a strongly bifid tip.
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Dwarf Wallflower Erysimum suffruticosum
Introduced. Grown as a garden plant and increasing in popularity in recent years, seedlings of this plant have been found self-sown in pavement cracks in Great Yarmouth and it may well appear elsewhere in urban environments. Flowers March to June. Very like Common Wallflower but smaller in all parts and usually less than 25cm in height. Flowers bright yellow, the unopened buds usually tinted deep reddish. Note that most modern taxonomies consider this plant to be just a small form of Common Wallflower.
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Common Treacle-mustard Erysimum cheiranthoides
Introduced from mainland Europe. Widespread annual or biennial on arable land and allotments, most frequently on the boulder clay soils of central East Anglia. Flowers May to October. Typically 15-90cm in height with simple leaves that are entire or have a few, shallow teeth on the margin.
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Golden Alison Aurinia saxatilis
Introduced as a garden plant and rarely being found as an escape from cultivation on walls and banks in urban or suburban areas. Flowers April to June. With its habit of growing from stone walls, this plant could be confused with Common Wallflower, but its flowers are quite different, being smaller and carried in large clusters that clothe much of the plant during spring. The greyish-white leaves are also very different to those of the wallflowers.
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Small Alison Alyssum alyssoides
Introduced from mainland Europe and long known from a small handful of sites on sandy soil in Breckland and the Suffolk Sandlings. Now very rare and perhaps only surviving in one or two locations where it is managed. Flowers May to June. A small and easily missed plant, growing to 25cm but often much less. Flowers are small and hard to spot when nestled among the whitish sepal hairs but the combination of these small, hairy flowers, the covering of bright white, stellate hairs on all green parts of the plant and the disc-like seed capsules is diagnostic in our region.
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Strigose Alison Alyssum strigosum
Introduced from mainland Europe, probably as an impurity of imported grain. Recorded just once from Suffolk in the late 19th Century. Flowers May to June. Very similar to Small Alison but more roughly hairy and with shorter, spoon-shaped leaves.
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Common Winter-cress Barbarea vulgaris
A native biennial or short-lived perennial, found throughout East Anglia in all but the driest, sandy soils. Occurs in a variety of grassy and disturbed places, especially roadsides. Flowers April to July. Winter-cresses have rich yellow flowers and glossy green leaves, the latter first appearing over winter rather than in the spring. Basal leaves with broadly rounded leaflets; upper stems leaves more or less entire with toothed edges, not deeply lobed. Flower buds hairless.
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Early Winter-cress Barbarea verna
(American Winter-cress) Introduced from south-west Europe, despite the alternative English name! An uncommon to rare biennial or short-lived perennial, found scattered throughout the region in a few areas of rough ground and waste places. Long-known around the Felixstowe area especially. Flowers March to June. Winter-cresses have rich yellow flowers and glossy green leaves, the latter first appearing over winter rather than in the spring. Basal leaves with 4-10 pairs of small, rather angular leaflets; upper stems leaves deeply cut into finger-like lobes. Petals usually more than 5.6mm in length and at least some ripe seed capsules over 40mm long.
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Medium-flowered Winter-cress Barbarea intermedia
Introduced from mainland Europe. An uncommon to rare biennial or short-lived perennial, found scattered throughout the region in a few areas of rough ground and waste places. Flowers March to June. Winter-cresses have rich yellow flowers and glossy green leaves, the latter first appearing over winter rather than in the spring. Basal leaves with 2-6 pairs of small, rather angular leaflets; upper stems leaves deeply cut into finger-like lobes. Petals usually less than 5.6mm in length and ripe seed capsules less than 40mm long.
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Creeping Yellow-cress Rorippa sylvestris
A native perennial of damp ground and also occasionally a weed in gardens and disturbed areas. Flowers June to August. A low-growing species that spreads and forms persistent mats of vegetation; flowering shoots can reach 60cm in height, but often much shorter. Lower leaves with toothed leaflets, upper leaves more or less reduced to a row of finger-like leaflets.
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Marsh Yellow-cress Rorippa palustris
A native annual or short-lived perennial of damp ground, found in small number along waterways and occasionally ponds or wet depressions, throughout the region. Flowers June to August. A small (usually to about 60cm) species with stems not rooting to form mats. Flower petals only about as long as the sepals. Leaves very variable, from deeply lobed to more or less entire with serrated edges.
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Perennial Wall-rocket Diplotaxis tenuifolia
An ancient introduction, most often found in urban or suburban areas and locally common around Great Yarmouth, Lowestoft, Ipswich and Mildenhall, with scattered populations elsewhere. Flowers May to September. A winter-green perennial, with plants often growing to nearly a metre in height and forming rounded, bushy mounds. Compared with Annual Wall-rocket, leaves are more deeply cut, plants grow overall much larger and the stalks of the ripe seed capsules are much longer.
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Annual Wall-rocket Diplotaxis muralis
Introduced from southern Europe and widespread, though generally most common on lighter, sandy soils. Most frequent as a garden annual weed and often found growing from wall bases and pavement cracks. Flowers May to September. A much smaller and less branched species that Perennial Wall-rocket. Compared with Perennial Wall-rocket, leaves are less deeply cut, plants are shorter (less than 50cm) and the stalks of the ripe seed capsules are shorter.
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Charlock Sinapis arvensis
An ancient introduction of all kinds of disturbed ground, especially arable farmland. Common and widespread, though generally absent from the more acidic, sandy soils. Flowers May to July. Usually less tall than the Brassica species and usually more obviously branching. A green, slightly bristly plant with yellow flowers and often a reddish tint to the stems. Lower leaves coarsely and irregularly lobed, upper leaves variably toothed or entire, but not clasping stem at base. Flowers with sepals clearly reflexed (compare with Chinese Mustard, which is similar). Seed capsules are narrow with an elongated, slightly flattened beak, which may be hairless or slightly hairy. Beak typically at least a third as long as main part of seed capsule and often much more.
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Wild Radish Raphanus raphanistrum subsp. raphanistrum
Probably an ancient introduction from Neolithic times and now a widespread and common plant throughout most of our region on a wide range of disturbed ground, field margins, waste places, tips and similar locations. Flowers May to September. Once known, this is an easy plant to recognise, with its coarse, bristly leaves and stems and its seed capsules that have faint ribbing between the developing seeds. Plants are often relatively short, but usually have spreading branches, making them more noticeable and obvious than the species covered under the small, white brassicas. Flowers usually have dark veins and populations usually have a mix of both white and pale yellow flowered plants among them. The petals have long bases to them, forming a distinct cross shape.
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Sea Radish Raphanus raphanistrum subsp. maritimus
A native biennial or short-lived perennial which is locally common along the coast on muddy soils, especially in the Lowestoft and Great Yarmouth areas. Flowers June to August. Very similar to Wild Radish but, being longer-lived, it more often forms larger, many-branched clumps with more woody stems. Flowers usually bright yellow but occasionally white. Seed capsules on average are shorter than those of Wild Radish, with fewer seeds inside and are strongly constricted between each seed.
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Hedge Mustard Sisymbrium officinale
An ancient introduction, now firmly established and widespread as a common weed of all types of cultivated and waste places. Flowers May to July. An upright plant with, eventually, a much-branched flowering head. Plants start flowering when still small, single-stemmed and with a well-developed basal rosette of sharply compound leaves. As the plant develops, the basal leaves die off, but the plant continues to flower and forms side branches, each side branch progressively elongating as the seed capsules ripen. Thus, this plant has many guises, but its tiny flowers and its pods pressed close to the stem make a distinctive combination.
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Pale Rocket Sisymbrium irio
(London Rocket) Introduced from southern Europe. A very rare species with less than ten records from our region and no current populations known. Flowers June to August. An upright, sometimes branched species with pale yellow flowers, deeply lobed leaves and very long seed capsules that usually overtop the open flowers.
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Gold-of-pleasure Camelina sativa
Introduced from Europe but native range is uncertain as it has been in cultivation for some 3000 years. Periodically favoured for a variety of uses and occasionally occurring from spilt bird seed and formerly as a scarce crop weed. Recently becoming more frequent due to its inclusion in pheasant cover strips. Flowers May to October. An upright, usually well-branched species with simple leaves and rounded seed capsules that are 9-13mm long.
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Wallflower Cabbage Coincya monensis ssp. cheiranthos
Introduced from southern Europe. A rare species in our region that ocasionally appears as a short-lived introduction. A small population has persisted for many years in East Suffolk and a new population was found in North Norfolk recently. Flowers May to September. A variable species with several subspecies, often upright to a metre in height but may be shorter and more sprawling. Flowers pale yellow, leaves distinctively deeply lobed.
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Southern Warty Cabbage Bunias erucago
Introduced from southern Europe, either accidentally or occurring as an escape from cultivation. Once recorded from Cambridgeshire in the 1930s. Flowers May to July. A small plant growing to 30-60cm in height. Best identified by its very distinctive seed capsules, which have sharply toothed wings on them. Stems studded with reddish, glandular bumps.
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