Short, Yellow Brassicas

Golden Alison Sea Radish Marsh Yellow-cress Hedge Mustard

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 pods. 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 pod that typically contains no seeds.



Common Wallflower      Erysimum cheiri

Introduced. A popular garden plant in a variety of colours, but the true species 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.

Common Wallflower Common Wallflower Common Wallflower Common Wallflower
Habit
Flower
Flowers
Leaves


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.

Dwarf Wallflower Dwarf Wallflower Dwarf Wallflower Dwarf Wallflower
Habit
Flower
Flowers
Leaves


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.

Golden Alison Golden Alison Golden Alison Golden Alison
Habit
Flowers
Flowers
Leaves


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 pods is diagnostic in our region.

Small Alison Small Alison Small Alison Small Alison
Habit
Flowers
Stellate hairs
Seed pods


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 May to July. Winter-cresses have rich yellow flowers and glossy green leaves, the latter 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.

Common Winter-cress Common Winter-cress Common Winter-cress Common Winter-cress
Habit
Flowers
Basal leaf
Upper stem leaf


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 May to July. Winter-cresses have rich yellow flowers and glossy green leaves, the latter appearing over winter rather than in the spring. Basal leaves with 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.

Early Winter-cress Early Winter-cress Early Winter-cress Early Winter-cress
Habit
Flowers
Basal leaf
Upper stem leaf


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.

Creeping Yellow-cress Creeping Yellow-cress Creeping Yellow-cress Creeping Yellow-cress
Habit
Flowers
Leaf
Leaf


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. More or less intermediate between the previous two species; being relatively small (usually to about 60cm) but not mat-forming. Leaves very variable, from deeply lobed to more or less entire with serrated edges.

Marsh Yellow-cress Marsh Yellow-cress Marsh Yellow-cress Marsh Yellow-cress
Habit
Flowers
Leaf
Seed capsules


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 pods are much longer.

Perennial Wall-rocket Perennial Wall-rocket Perennial Wall-rocket Perennial Wall-rocket
Habit
Flowers
Leaf
Seed pod


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 pods are shorter.

Annual Wall-rocket Annual Wall-rocket Annual Wall-rocket Annual Wall-rocket
Habit
Flowers
Leaf
Seed pods


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 pods 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 pod and often much more.

Charlock Charlock Charlock Charlock
Flowers
Lower leaf
Upper leaf
Seed pod


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 pods 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.

Wild Radish Wild Radish Wild Radish Wild Radish
Flower
Flower
Basal leaves
Seed pod


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 rarely white. Seed pods on average are shorter than those of Wild Radish, with fewer seeds inside and are strongly constricted between each seed.

Sea Radish Sea Radish
Habit
Seed pod


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 pods ripen. Thus, this plant has many guises, but its tiny flowers and its pods pressed close to the stem make a distinctive combination.

Hedge Mustard Hedge Mustard Hedge Mustard Hedge Mustard
Habit - young plant
Habit - older plant
Flowers
Basal leaf


Tall Rocket      Sisymbrium altissimum

Introduced from southern Europe and now well-established in the light, sandy soils of Breckland, mostly as an arable weed. Occasional elsewhere on similar, sandy soils. Flowers June to August. Growing to around 100cm in height, this is a distinctive plant with its compound leaves cut almost to the veins, pale yellow flowers and wiry, very long seed pods.

Tall Rocket Tall Rocket Tall Rocket
Habit
Flower
Leaf


London Rocket      Sisymbrium irio

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 pods that usually overtop the open flowers.

London Rocket
Habit