Portulaca oleracea, colloquially known as common purslane, is an annual succulent species with reddish stems and tiny yellow, five-petal flowers. It is used for culinary purposes in various parts of the world, most often raw, in salads. Common purslane is also a good companion plant for crops that thrive in moist soils.

Common sowthistle is a common weed originated in Europe and West Asia. Alongside many sister species that hard to distinguish, it is considered to be an invasive plant in many parts of the world. Its leaves with some bitter taste are editable either green as a part of a salad or cooked in various ways.

Lambsquarters has many other names, including pigweed, goosefoot, and bacon weed. This plant seems to appear out of nowhere and is considered by many to be a pesky weed. However, the greens of this plant are edible, can be prepared similar to spinach, and are packed with nutrients.

Perennial wall-rocket (Diplotaxis tenuifolia) is a plant species that is a member of the Brassicaceae family. Perennial wall-rocket is named for the hardiness of this plant, as well as the plant's tendency to grow out of walls and cliff faces. Perennial wall-rocket foliage is aromatic when crushed.

Nut grass can be found all over the world. This perennial plant gets its name because its tubers resemble nuts. Nut grass is considered one of the most invasive plants in the world, and among the most difficult to eradicate. It reduces crop yields and is resistant to most herbicides.

Pellitory of the wall (Parietaria judaica) is a species of flowering plant that is native to Europe, North Africa and parts of west Asia. It is an introduced species elsewhere in the world and is widely considered a weed. It proliferates in disturbed areas and is sometimes known as “asthma weed” because its pollen is an allergen for many people.

Graceful spurge (Euphorbia hypericifolia) is a perennial flowering bush that blooms all year round. This species grows best in full sunlight or partial shade. Graceful spurge is resistant to rabbits and deer due to its toxic sap. This species is often cultivated as an ornamental plant and grown in containers, hanging baskets and gardens. Gardeners should wear gloves when handling graceful spurge due to its toxic sap.

Matted Sandmat is an annual weed that grows flat along the ground into a matted form. It has a long tap root and hardy seeds, which make it difficult to eradicate. This plant’s sap can irritate the skin and is toxic.

Although its berries look juicy and tempting, the fruits and the root of pokeweed are toxic and should not be eaten. Pokeweed is considered a pest species by farmers but is nevertheless often grown as an ornamental plant. Its berries can be made into pokeberry ink as well.

Petty spurge (Euphorbia peplus) is an annual plant from Europe, Asia, and Africa. It is fast-growing and has become invasive in some countries because it outcompetes other species for resources such as moisture and sunlight. Petty spurge latex is mildly toxic, has nevertheless attracted the attention of researchers in the US and Germany who hope to isolate useful compounds from it.

Yellow horned poppy (Glaucium flavum) is a perennial wildflower that will grow from 30 to 61 cm tall. In mid-spring to early summer, it blooms bright golden-yellow flowers that are 5 cm wide. Prefers full sun and can tolerate drought and seaside locations. Often found growing among sand dunes on beaches. The seeds have been used to make soap.

Small Nettle (Urtica urens) is a herbaceous annual flowering nettle known by many common names. Small Nettle is also called the dog nettle or burning nettle because it "bites" when touching (in the same way as stinging nettle). Small Nettle is native to the Eurasian continent. Butterfly species feed on this plant.

In warmer climates, the downy thorn-apple is an invasive perennial. In colder zones, it’s an annual that can be controlled. It is native to East Africa and is naturalized in China. It is not currently a problem in the United States, but it would become invasive if it were introduced. The reason for this is that the plant will quickly establish itself and spread rapidly. It is cultivated in gardens, but care must be taken to prevent it from overtaking other plants. The weed poses another threat: it is highly toxic to humans and animals. There are not any current bans on the sale, transport, or cultivation of the plant, but it is generally not encouraged.

Field bindweed (*Convolvulus arvensis*) is a native Eurasian plant related to morning glory. It is considered an invasive species in non-native areas because it competes with other plants for sunlight and moisture. Field bindweed is very hard to eradicate because its taproots grow so deep, and its seeds can remain viable for decades.

While the redroot amaranth is considered a weed in most areas, some parts are edible. Fresh leaves may be included in soups and stews, while the dried leaves can be utilized in tea or ground into flour for bread or used as a thickening agent. Seeds can also be eaten, but the stalks, roots, and older leaves contain toxic substances. Redroot amaranth is sometimes used as fodder for livestock - it is nutritious in small amounts but toxic if too much is fed over a span of several days.

Flaxleaf fleabane (Erigeron bonariensis) is an annual plant with distinctive blue-green foliage. Flaxleaf fleabane is considered a weed. This species is often found growing along concrete cracks in driveways and sidewalks. Tt is also found in pastures, gardens and roadsides. Flaxleaf fleabane produces many seeds, which are dispersed by wind and transported by animals, vehicles and people.

Prostrate knotweed (Polygonum aviculare) is a low-growing species that can root practically anywhere. It produces many small white flowers each summer and produces plenty of seeds that can survive for years. Its seeds can lay dormant in soils, and once they see sunlight, they will start to germinate. Because it grows so dwarf, mowing is not effective in removing it.

Black nightshade (Solanum nigrum) is a highly toxic plant and caution should be exercised around this plant. It's said that black nightshade fruits can technically be consumed if they are fully ripe and properly cooked and prepared. Generally though, due to the danger they present, no one would ever want to try to eat this plant.

Experts consider johnson grass (Sorghum halepense) to be one of the ten worst weeds in the world. If frost or heat causes the plant to wilt, it can produce enough hydrogen cyanide to kill livestock. It grows at such a prodigious rate, it can choke out other crops. It’s named after Colonel William Johnson, an Alabama plantation owner who sowed lots of its seed around 1840.

Fourleaf manyseed (*Polycarpon tetraphyllum*) is an annual herb that thrives in sandy or coastal soils. It gets its common name because it grows in a four-leaf pattern and produces quite a lot of seeds. Native to Southern Europe and introduced elsewhere. The plant flowers in spring and summer.