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.

All parts of common columbine, including the stem, leaves, flowers, and seeds, are toxic when they are ingested raw. Contact with the plant's sap may also lead to dermatitis (skin irritation and inflammation). The symptoms from common columbine poisoning are likely to cause only mild to moderate effects, but the symptoms are not well-known, since there are few documented cases of it. Adverse effects are most likely to occur from accidental ingestion.

Smoketree is a deciduous tree native to Southern Europe and Central China. The flowers of the smoketree are pinkish-purple and long-lasting. They grow in clusters along branches and give a smoky appearance to the tree when in bloom. In China, they are used as important fall decorations due to their foliage turn bright red in the fall.

Common barberry is a shrub with unpleasant-smelling flowers and red berries. The flowers can be used to create yellow dye while the berries have culinary and medicinal uses in Iran and medicinal use in China that dates back 3,000 years. Despite this, common barberry can be a host to wheat rust that is highly damaging to grain crops in America.

A garden poppy that can escape as a scrambling weed across open fields, the common fumitory (Fumaria officinalis) produces flowers from early spring to late fall. In the past, it had been used as a folk medicine, but it is now known to be poisonous and should not be used in any home remedies.

Spanish broom is a deciduous shrub native to the Mediterranean, West Asia, and North Africa. Fragrant yellow pea-like flowers cover the shoots in late spring and summer. It is cultivated for its ornamental value and is used for flavoring and essential oil extraction.

As the name infers, the poison hemlock is a highly poisonous plant and has been known to intoxicate a variety of livestock. The leaves are similar to carrots and parsley, fooling most herbivores into consuming it. Poison hemlock can be lethal when ingested.

Hairy willowherb (Epilobium hirsutum) is a species of weed that is difficult to eradicate. It is not known to be toxic, but the sale of this plant or its seeds has been banned in some areas. This is because its dense, aggressive growth habits can crowd out and destroy other native beneficial plants.

Autumn crocus (Colchicum autumnale) is a flowering plant native to the coast of the Mediterranean and the Black Sea. Its flower stalks grow up after a period of time after its leaves die out, so you can see its flowers or leaves but never both. Consumption of autumn crocus is toxic and is particularly poisonous to cats. Autumn crocus is not the source of saffron. Saffron is produced by another species in the crocus family.

Bearded iris is known to cause contact dermatitis in some individuals. The most commonly reported symptom is minor skin irritation, typically lasting only a few minutes. This can result from contact with the seeds, roots, or sap of this plant. Furthermore, all parts of bearded iris are toxic when ingested, especially the roots. Symptoms typically including minor or moderate burning sensations, nausea, vomiting, abdominal pain, diarrhea, and fever. This plant is most often encountered in a garden context, where it is planted as an ornamental.

True to this plant's reputation, consumption of potato can be extremely toxic to dogs, and warrants immediate veterinary attention. All parts of these plants contain several toxic substances which can cause loss of appetite, excessive drooling, vomiting, diarrhea, dilated pupils, confusion, behavioral changes, and weakness. In more severe cases, difficulty breathing, a lowered heart rate, coma, or even death may occur, so treat it as a medical emergency if your pet has come into contact with this plant.

Sun spurge (Euphorbia helioscopia) is a winter annual that grows along the ground in a variety of locations from gardens to wastelands. It features distinctive red colored stems with toothed leaves that emit a toxic milky sap when cut or torn. Pale yellow flowers bloom from spring to summer and give way to fruit. This plant is considered a weed.

The golden chain tree is used as an ornamental in gardens and patios. It gets its name from the cascading yellow flowers that bloom in late spring. The lumber can be used for cabinetry, inlay work, and musical instruments. The flexible branches also used to be important for making bows. The golden chain tree is toxic in its entirety and can be fatal if eaten.

Cow parsnip (Heracleum sphondylium) is a species of flowering perennial herb related to parsley and fennel. Its specific epithet, "sphondylium," means "vertebrate," and references its segmented appearance. This species produces extremely large amounts of nectar and thus attracts many bees.

Rough horsetail (Equisetum hyemale) is an evergreen perennial. An aggressive grower, it reproduces through spores and is non-flowering. It prefers full sun to partial shade and is pest resistant. It provides erosion control, grows well in wetlands and makes an interesting addition to water gardens. Expected height of 61 to 91 cm.

Clematis viticella species are mildly to moderately toxic to dogs. All parts of most italian leather flower plants contain a strong irritant that, if eaten, causes excessive salivation and loss of appetite. This may progress to vomiting or diarrhea. More severe symptoms are possible but very rare, as these plants tend to be extremely distasteful to dogs, and so it's not often eaten in large quantities. Seek veterinary attention if your dog is experiencing the stronger symptoms.

Deadly nightshade or Atropa belladonna is true to its name; this plant, including the foliage, roots, and pretty blueberries, is extremely toxic and can cause death. It is especially toxic to small children, but also can be lethal for animals if ingested.

Cuckoo pint (Arum maculatum) is a perennial that will grow to 51 cm tall. It blooms in spring with male and female flowers that spring be yellow or purple. Male flowers have tiny hairs to trap insects that are attracted by the scent of the blossoms. This entrapment covers the insect in pollen before it can escape to pollinate other flowers. Female flowers give way to bright red berries in summer that are highly poisonous.

If either ingested or touched, dieffenbachia can cause negative reactions. The symptoms range from moderate to severe and can be dangerous if airways are blocked. Due to the calcium oxalate contained in this plant, its leaves and sap have toxic properties. When ingested, they can induce symptoms such as lip and tongue swelling, drooling, speech loss, and difficulty breathing; when touched, they can cause a painful skin rash or eye irritation. Since these plants are often found indoors as decorative plants, be careful when keeping them around small children. Always wear gloves when handling this plant.

Hyacinthus orientalis is one of the heralds of spring. The name common hyacinth comes from the Greek name Hyacinthus. According to Greek legend, Hyacinthus was admired by both Apollo and Zephyrus. Hyacinthus ended up being killed out of jealousy and a flower bloomed on the spot where his blood was spilled. Apollo named the flower after his lost love.