Almost all flowering plants produce seeds or seed pods after the flowers die. The reason for deadheading spent flowers is to prevent the plant from putting energy into producing seeds. Some of the most beautiful flowering plants produce seed pods with sharp spines or thorns. The spines may be the plant's method of keeping animals that might ordinarily eat the seeds from doing so. Many of these plants are extremely poisonous. Some, though enjoyed as ornamental flowering plants by gardeners, are considered weeds in certain locations.
This white angel's trumpet is characterised by large trumpet-shaped upward facing flowers that open at dusk and close in the morning. Flowers are fragrant, and though white, can be tinged with pink or purple. It is native to Mexico and the southwestern United States. In the south, it is a low-growing and spreading perennial, but it is considered an annual in northern locations like Britain. Immature seed pods are green, but as the seed pod matures, the spikes are more pronounced. When the seed pods are finally ripe, they will dry out and turn brown. Fully ripe seed pods often burst open, spreading seeds through the wind and on the ground.
Also known as "thorn apple," this member of the nightshade or Solanaceae family is an upright growing plant. New growth develops from underground stems. In the southernmost United States, Datura stramonium grows in the wild, along roadsides, in fields, abandoned home sites and waste places. Leaves have teeth-like margins and pointy tips. The base of leaves develops to a narrow point. At the end of stems, bisexual tubular to funnel shaped flowers emerge. Flowers are white to lavender and have tendrils at the outer edges of the petals. The fruit of this plant is a spiny capsule that holds the seeds. The green seed pod grows as it matures and then turns brown upon ripening.
Castor bean or Ricinus communis is a member of the Euphorbiaceae or spurge family. It is an upright perennial herb that forms an arbor. It usually doesn't grow taller than 3.6 m (12 feet) in height. Although it prefers to grow in semi-tropical places, it also grows in old fields, at the edge of gardens and at the site of abandoned homes. You are more likely to find it in greenhouses in the UK. It is characterised by palmate lobed, dark green to reddish leaves. Flowers are large spikes that produce fruit or spiky burr-like seed pods that turn red while maturing. Smooth and mottled seeds are used to distil castor oil. It is sometimes grown as an ornamental plant. It produces seeds prolifically and winds carry seeds to garden edges and other places where eventually, stalks are killed by frost. This colourful plant is also one of the most deadly plants there is. A single seed can kill a child. It is also deadly because after castor oil is extracted from the seeds, the remaining powder is used in the manufacture of Ricin. In tropical places in the New World, castor bean oil is refined as a liniment, a laxative, a purgative and a fever reducer. Liniment is used to relieve the pain of sore and aching muscles.
Clytostoma callistegiodes is a member of the Bignoniaceae or trumpet creeper family. It is commonly called violet trumpet vine, painted trumpet or Argentine trumpet vine. This fast-growing relative of cross vine is characterised by its showy flowers. As a woody evergreen vine, it has a habit of using its tendrils to attach nearby plants, fences and other structures. Oblong, bright, glossy green leaves measure about 7.5 cm (3 inches) in length and 3.7 cm (1 1/2 inches) in width. In late spring, it produces a spectacular display of 7.5 cm (3 inch) lavender trumpet flowers. After flowering, it produces large, prickly seed pods. It is native to Argentina and Southern Brazil.