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weeds with spiny seed pods

Wild cucumber (Marah macrocarpus) is a beautiful native plant related to gourds, squash, cucumbers and melons. This perennial vine emerges yearly from a massive fleshy tuber and scrambles rapidly before setting delicate, white fuzzy flowers in clusters. The 4-inch-long, egg-shaped seedpod hardens into a spiny fruit containing several black seeds. Although once used as marbles and jewelry by Native Americans, the seeds are bitter and poisonous.

The most dominant feature of castor oil plant (Ricinus communis) is the mass of round, spiny seedpods that erupt after its white stalk-borne flowers begin to fade. In Sunset’s Climate Zones 23 through 28, H1 and H2, it can overwinter and grow into an impressive treelike plant. The rest of the country enjoys the unmistakable castor oil plant’s large lobed foliage during the growing season and sacrifice it to the winter, treating it as an annual in plantings. This plant’s seeds are the source of castor oil, although it is not recommended that you attempt to press your own.

Prickly poppy (Argemone mexicana) thrives with abuse and reseeds itself readily when given the opportunity. The only parts of this 3-foot-tall poppy that aren’t covered in spines or sharp edges are the 1 1/4-inch-wide yellow flowers. Although treacherous, this poppy is often grown in Sunset’s Climate Zones 7 through 43, 2A, 2B, 3A, 3B, H1 and H2. The seeds germinate readily, often when one of the spiny seedpods drops to the ground and shatters.

Wild Cucumber

Datura innoxia and Datura stramonium are both ornamental plants that grow in Sunset’s Climate Zones 8, 9 and 11 through 31. These 3- to 6-foot-tall perennials boast large, trumpet-shaped flowers and spiny seedpods. Daturas are night-bloomers that release a perfume into the moonlit garden when planted as part of a landscape. Sometimes confused with moonflower, Daturas are in no way related. Datura is a bushy plant related to imsonweed, where moonflower is a climbing vine related to the sweet potato and morning glory. Many Datura plants are poisonous, so take caution in selecting their permanent locations.

Curious nature lovers regularly find unusual plants poking up in their own yards or those of their friends and family. A striking vegetative combination like spiny seedpods and flowers is bound to get the attention of an onlooker. Whether you’d like to add more of your newfound plant to the landscape or obliterate it completely, it helps to know what kind of plant you’re dealing with. Several plants sport spiny seedpods and flowers.

Other plants with spiny seedpods and flowers that grow wild could be either puncturevine (Triblus terrestis) or California burclover (Medicago polymorpha). Both are considered weedy plants in many Western states. Puncturevine is mat-forming weed with small, oval-shaped leaves on long stems that generally lie along the ground. It sports small yellow flowers and produces razor sharp, spiny seedpods that can puncture bicycle tires. California burclover is a member of the pea family and strongly resembles white clover. However, its three-part leaf is made of three small leaflets, each held on its own short stem. California burclover can grow up to about 2 feet, but generally lies along the ground. Flowers are small and yellow, eventually giving way to seedpods with two or three rows of prickly hooks.

Jimsonweed occurs in the warmer parts of southern Ontario in cultivated fields and around farmyards.

It is distinguished by its tall, stout, branched stem (like small trees), large leaves, large, white or purplish trumpet-shaped flowers, large spiny seedpod and sour repulsive odour.

All parts of the plant are poisonous.

Distinguishing Features

Cotyledons (seed leaves) are narrow and about 2-4cm long, shriveling but persisting on the developing seedling. The first true leaves are ovate with pointed tips and few or no lobes. Later leaves distinctly alternate (1 per node), usually somewhat coarsely and sharply toothed or lobed, 10-20cm long and long-stalked.

Stems stout, erect, 90-200cm high, usually much-branched in the upper part, smooth and hairless. Larger plants will have a main stem often 5cm or more in diameter.

Flowers and seedpods short-stalked, borne singly in the angles between 2 or more stems and a leaf. The calyx is tubular or urn-shaped. The corolla is white or light purple, very long, tubular or trumpet-shaped, 7-10cm long with the flared end having 5 points. The seedpod is at first green and fleshy with sharp, soft spines, becoming a large (2-5cm across), dry, hard seedpod covered with very sharp, harsh spines and containing numerous black, flat, round seeds. Flowers from July to autumn.

All parts of the jimsonweed plant are poisonous and are fatal if consumed in high quantities. Its toxicity is caused by tropane alkaloids.