Posted on

weed that propels seeds

Pest Information

Native to Europe, but widespread throughout the United States, and a severe problem in turf and landscape, nurseries and greenhouses, as well as some cultivated crops.

A perennial weed that is very similar to yellow woodsorrel, the difference being the method of spreading. Creeping woodsorrel spreads by stolons above ground that root at the nodes, while yellow woodsorrel spreads by rhizomes below ground that sprout new stems. Propagation also is by seeds, and dispersal of the seeds is done by an explosive opening of the seed pods that propels the seeds over 10 feet away. In cooler climates the foliage of plants dies back, with re-growth from the roots.

Mature plants are generally low lying and mat-like, growing as high as 6 inches but potentially spreading many feet laterally as the stems grow. Stems are creeping and will form roots at the nodes, increasing their ability to cover wide areas. Leaves vary from yellow-green to green to a violet-purple. Leaves are clover-like, with three heart-shaped leaflets on long stalks. After sunset the leaflets tend to fold down along their stems. Flowers are yellow and may grow in small groups of up to six flowers, each on a long stalk. Flowers are very small but open wide, and have 5 petals. The seed pod is a cylindrical capsule up to an inch long, often pointing vertically. It contains many seeds, and is capable of throwing these great distances as it pops open. Seeds also have a sticky coating and may be carried in animal fur.

Characteristicts Important to Control:

See also  can you bring weed seeds airplane

Physical removal in turf is almost impossible due to the extensive system of rooted stolons. Control should be done prior to seed production and dispersal.

Floral Fireworks: Plants that Explode

In the spirit of Independence Day, I thought I’d share with you some explosive plants–plants that put on their own fireworks displays.

While some plants produce enticing fruits to persuade animals to carry their seeds away, other plants do the job themselves, propelling their seeds as far as they can. Often, these explosive dispersals depend on evaporation. The sun’s warmth removes water from the seed pods, forcing them to open and squeeze out their seeds. A variety of plants opt for this ballistic dispersal, including geraniums (right, post-dispersal in rear of picture), certain types of orchid, Oxalis, and lupine. We’ll just focus on a few here.

Touch-Me-Not (Impatiens capensis)

Touch-me-not, also known as jewelweed, grows across the United States except in the Southwest, Montana, and Wyoming. It can be recognized by its orange, trumpet-shaped flowers and bluish-green leaves. Jewelweed seeds are encased in a sensitive pod that peels back at the slightest pressure, launching its seeds into the air. Though this creates an impressive show (see this video from the Smithsonian Channel), seeds typically do not travel far, remaining within 2 meters of the plant.

Exploding Cucumber (Cyclanthera explodens)

Technically a gourd, this fruit is edible, but it puts up a fight. In addition to a spiky exterior, the 2-inch exploding cucumber peels open suddenly to propel its seeds several feet. Exploding cucumbers hail from southern Mexico through Central America down to Ecuador, but they are grown elsewhere because they are kind of fun to have around.

See also  golden goat seeds

Squirting Cucumber (Ecballium elaterium)

This Mediterranean plant technically is a cucumber, but it’s poisonous. A hairy-looking pod grows on a long stalk, filling with juice until it can no longer take the pressure. Suddenly it bursts free, projecting a slimy mix of cucumber goo and seeds into the air, up to 20 feet away from the plant (see the Smithsonian Channel’s video).

Also called the sandbox tree, Monkey no-climb, Possumwood, and jabillo, this poisonous, tropical tree is one step closer to a fireworks display in that it produces a loud cracking sound when it releases its seeds. Pumpking-shaped seed pods dry out and shake in the branches of the tree, until eventually the segments burst apart with a thunderous crack that propels seeds over 40 feet from the tree.

This isn’t an example of seed dispersal, but the bunchberry dogwood produces a tiny explosion (and holds a special place in my heart) as the fastest-opening flower in the world. Cornus canadensis opens in less than 0.4 milliseconds–that’s less time than it takes a bullet to travel the length of a rifle barrel. Its initial acceleration is more than 2400 times the acceleration of gravity. In North America, the sub-shrub’s range stretches from Atlantic to Pacific, with small inflorescences containing 20 to 50 flowers (flowers open to reveal a small, plum-colored interior). This flower’s energetic explosion propels pollen ten times the height of the flower–that is, an impressive 2.5 centimeters into the air.