WEEDS Science Page WEED LIFE CYCLES DID YOU KNOW? Annual weeds Biennial we eds Perennial weeds

.usbg.gov Weeds are plants growing complete their live for two live year to year. life cycle in a growing where they are not wanted. Perennials die ww w They can quickly grow and take single season. seasons. to the ground

over bare patches of soil. Weed During the first each growing season. But seeds can be buried in the soil growing season, they their for many years. When they are Seeds of annuals make food that underground uncovered, they can still sprout sprout a nd is stored in the ir roots or ste ms and grow. grow into underground stay alive and send up new mature stems or roots. plants. In the second shoots at the start of the After season, they UNITEDSTATES BOTANIC GARDEN Seeds of making use the stored each growing evening seeds, t he food to make season.

primrose plants d ie. flowers and can yellow seeds. sprout a nd lambsquarters Queen Anne’s lace nutsedge

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being buried WEED SEEDS Dandelion in the soil for over 100 Most weeds make seeds have years! lots of seed s. parachutes that float in

Weeds also the wind. have unique

Burdock evening primrose ways to seeds hitch a spread their ride on fur seeds. and clothing.

WEEDS ARE HARDY WEEDS GROW FROM PLANT PARTS Most weeds can Many

grow very weeds can Field bindweed grows lots of rapidly, and also sprout roots. New they can grow from roots, A small piece of plants sprout in many stems, or stem or leaf of up from the different places. leaves. common purslane roots. can grow into a fireweed new plant.

WEEDS CAN BE FRIENDS...... AND CAN BE FOES! While weeds can become pests in fields, lawns, and gardens, It can be difficult to get rid of they can also be useful. They can be used as food or medicine weeds, especially in areas for humans and animals. They can protect and improve the where humans have soil. They can also be beautiful to look at! disturbed the soil. Weeds can reduce crop yield in fields and Weeds quickly gardens. sprout and grow on bare soil, and keep it from Where did all these washi ng or weeds come from? blowin g away. lambsquarters

bugleflower gill-over-the-ground

Many weeds, such as comfrey, have been used as food and medicine for burdock hundreds of years.

Deep-rooted weeds can bring up nutri ents chicory from deep in the soil. When they die, dandelion Weeds compete with crops for space, weeds add organic matter to the soil. water, sunlight, and nutrients. UNITED STATES BOTANIC GARDEN www.usbg.gov

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