Native to certain parts of the Americas and the Caribbean, annual ragweed is a widespread noxious weed in most temperate regions of the world, as well as in the Indian subcontinent. It is a prolific seed producer with a strong root system - a mature plant is nearly impossible to pull out and regrows after being cut back. Annual ragweed thrives in disturbed land where it quickly outcompetes any native vegetation, so it frequently appears in tilled fields, abandoned construction sites, wastelands, and burned areas. Additionally, the wind-carried pollen is highly allergenic, and it causes allergic reactions from August well into the fall.

The best time to remove weeds is before their flowering and fructification, otherwise controlling them can be very difficult. After they have flowered and fructified, their seeds can spread very fast, and hence, the weeds should be removed more often and precautions should be taken in advance in the following year. Mulching: During the seed stage, covering the soil with sawdust, straw or black mulches can effectively inhibit seed germination and the growth of seedlings. In the winter or spring, this method is often used to inhibit the seeds in the soil from germinating. If the weeds have already flowered and fructified, then the method can also be used to prevent more seeds from falling into the soil. Pulling out: Wear gloves or use tools to remove weeds before their fructification. If the soil is too dry, then water the soil thoroughly to make it softer, which can help to remove the root systems of the weeds. After that, deep tillage can be adopted to remove bits of weed roots left in the ground. This method works particularly well for weeds that are low-growing or in their seedling stages. Take care when removing it, as it is allergenic. Mowing: Mowing weeds before their fructification can effectively control their spread. Especially for annual weeds, frequent mowing can inhibit their growth and fructification, and thus can remove them effectively within the year. Ploughing: Be sure to plough and pull out all roots of perennial weeds before planting. The roots should be discarded, exposed to the sun for a long time, or buried deep. You can also use the roots to make organic fertilizer and compost the weeds. It can be effectively removed with herbicide. Note: When removing weeds, especially those which are toxic, thorny and have allergenic sap, be sure to wear gloves and avoid direct contact with them. When removing weeds during their bloom time, be sure to wear special masks to prevent pollen allergy.