The answer to 'why is my weed control' is that there are several common causes for poor weed control, including improper application of herbicides, too much competition from weeds, or the wrong type of weed control product being used. Symptoms of ineffective weed control include seeing more weeds growing in your lawn or garden, weeds that keep coming back, or weeds that are resistant to the products you're using.
Some solutions to improve your weed control include making sure you're applying herbicides properly, using the right type of weed control product for the weeds you have, and addressing any underlying issues like poor soil health or excessive weed competition. For more complex weed problems, it's often best to call in a professional landscaper who can properly diagnose the issue and recommend the best treatment approach.