If the herbicide is atrazine, then yes, absolutely. The USDA just published that about atrazine. The more often you use it, the less effective it is. Nevermind that, weed and feed almost always has no effect on weeds. It is just about the worst product made for lawns. Why? Because weeds die best when they are well fertilized. If you apply herbicide and fertilizer at the same time, the weed killer goes to work right away on the unhealthy weeds and fertilizer takes 2 weeks to kick in. So by the time the weeds are healthy enough to uptake the herbicide, it's dissipated. Not only that but you probably don't need fertilizer at the beginning of spring. It is much better to apply fertilizer after you are mowing the grass and even into May. Then apply 2/3 to 3/4 of your annual fertilizer in the fall. But if you want to kill weeds, fertilize now (I know I just said not to) then come back in 2 weeks with Weed-B-Gone spray and spot treat the weeds that are left. Or, if you already used the weed n feed, then wait 2 weeks and spray with Weed-B-Gone.

Wow! Really...and my husband's name is William. He was about to go at it with the weed wacker and I was surprised to see it there and told him not to. He's going to love that I found out it's "Sweet William"! Thanks so much for your quick responses!

I really appreciate all the comments. So yesterday I went back and took more and better pictures. #1, it is definitely growing back from a tree that was cut down. #2, I took a picture comparing it with my mimosa seedling and it didn't look like it (see pic). #3, I think the leaflets are too small for honey locust. I did look at Leucaena leucocephala but I get anywhere. It could be what it is, I did notice that the leaflets are opposite along the main leaf. Here is a "big picture" of the whole plant, a picture of the sprouts on the left, stump on the right, and some better pictures of the leaves, with my hand and thumb for comparison. Hopefully this will help.

You have centipede in California? Is that a new trend since the drought? 99% of all the centipede is in Florida and still that's not very much centipede. It grows best in terrible soil with terrible care. It needs almost no fertilizer. People say that once every other year you can drag an empty fertilizer bag over it and that's enough. It loves the acidic soils like they have on the east coast. I would think St Augustine and bermuda would be the main go-to grasses in the Central Valley. Some water restrictions are fairly enlightened and some are guaranteed to kill everything if you follow them. Ours are horrible. We can water from 7am to 9am and 9pm to 11pm on one day per week. Well, who's around in the morning from 7-9??? You'd have to be retired. I suppose you could use timers (and I have a good one). But timers don't work for veggie gardens and plants located around the yard. That leaves 2 hours in the dark to get your watering done. In San Antonio we could water from midnight until 10am and from 8pm to midnight on your day. Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.