Dandelions are not on the list because there are two lists:

1. Stuff that is easy to kill.

2. Stuff that is difficult to kill.

Stuff that is easy to kill is the category of 'broadleaf weeds'. That includes clover, dandelions, and a dozen other weeds that are ugly ('canada thistle' and 'bull thistle' are a couple of my favorites). Weed B Gone kills these weeds. Get some Weed B Gone, and spray it around. Bingo. No weeds. This is SOOOO easy. Get your weed b gone, go spray it, and hey, no weeds. Done.

2. Group Two is the weeds that are difficult to kill. These are weeds that are really grass. Yep. They are grass. They are not a 'broad' leaf, they are a 'narrow' leaf, because they are a grass. You notice how clover, or plantain, or thistle, has a leaf that is wider than a blade of grass? I hate to say this, but they have a 'broad' leaf. They are not a blade of grass. All of these weeds will be killed by a 'broadleaf' (hey, they're not even trying to confuse us, yet) weed killer.

These 'narrow' leaf weeds are really a grass (or, if you want to get technical, one of them is a sedge. Pay no attention to this sentence).

You can't kill a grass with a broad leaf weed killer. No. Can't be done. So the scientists (both of them) got together, and decided that, since most grasses pop up from SEEDS, hey, we could create a chemical that KILLS SEEDS. It doesn't kill big, healthy plants, but it kills seeds. Before they (ready for this?) EMERGE from seed. And, Roy and Hal, decided that they would call their chemical a 'PRE-emerge' (or pre-emergent) weed killer. It kills those seeds before anything emerges from those seeds. And that would actually SOLVE the problem of 'what do we do about those hard-to-kill weeds that appear to be immune from broadleaf weed killer (because these weeds don't have broad leaves)?

Bravo! This has solved the problem, eh?

No. Not quite. The problem still remains that 'pre-emergent' weed killers (they should be called pre-emergent SEED killers) last for a month, or two, or three. They do not last for a year. They probably should, but they don't.

So here we are: if you have broadleaf weeds, spray weed b gone. If you need a pre-emergent, hey, put it down. It might even work. But there might be some leftover (undesirable) grasses. So we have to do it over again? Or is it that we have to do it at a different time of year? Or both? WAHHHH! Why can't this be easy?

Congratulations. Now you're right up there with the rest of us. Let us know how it turns out. Really. We need the advice as much as you do.

This is just a guess, but I thought I read somewhere that dandelions seed and start to grow in the spring from seeds dropped that spring, the plants continue to grow through the warm weather, overwinter, and then send up those big seed heads the following spring. Maybe because these seeds are not in the ground by the time the pre-emergents are applied, they are not affected by them? I really don't know, but I have been told to spray weed killer in fall to prevent them from seeding the following spring, and then do it again every fall after that to deal with all of the seeds that fly in every year from the neighboring weed farms.

Because dandelions are perennials,any existing ones will have to be wiped out with a broadleaf weed killer. You can use a pre-emergent such as Greenlights "Portrait" that contains Gallery,a pre-emergent that controls many broadleaf weeds including dandelions,chickweed,henbit,spurge,clover and oxalis.