New Weeds/Have Pics

[dricketts]

Last summer I had some new concrete work done. This required new top soil and grading for half of my well established yard and left mere dirt after all was done. I seeded heavily last fall with good results except for some nasty unfamiliar weeds that started appearing in mid March.

I live in Kansas City, MO and applied preemergent with fertilizer on March 1st this year. I've never had problems with these weeds in the past. I'm guessing they were introduced to my lawn from the new topsoil.

I'm hoping someone can help me identify, kill, and prevent them in the future.

Thanks!

[Marcos]

Last summer I had some new concrete work done. This required new top soil and grading for half of my well established yard and left mere dirt after all was done. I seeded heavily last fall with good results except for some nasty unfamiliar weeds that started appearing in mid March.

I live in Kansas City, MO and applied preemergent with fertilizer on March 1st this year. I've never had problems with these weeds in the past. I'm guessing they were introduced to my lawn from the new topsoil.

I'm hoping someone can help me identify, kill, and prevent them in the future.

Thanks!

The one on the bottom is definitely henbit, a member of the mint family.
Not sure of the top one, however.....but really, it's all a non-issue, because both weeds are obviously dicots, and can be controlled with the use of the same type of selective broadleaf herbicide.
I personally recommend that you spray JUST the areas affected with a hand tank, or as the pros call it, "integrated pest management". :)
You can even add a small bottle of kitchen (blue) food coloring to your spray mix to help to see exactly where you've sprayed, and where you haven't.

Weed seeds do exist in the soil, yes! :waving: Some species of plant seeds may lie dormant in the soil for up to 6-8 years.

But the primary reason why lawns develop weeds is because there always will be weak points here or there where the turf itself isn't established fully enough to naturally choke out potential weed competition by itself.
The homeowner, and/or the lawn care company they have hired has to to continue to keep focusing on improving turf density.

In other words, something like this: (spring)....rake, seed thin areas...(fall)...rake...seed...aerate...compost...(spring)...rake, seed thin areas...
Get the picture?

After some time, you may even find that you won't even need to buy crabgrass pre-emergents anymore, because your turf is too dense to allow crabgrass a foothold!

This was cultural control Weed Control 101 in a nutshell. :waving:

[pdenney11]

Bottom is Henbit

[pdenney11]

I think the top is Shepherd's Purse. Both are broadleaf so I suggest taking Marcos advice.

[dricketts]

Thanks guys.

Marcos, can you elaborate when you say "can be controlled with the use of the same type of selective broadleaf herbicide."

Are you referring to the pre-emergents or a weed killer that will kill them after germination?

[All Season Bill]

We all use a 'selective herbicide' which simply means it will kill the weeds but not your grass. But it can also kill flowers and plants...so don't spray in the beds.
Oh better yet...just call one of us....ha!

[Kiril]

Both can be controlled by hand pulling before they go to seed. That is IPM.

[cgaengineer]

Both can be controlled by hand pulling before they go to seed. That is IPM.

I'm sure this fellow has no idea what IPM is if he is asking what type of weeds those are.

To the op, the bottom pic is henbit and will die in the spring/summer. Your best bet is pre-m application in late summer/early fall and again in the winter to prevent these from coming up. You will have to read up on the timings of these applications or check with your local chemical supplier (Lesco, John Deere Landscapes or wherever you buy your chemicals)