Simazine is a pre emergent. Just one that covers a broad range of weeds and is safe in food crops.

Now that we have a freeze I'm going to spray round up all over my yard

Is bermuda officially dormant after the first freeze?

Mowed for the last time until April
Bermuda and St Augustine are essentially dormant once we get night time temps in the 40s

Be careful, glyphosate kills any green leaf. If you still have some green blades of grass that could possibly still be growing, it will kill it.

I got a Red Oak in the front yard and the Bermuda isn't as thick as I would like under it. If I put out Lesco in mid February, when can I spread Bermuda seeds throughout the yard? Will Lesco affect the seeding?

I would wait at least 3 months. But you will be fighting a losing battle spreading Bermuda seed under an oak. Too much shade for Bermuda to do well. I don't know how big your oak is, but they grow an avg of 2'-3 foot a year. Times that by 10yrs and you will have a very large tree and lots of shade.

Thanks Derek. Yea its about 22 years old now.

Msma is always the answer

I look do a full sodding of the area with either the shade tolerant Zoysia or some St Augustine palmetto.

This and thin out some limbs allowing some filtered light to get through. If you put down sod, prep the area with 2 inches of good 50/50 or 60/40 compost. Better yet since you are close to Denton, go get a load of Dyno Dirt and spread before putting down sod.

My fall / winter / early spring weeds are doing good despite putting out the pre-emergent to prevent it. Guess I’ll wait until February and try again....

It's the weather, warm december

It is winter but yet we really haven't experienced winter weather yet

What pre-emergent did you put out and when? Follow up question. Did you water it in properly? Got mine out first week of Sept and virtually have no weeds. I have a little rescue grass around the mailbox and a couple dandelions that have tried to popup but that's it. Nothing is 100% but I'm looking good so far.