My understanding is that there are 2 different formulations of Preem. What is the active ingredient in yours?

Henry, I just got the regular preen from Home Depot (not the organic one) https://www.homedepot.com/p/Preen-5-625-lbs-Garden-Weed-Preventer-24-63795/100609197 .

Jackie, thank you. That's very helpful. I will do the same. Thanks. Helen

Helen, thank you so much for this thread. I have to try this. I get so much if rain and everything springs up no matter how much of mulch I apply. Guess I am in capital of weeds World. I don't mind trying this also and see for myself.
jin

I'm not organic when it comes to lawn ....but everything else, I try to stay off the chems if I can. The weeds can't be that hard to pluck out in the beds are they ;-) Mulch helps a looong way, plus you get the side benefits of adding OM, moisture retention and what not.

Jin, we both can try it and share our experience here :)

a1an, pulling weeds isn’t hard if you don't have a lot of weeds and have a lot of time. However, I can only work on my garden some weekends so I need both preen and mulch to help combating the weeds. Helen

Never have used preen so I'll have to read up on it. If it's the same/similar effect on lawn, the critical path is the pre (before the seeds get going). I just do a very thin layer of mulch every year (just to keep the top looking fresh), but IME, as long as it's thick enough to choke out the light, things remain pretty weed free. Well, unless you got neighbors who let the weed grow into seeds and it's flying everywhere ;-)

I'm so glad someone asked! Thank you, Helen. Weeds are impossible to control here. I live in a rural area with open meadows and fields on every side. Wind blows the weed seeds in and it takes all season to pull them. I smother some with newspaper, compost and mulch where I can, but it's breezy all season, and they sprout on top of the newspapered areas. I've avoided Preen because I thought it would harm my plants. I'm eager to hear other's experiences with it.

a1an, lol you are talking about my neighborhood where weeds grow into seeds and flying everywhere :) I'm guilty of that sometimes when I have a lot of urgent projects at work. There are a couple seniors on my street who often let their weeds grows waist height in their yards because they are behind on their garden chores. I hope preen will help me keep up with the weeds.

floweraremusic, I don't have vegetables in my rose bed so I just bought the regular preen. I think I will use the organic preen for the areas near the fruit trees. Helen

If you are considering using the trifluralin based Preem product, please see:

https://www.houzz.com/discussions/4789638/is-there-a-weed-killer-that-is-safe-to-use-near-roses#n=30

Correction the brand is Preen, not Preem. Thank you, rifis.

I been pulling weeds like crazy. I am at a point that I am giving up on weeds. I don't know where this weeds are coming from . I have put cardboards, newspapers and tons and tons of mulch. It's been over a year and a half. Cards boards, newspapers and mulch is being broken down slowly and adding more layers but weeds are so, so invasive. They won't give up and they can pushed up and spread across the mulch. When I redo my beds....I find white roots everywhere...I know it is weeds and I go picking and picking. I need more help than that...as weather gets hotter and hotter and more humid. I am kinda giving up.
Even my Gardener wants to put something to kill the weeds in the beds and I said No. That tells you how bad it is here. I am so afraid of chemicals.....but if someone gets half of it down or 90 % down .....I am willing to try.
Where are this weeds coming from Cows manures ?? Some of this weeds, i have never seen in my backyard. I am even afraid to add cows manures Bec I feel as if it is loaded with seeds. It is never, Never ending battle.
I used claw hammer to dig the roots and yank the weeds out. The claw works beautifully and is my best friend.

jin

I like Henry’s idea of calling it Preem, evoking pre-emergent activity.

I didn't realize how ingrained my organic, no-spray ideologies were until just now, at the store, when I had Preen in my hand and couldn't put it in my cart. I didn't see an organic one. With every weed I pull, millions of little seeds burst onto the ground, so it's making a bigger problem by pulling them. Henry, I read your link and the links therein. Now, I'm even more afraid of using the stuff. I can not persuade my husband to stop using Round Up. He won't step foot in the garden with it, but uses it on the lawn and around the trees. I'm sure that's why my redbuds are dying and the Honey Locust is sparse. I don't need another chemical floating around in the air, so, I guess it'll continue to be newspapers, cardboard, mulch and hand pulling. They don't call it yard work for nothing.

The weed problem could make a case for planting very closely and densely. I love the look, but I need to see where I'm stepping because of snakes. I know we're not supposed to step inside garden beds, but my reach is not long enough to prune, deadhead and feed from outside the beds. Does anyone here use that method of weed control?

That's what I would like to do, but am not there yet. I, too, have an uncontrollable (at present) weed problem,but I do not want to use a chemical. Cardboard, cardboard, cardboard...

Good for you, Flowersaremusic! I admire you!

I use corn gluten meal. Preen has a version of it.

https://www.organolawn.com/blog/corn-gluten-meal-for-lawns

Thanks Henry. I think the reason I didn't buy the organic version because for some reasons the organic version listed as not available for sale in California, and ones have to order it online.

I looked up the review of the organic version and it works but ones have to apply a lot of it, which is ok because it will also act as fertilizer. I'll order the organic version from Amazon and return the regular one.

Here is an answer from the manufacturer regarding using it and transplanting:

How long do I need to wait to plant?

Answer: There is no waiting time required. Please be advised that during the 2 - 3 months the product is active in the soil, you do not want Preen granules to contact the roots of those plants as you place them in the transplant holes. We suggest you scrape the top layer of soil away from the area and dig the hole. Set the plant into the hole and backfill with untreated soil or a bagged garden soil. You may then distribute the treated soil you moved aside back around the plant . If Preen granules come in direct contact with plant roots, it can stunt the root development.

Helen

OP. If preen is like a pre-m, then disturbing the barrier when you transplant, I would top off the preen and when you water in the roses for the dirt to settle, you will also get the same job back of watering back in the Preen