Dave, I think they they may be overused and are useful in a limited set of circumstances. A row of conifer screening happens to be one of those uses. Yes, the fabric (and I was only recommending a geotexile type, not a roll of impervious black plastic) will degrade. By the time it degrades completely, the conifers will have grown large enough that their shade will start to cut down on weed germination. In my observation, they undoubtedly increase soil moisture retention and reduce the need for watering. And in their first couple years, they do keep weeds down, which is the most crucial period for reducing weed competition as the plants are getting established. Later on, the few weeds that start growing in the mulch are easy to rake or pull out. I've had some in my landscape now for 5 years, all the plants around it have grown just fine, I've never had to water them in the past 3 droughty summers, and I expect in 5 years it will probably mostly degrade but by then it will be filled in with mature plants and there will be less light for weeds to grow. One size does not fit all and the article you posted has some good points, but I stand by my recommendation. BTW Ken's recommendation to not make a screen of a single plant type is good too.

Yes! Of course you are right. Pre-emergents go out before weeds emerge. The problem in our wacky climate is that weeds emerge erratically--very early in some years and not as early in others. The lawn care folks market more by "the calendar" than by what is really happening in people's lawns/gardens. Some (though certainly not all) are unscrupulous and will market products "out of season" just to sell the product, regardless of whether it will do anything for your lawn or garden at that point in time. I garden 98% organically (I will use Round-Up on bermuda grass but that's about all), but before I gardened organically, I knew quite a lot about pre-emergents and post-emergents. You know, you have to understand how they work if you're going to use them, so you aren't at the mercy of the "marketing" people and ad campaigns. Some gardening experts recommend that you apply pre-emergents at least 3 times a year: twice in the winter-spring time period, once in late winter to prevent those plants that emerge early/in cool weather and then later, in late spring, to prevent those plants that emerge in summer. The third application is usually recommended for early to mid-September to prevent the emergence of cool-season annual weeds (unless you are overseeding with rye or fescue and then you wouldn't use the pre-emergent). Would it hurt to use a pre-emergent now that you see cool-season weeds already sprouting? I doubt it. Since they don't all sprout at the same time, using a pre-emergent now will probably stop anything that hasn't already sprouted. If you decide to go ahead and use your pre-emergent after you've already seen the emergence of some weeds, please keep us all posted on whether you think it had any effect. That way, it will be a good learning experience for us all. By the way, there's a company out of Ardmore that is marketing "Red River Crabbgrass" as grass that is "excellent grazing, hay and land cover". I saw their ad in the March/April 2005 issue of "Hobby Farm" magazine". Clever idea on their part--turning their crabgrass into a business (ha!) but WHO IN THE WORLD would deliberately buy crabgrass? They can come to our place and dig up all they want for free!

No, no, no. Definitely not too late. Actually, if anything it was a little too early. The old wives tale about the forsythia is actually pretty accurate. If the Forsythia is in bloom it's time to put down the pre-emergent. If all the yellow leaves have dropped...its too late. It's all about soil temps and you have plenty of time.

Another vote for Prodiamine. It will seem expensive at first but then you realize how little you have to use. The amount you pay for Big Box store product will likely exceed what you pay for Prodiamine in the long run. In the past I used Halts with some effectiveness. However it seems with crabgrass, at least in my area, Prodiamine is more effective. It will also provide some broadleaf weed control as well.