Nobody likes annual bluegrass in their lawns, especially when it's seeding. It will stop producing seed heads soon in the NYC area, and it will fade away in the summer heat since it's an annual (unfortunately there are also perennial types, so all of it might not die off as expected). The problem is all those seedheads you see are dropping seeds in your lawn. They will lay dormant until late summer/early fall. When soil temps fall they will germinate but won't be very obvious. Then in early spring they will be the first to green up, and the cycle starts all over again. There are some specialty herbicides that can selectively kill poa annua, but it is a persistent weed. A good preemergent program over time should reduce most poa annua. Applications in late summer and early spring will kill most germinating seeds in your lawn, thus breaking poa's cycle. It will also affect any turfgrass seeds, so if you want to overseed you can't use preemergents months before seeding.

I'm trying to find a pre-emergent, with no luck. Can you suggest a brand name or a place that you think may sell it?

Taras, this is one topic that you need to focus only on answers that come from other New Yorkers. The laws about pre-emergents are very different in New York than other states, and even stricter on Long Island than the rest of NY. I know that your original profile says NYC and now says "10". I hope that you don't mean USDA Zone 10 - that's Southern Florida territory.

Finding appropriate pre-m's in NY is not easy this time of the year. Some garden centers have leftover "crabgrass preventers" that may or may not be right for this time of year. You can't apply a Pre-M in NY that doesn't contain a fertilizer. Look for Scott's Halts (NOT the "for seeding" stuff) or something with Dimension as the active ingredient (Dimension is not allowed on Long Island). I wound up with Jonathan Green crabgrass preventer with Dimension at a local garden center (I'm in the Hudson Valley). There are a few other active ingredients that are OK, but they are hard to find now.

Expect to get a lecture from some garden centers that the pre-m's don't work this time of year -- most garden centers assume that crabgrass preventers are only for crabgrass prevention (wrong!). Smile nicely and get the product.

Can anyone recommend or review "Hi-Yield Weed and Grass Stopper with Dimension Herbicide"? I saw it on-line and want to purchase it. Is mid March too early to apply it o my NYC lawn?

If you're looking to stop Annual Bluegrass (Poa Annua), it's not too early to treat with Dimension. It's too late. The majority of this year's Poa Annua germinated during last September. Dimension is a pre-emergent, so it will not kill already germinated Poa Annua, once it is more than a couple of weeks old.

BTW, in New York it is illegal to use Dimension that is not mixed with a fertilizer in the product.

OK, so I should wait until September and just put up with the spring time weed (it burns off with warmer weather)? Would putting it down now be a waste?
Thanks for the info; I will, of course, abide by any NYS law.

A product containing Dimension will control crabgrass as a pre-emergent if applied at the time that the Forsythia bloom. For Poa Annua, the time to apply it is between when the evening temperatures begin to first dip in late Summer (typically in NY the last part of August) and the beginning of September.

Please pardon my ignorance; when does Forsythia bloom. I believe it's in spring time? So, if I put down Dimension in the spring, I'll still get the Poa Annua this year but my crabgrass will be controlled? Then I can put down more dimension in early September for next years Poa? If done in Spring and the end of summer every year, my lawn will be nicer?

Forsythia is a yellow-flowered shrub that blooms in the Spring when the soil and air temperatures hit a certain level. The timing of when they bloom (and NOT the calendar) is the best indication of when the time is right for Spring pre-emergents to control crabgrass germination.

Will your lawn be "better" if you control crabgrass and Poa Annua? It will if you have had crabgrass and Poa Annua. It has no other properties to improve the lawn other than to prevent the germination of those.

I have a very small lawn, maybe 30' x 35'. If I can control the poa with pre-emergents, and as bonus it also kills the crabgrass, than I'll go that route. Because of the small area any other weed problem becomes easily controlled by digging out the offender. Thanks for all the advice.