Sunday, August 15, 2010

More About Our Weeds

by Jon Latimer

A neighbor in Parcel 7 made the following comment in response to my earlier posts on the poison ivy and weeds: “John, you appear to be quite upset with the landscape committee for their choice to not use chemical fertilizer last season. While the immediate state of the lawns or increased poison ivy are issues of concern, I find that the committee's efforts to rely on organic methods of weed control admirable. It is still desirable, in my opinion, to identify non-chemical means of control.”

The comment touches on some important points and merits a detailed response. To be clear, use of “chemical fertilizer” isn’t the issue. Fertilizer is used to promote the growth of desirable plants. Herbicide is used to prevent the growth of undesirable plants such as weeds and poison ivy. My posts on weeds and poison ivy questioned last year's decision not to use herbicides. It’s also important to distinguish between turf areas and exposed soil in berms or planting beds. Weeds can be a problem in both, but the methods of control are different.

In berms and planting beds, mulching is well recognized as a “non-chemical method of weed control.” The standard practice is to apply mulch in early spring before weeds emerge. Last year, except in one or two parcels, no mulch was used at Princeton Landing. This year, mulch was applied throughout the community, but that work didn’t start until late June and wasn’t finished until late July. By then, weeds and poison ivy were established well enough to simply push through the mulch and continue growing. Once that happens, they can only be removed by spot-spraying an herbicide such as Roundup or by pulling them manually. Spot-spraying herbicide is of course not a “non-chemical means of control.” Manual removal is much less thorough and less effective. It is also very labor intensive and therefore too costly for a community like ours, which has a large and complex landscape and already spends hundreds of thousands of dollars each year on landscape maintenance.

Mulching is also much more effective at suppressing weeds if a pre-emergent herbicide is applied to the soil before the mulch is put down. Indeed, Princeton Landing used this combination successfully every spring for years. We’re no longer doing so. In fact I understand that for budgetary reasons mulch will now be applied only every other year. If the goal is to rely more heavily on "non-chemical means of weed control" that's actually a step in the opposite direction. Needless to say, in the years when no mulch is put down, application of pre-emergent herbicide will be the only defense available against invasion of our berms and planting beds by weeds and poison ivy.

Turf areas present a different challenge. As I pointed out in my post, lawn areas throughout the community are now infested with weeds such as crabgrass and spurge. In the past these were controlled by applying pre-emergent and post-emergent chemical herbicides. Thickly growing turf grass helps sustain itself by “crowding out” weeds, so it's important to prevent weeds from becoming established. No herbicide was applied to the lawns last year. Weeds gained a foothold then, and came back with a vengeance when our turf went dormant in this summer’s dry heat. The ugly results are now visible throughout the community. Once weeds become well established in turf grass, the only “non-chemical means of control” I know of is to remove them manually. As I noted above, that is too labor intensive and too expensive for a community this size.

So although the commenter from Parcel 7 finds “the committee’s efforts to rely on organic methods of weed control admirable,” in fact no such “methods” have been explained and justified publicly to the community, and none are being practiced. Instead, a few poorly informed residents have led the Landscape Committee through a series of shortsighted and destructive misjudgments, against the advice of the community’s landscape professionals. Our landscape is now deteriorating at a frightening rate. It will take years of remediation to get it back to the condition it was in before. This should concern every homeowner because it has a direct impact on the beauty of our community and the value of our homes.

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