Weed with a passion, beds and lawn

How we weed the lawn depends on which weeds are there

If the weed is already growing, no use spending the money or risking the exposure to pre-emergent weedkillers (such as Trifluralin the active ingredient in Preen; naturally derived corn gluten meal isn't risky but is expensive). Two examples are perennial sour sorrel (Rumex acetosella) and"winter weeds" such as winter-germinating annual weed corn speedwell (Veronica arvensis). Pull them or dig them from the lawn or bed.

Just a note about timing of spring weedkiller application:

Sometimes spring comes late or early. Lawn care companies that operate only by calendar, i.e. "It's April 1, must be spring", may apply pre-emergent herbicide too early or too late. However, if the stuff is applied too early it will wash away before it can be effective, too late and it may be ineffective because the weed seeds have already germinated. (In addition, early application may mean people walk on your lawn while it's wet, compacting the soil and wrecking it!)

Pre-emergent herbicide should be applied based on soil temperature. Watch the shrubs in your neighborhood and when the forsythias bloom, the soil is warm enough to warrant crabgrass preventer.

Unfortunately, there are super weeds...

For those such as star of Bethlehem, we just keep at 'em.

Below, left: Corn speedwell (orange arrow) blooms with tiny blue flowers very early in spring. If you want to control it with pre-emergent chemicals the time to apply them is in fall.  Keep in mind that new grass seed (blue arrow) will also be killed by pre-emergents, so their use prohibits overseeding a thin lawn.
Below, right: Many gardeners know sour sorrel (most noticeable in a lawn in its cold-resisting purple-leaf stage) by its shallow but extensive, spidery thin and nearly elastic root system with sprouts from every bit that snaps and remains behind.

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We just loosened and overseeded patchy lawns

Lawns have suffered badly in recent hot, dry years. They're so thin there is a lot of room for weed seeds of all kinds to sprout, and where perennial weeds can bulk up.

Early spring is a good time to overseed. Once we coax the lawn back to thick growth it can crowd out its annual weeds and we'll know which spots remain where perennial weeds hold sway. We'll dig them out; an option is to spot-apply a post-emergent broadleaf weedkiller.

Bulb Star of Bethlehem a weedy curse

We wrote about a weedy bulb (star of Bethlehem, Ornithogalum umbellatum) in What's Coming Up #34.

In the telling of that tale, we touch on almost every aspect of weeding. We hope you don't have this weed and the closest you ever come to it is in these photos and excerpt from #34...

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