Our recent rain storms have been great to help move the salts through the soil, and provide our grass with the best kind of irrigation out there.  But it also means that we will start to see our weeds emerge from the ground. Not good if you want to have the best sodded lawn in California!

It’s a well known fact that the best defense against weeds is to have a good dense stand of grass.  If you have followed my previous tips and have been fertilizing on schedule, your lawn is likely thick, lush green and is in perfect shape to fight off weeds.  If you are a little behind on your fertilizer applications now is a great time to catch up.  You can use our “Seasonal Booster 7-7-7” to help thicken up your lawn and prevent the weeds from encroaching in the open areas.  It is very different to control weeds in lawns that are overseeded with ryegrass versus lawns that are left dormant for the winter.   I will touch on both.  It is always best to practice weed management by hand pulling weeds before using unnecessary herbicides.  If your lawn is being over taken with weeds or is too much to hand pick and you have to apply a  herbicide, ALWAYS ALWAYS READ THE LABEL FIRST, AND APPLY AS DIRECTED.  I cannot say this enough because it is very easy to injure your ryegrass or underlying bermudagrass by exceeding the label rates.

One of the problem weeds during the wet season is annual bluegrass or best known as “Poa annua.”  Poa is a high seed producing grass that likes compacted wet soils.  It often starts to show after a rain storm during the winter months and you will see the light yellow colored bunch weed growing with seed heads that multiply quickly.  Poa is a grass that can tolerate low mowing heights and wet soils so a good way to manage to manage the problem is to let your ryegrass grow longer, dry it out till your grass just about wilts and then water.

When you mow your lawn at a longer height it’s best to bag it as the seed heads will multiply if they are spread throughout your lawn from mulching it.  Here’s a picture of what Poa annua looks like.  If you do have Poa, there are very few chemicals that will treat it, and none are labeled for homeowner use.  The best way to control it is to keep it to a confined area and hand pick it out before it spreads.  

Broadleafs are significantly easier to control, and we’ll often see the emergence of such weeds as clover, mallow, and mustards during this time of the year.  These can be controlled with 2,4-D, Trichlorpyr or Clopyralid. These are easy weeds to control, and applying a pre-emergent herbicide is the best way to prevent them.

Crabgrass and goose grass are generally a result of a poor turfgrass canopy.  These are generally most active between February 15^th-March 1^st.   Some pre-emergents that work well to control these are Dimension and Barricade.  If you have crabgrass or goose grass take over sections of your lawn you will have to apply several applications of MSMA every 10 days for about a month or until it is controlled.  These are very noxious weeds that will find every possible gap in your lawn to take over so keep your lawn healthy and if you have large areas it is best to sod them out to keep the crabgrass and goose grass out.

If you have dormant bermudagrass it is advised to put down a pre-emergent herbicide such as Barricade or Dimension in late February to control weeds from encroaching in your lawn.  When your lawn is completely dormant you can control weeds by hand pulling them, using selective herbicides or –last resort–to use Round Up at a rate of .25 ounces per 1000 SF.  Don’t exceed this rate and do not apply to any areas that are showing signs of greening up.  If your lawn is starting to green up this may delay it or cause harm to the bermudagrass.  I do not suggest an application of Round Up after February 15^th.  Again READ THE LABEL, and always error on the side of caution.  If you are unsure if your lawn is completely dormant avoid the Round Up and use a selective herbicide.

These are just some of the main weeds we’ll start to see in the coming weeks, so stay on top of your lawn and keep it healthy.  If you have a weed that you are unsure of please send me pictures and I can tell you the best way to treat it.

 Jay