Lawns Mowed Too Short Can Be Problem Areas for Weeds

 Q. For years I’ve had a problem with weeds in certain areas of my yard. They arise in July and continue during our humid monsoon season. Every spring I give my lawn a couple of doses of Scotts ‘Weed and Feed’. I’m tired of pulling weeds by hand. It’s very tedious work and I’m now up there in age.

Spotted spurge invades open areas that have lots of water. They are a small weed with small white sap that exudes from broken stems.

A. The weed you are talking about is called “spotted spurge” because of its dark spots on its   tiny leaves. It is a low growing spreading weed with a milky sap when you break their spindly and thin stems. It spreads quickly into unprotected areas and germinates from its own seed which it spews everywhere from its tiny flowers.

Spotted spurge invades an open area that is wet. It has "milky" white sap and spots on its leaves.

All spotted spurge are considered “weak competitors” when shaded by other plants or the soil is covered by a thick mulch, and quickly invades areas after a rain or during frequent irrigations.  In the desert it favors the frequent irrigations of lawns, flower beds, or raised vegetable beds.

Lawn grass with dead or dying areas should not be cleaned up until you are ready to plant grass seed in the fall or spring. Also raise the mower height and never mow the lawn below 2 1/2 inches tall if fescue.

Because it’s a weak competitor, spotted spurge is controlled by covering these open areas with three inches of a surface mulch or shading these same areas with other plants. The existing plants must be killed first and then immediately apply a preemergent weed killer to that attacks the seed before it germinates.

A thick layer of mulch helps to prevent many weeds from starting and becoming a problem. It doesn't help with common bermudagrass and other perennial weeds that are tough to get rid of.

To address your situation, first kill the existing plants. This can be done with a hoe, pulling them, or killing it with chemical such as Monterey’s ‘Spurge Power’ and then removing the plant by hand after it dies.

As soon as the existing plant is removed, immediately apply a preemergent weed barrier such as any chemical applied as a pre-emergent weed killer that controls crabgrass. The pre-emergent weed killers last about 30 days if left undisturbed.