When do you sweep the grave in western culture?

I am a westerner and I have never heard anybody say they were going to "sweep" a grave. We do visit loved ones' graves but the frequency varies from person to person and there is no set day that we do it, except for Memorial Day and Veterans Day when people visit the graves of their loved ones who served in the armed forces (Army, Navy, Marines, Coast Guard).
Usually, grave sites are usually cared for by bringing fresh flowers, and also sentimental items like balloons and toys although some cemeteries don't allow those, and by trimming the grass neatly and taking away the dead flowers and leaves, which not everyone has to do, because the cemetery people normally mow the grass and take away any debris. We don't customarily bring food items. We do pray at the grave site but silently. Often there is a chapel on the cemetery grounds, and one can go inside and pray there if desired. Sometimes if the dead person was Catholic, a priest can be asked to say a mass for their soul.

I find cultural death customs fascinating, and I hope this helps!