Hi Ranny,

You are one of many who are also dealing with these common but annoying types of weeds!  The picture you have included on the left appears to be Prostrate Spurge or Spotted Spurge and the one on the right is known as Common Purslane.

Both of these types of weeds are summer annuals we see in newly seeded or thinning lawns or in areas without much ground cover. You will also see these coming up through cracks in sidewalks.  

Both are easily pulled when the soil is moist, but make sure you wear gloves; both weeds produce a sap that can irritate the skin and causes rashes.

A Pre-emergent herbicide should be applied in the Spring to reduce or eliminate outbreaks, such as DCPA, dithiopyr, isoxaben, pendimethalin. Post-emergent herbicides are not very effective unless plants are young. 2, 4-D combination herbicides are more effective than 2, 4-D alone.  Also increasing your laws density with proper lawn care through watering, fertilizing and mowing (no shorter than 2.5 inches), will strengthen your lawn  and make it more resistant to weed outbreaks.

I have enclosed a few links to valuable information concerning weed control and lawn care, I hope they are helpful to you.   

• CSU Extension: Fact Sheet #7.202: Purslane:  www.ext.colostate.edu/pubs/garden/07202.html
  
• Plantalk Colorado:  #2110 Purslane:  http://www.ext.colostate.edu/ptlk/2110.html
  
• Better Lawn Care.Com: Prostrate Spurge: http://www.better-lawn-care.com/prostrate-spurge.html#axzz3k5Z1hUhv  
  
• Plantalk Colorado:  #2118 Herbicides: Pre-emergent: http://www.ext.colostate.edu/ptlk/2118.html
  

 Live Long and Prosper,

Liz U.

Weld County Colorado Master Gardener
525 North 15th Avenue
Exhibition Building, Island Grove Park
Greeley, CO 80631