I've been having a little problem in the landscape.   And the problem is with Paper Wasps.  They had built a nest that was about 6-8 inches in diameter....I did not have the courage to go up and actually measure it.  It seems like there were way too many of those guys surrounding it to do that and they seemed to come to full attention when they saw me coming.....First I found out that they are very beneficial and there are 22 species of them in North America and 300 species world wide.  And yes, all of them are certainly able to give you a nice sting  if they feel threatened or disturbed. 
 
Paper wasps are good wasps as they seek out caterpillars that can be eating our plants or flowers.   When found they sting and paralyze them and take them back to their nest and place them in individual cells as food for their developing larvae. 

The size of a Paper Wasp is between  ? to 1" long with a black and yellow patterned body.  Another name for the Paper Wasp is Umbrella Wasp as they make a nest that looks like an umbrella in shape.  And that is just what I saw in the landscape....a little umbrella with many busy wasps.  They didn't seem to worry about me at all....they just paid attention to what they were doing.

To make their nest they gather fibers from dead wood, fallen leaves or plant stems which they mix with their saliva.  The result is a water-resistant material that is either gray or a light brownish substance which they use to build strong nests in which to lay their eggs.  If in the wild some of these nests can be quite large.  The population of an nest is usually about 250 hornets.

When the young hatch out, they are fed with caterpillars and other small insects that may have been feeding on your plants.

So if you find one of their nests and it is not in an area where you will be frequenting ....just observe it.....but don't remove it.