Little Bittercress aka Shotweed

This is the most obnoxious and ever-present weed that infested my yard last summer. The situation was so bad that even my neighbor complained about the infestation in the front yard. Apparently this weed was shooting ( source of its common name - shotweed) its seeds into her yard.
Shotweed is an annual species of the mustard family growing to 5-7 inches usually, but I have seen it grow up to 12 inches long in shaded areas. It bears tiny white flowers and the resulting fruit is a long slender seed filled pod. A fully matured and dry pod explodes even with a slightest touch spreading the seeds up to a couple of yards in all directions. I have seen it grow anywhere and anytime. I spent most of my last summer fighting this weed to the extent that I had nightmares about it. I even saw vivid images of the leaves and the pods in my sleep. I had to meticuluosly hand pick the seedlings and the mature plants while trying not to trigger the pods. This time around it seems to be under control, but I do see it here and there. Mulching helps with shotweed control or use broad leaf herbicide if it gets out of control. Here is a link to a shotweed pdf document from Washington State University for more details.

Dandelion

Dandelion is probably the most dreaded weed out there. It derives its name from a French phrase ("Dent de Lion"), which means "Lion's Teeth" referring to the saw-shaped leaves. If uncontrolled it can turn your landscape into a dandelion crop. Dandelion control or elimination is very hard without a chemical weed killer or a good weed plucker that can systematically pull out all the roots. Nevertheless, the flowers look beautiful and are even edible. I have never tried it myself but here is a recipe for a "Summer Dandelion Salad".

Once the flower dries the seeds become airborne with the help of their parachutes.

Azalea

Azalea is a plant of the rhododendron genus. It flowers in mid spring and bloom pretty much entirely covers the plant. Needs very little attention except for annual azalea food and watering during hot summer days.