I have tons of these around my backyard...what kinds are they and how do i kill them?
#1 -- Lamium purpureum, dead nettle
#2 -- Geranium, probably G.robertianum
#4 -- Trifolium sp., clover
How do I kill them??? for good
1. Lamium purpureum, dead nettle, aka henbit.
2. One of the geraniums.
Mow your grass as high as the mower will allow which will aid in shading the soil so the seeds from these will not easily germinate and the grass will grow in thicker and crowd them out. Have a good soil test done because they al grow best in soils that are not that conducive to good turf grass growth, but at the same time the clover will supply Nitrogen to the soil that will help your turf grass grow better.
If you choose to use a poison use it with care and only spot treat as necessary. Do not buy something to cover the whole area and where these are not growing which is a waste of your time, energy, and money.
# 3 looks like young (pre-flower) Garden Yellowrocket (Barbarea vulgaris). See this site for more info
Dig 'em out and keep going. A biennial, it is easier to master than many other weeds.