How to use herbicides and what are they.

Glyphosate

Herbicides used commonly are taken in-absorbed through the plants leaves only!!
The most common is the non selective herbicide called glyphosate, this hugely diverse herbicide is found in roundup and most all variations, will kill near any and all plant life, but not hut grass!
This one that comes in many forms and all are called glyphosate, is made of acids or and salts and potentially other chemicals to convince the plant life to take in this concoction.
All the glyphosates components are naturally occurring, that is why it is relatively safe to use correctly in nature because it binds to the soil very quickly and is then neutralised via bacterial activities.
Of course nothing used in abundance is perfectly safe and a few people have died due to it being taken orally, but that was, as with many things consumed when they should not be, stupid or self harm!
This product can not affectively by taken in through our pores-skin, though with some people especially children, the acidic or salt make up will quite often cause annoying rashes.
It affects all animals in basically the same ways as humans.
It will be up taken by many forms of vegetables as they grow and it quite often enters our body with out us knowing, but it remains as glyphosate as it passes through very quickly and our body des not store it or use it.
There are other compounds used with glyphosate by varying companies, so its best to not let it get into us!
What it does is stops plants from manufacturing certain proteins stoping a very specific enzyme pathway called the shikimic pathway and they die, roots and all and become food for the other plants.
All plants are cannibals you might say, as the plant next door dies, the nutrients given off by bacterial degradation from that decaying plant, feeds them.
With grass as one example, grass clippings lightly spread over the other grass not smothering them, is the very best fertiliser for grass!
So mulch-mow your grass, most mowers have a mulching plug we call them to suit most mowers you can buy, so do not catch the clippings, it is extremely negative for over all scheme of things!

The best ways to use this product.
Do not use this product if the area is experiencing prolonged dry times, it will not work well, best is the day after rain or up to the following two weeks after rain and if it rains with in 2 to 4 hours after applying, it may wash off some, making the result a little weaker.
Use the correct mix ratio as prescribed on the bottle to do general praying and add a tiny bit of dishwashing liquid, it helps it remain on the leaves for longer and be careful when spraying if it is windy, this blows it away from the plants you are aiming for, any others that get over spray-drift will most likely die.
For spot herbiciding, like just that one type of plant or grass species, usually these ones are greater in height to other grasses-plants, so just use the herbicide with fifty percent water and fifty percent concentrated herbicide containing glyphosate with a drop or two of dishwashing liquid and use a fine bristle paint brush to touch-brush the offending plants leaves and it alone will die.
Toxicity information- http://npic.orst.edu/factsheets/glyphogen.html

Killing large trees or large weeds.
When using this product to kill plants of a size, it needs to enter the plants system with in 20 second to a max of 2 minutes after opening up the plant or the plants sap will seal up any chance of you getting the glyphosate into its body mass.
With large weeds, cut off the body of the weed and apply-brush on the straight to maybe a fifty-fifty mix of the herbicide with water to the top of the trunk and it will take in the herbicide killing it.
If you cut off a small or large tree, to stop it from regrowing,its bark line is the only area you need to apply the herbicide to quickly, the wood of a tree is with out life and will not take in the herbicide, this is the trees support and is not alive persay!
With a live large tree, go around the base making cuts into them just through to the wood as you make the cuts, then pore a small amount of glyphosate straight into those cuts as quick as possible.

Selective herbicides

Sempra
This one is made of mostly halosulfuron-methyl and is for nut grass.
With it mixed correctly, and it comes as tiny granules that mix with water quite quickly, it can be sprayed over pretty much any plants or grass or what ever and will only take out the nut grass!
Toxicity information- http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC32841

Fusilade
This one is for all couch grass species more then anything else is comprises of Fluazifop-P-butyl.
Spray it on broad leaf lawns in gardens or what ever and it only kills couch and kikuyu grass species.
Toxicity information- http://www.domyownpestcontrol.com/msds/Syngenta_Fusilade_II_6-9-15_MSDS.pdf

Kamba
This one is for all your broad leaf weeds including all forms of clovers and ones like bindii and more, but it will kill all of your broad leaf grass species like sir Walter, so be careful with this one, the ingredient dicamba is present as the dimethylamine salt which is the weak version of agent orange from its Vietnam fame as 2,4-D.
Toxicity information- http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC33374

Bin-die
This amgrow product is the ants pants for killing weeds in lawns!
Most other herbicides used to do this, ended up killing all the broad leaf grass species like buffalo species, bin-die works very well..

There are more versions of these selective herbicides, so if you use anything else, check on line carefully as to how it works and how nasty it can be to you and nature!