Cough Remedies
A tea of mullein - great lung herb, should always be in a mixture for the lungs, helps stop coughing when the lungs are infected or inflamed, but lets you cough if you need to
Osha - by far the best herb for the throat, with upper respiratory properties also. Unfortunately, the ingredients are not very water soluble, so you'll have to add tincture.
An expectorant with a light hand - not too much Coltsfoot or Horehound, it may make you cough too much. Perhaps something soothing and tasty like licorice, or even Hibiscus, or if by chance you have fresh lemon grass growing in your yard (don't we all?), use that too.
Perhaps even some calming herb like skullcap or a yummy Pedicularis. After all, these herbs are for spasms ... and coughing is bronchial spasms.
After straining, add an equal amount (or more) by volume of honey. This won't satisfy the US Dept. of Agriculture's definition of syrup (65% soluble sweetener I believe), but it does just fine, and is plenty sweet. Store in the refrigerator.
And go ahead and add that Yarrow if you want, but don't boil., just steep.
 

Cough Syrup
4 Cups Water
4 Tablespoons Liquorice Root
1 Tablespoon Thyme
1 Tablespoon Peppermint
1 Tablespoon Ginger
3 Cloves
2 Star Anise
1 Cup Honey
1/2 Teaspoon Lemon Zest
Juice of 2 Lemons
Spirits
Add the ingredients to the water and bring to a slow boil. Place a lid on the pot and let to simmer for 20-30 minutes. Strain the water into another pot with cheesecloth and bring to a boil, reducing the liquid to two cups. Add the juice of the lemons and the honey. Simmer for a few minutes, blending in the honey and lemon juice. Add vodka or brandy to taste and then pour into jars and let the syrup cool. 
 

For colds and sore throat
Make a tea from the following
1/2 teaspoon orange rind
a touch of cinnamon
3 - 4 eucalyptus leaves
1 teaspoon honey
 

FOR A HACKING, IRRITATING COUGH
1 oz. Ipecacuan syrup
1 oz. Sassafras (bruised)
2 oz. Aniseed
4 oz. Honey
2 oz. American Valerian
2 oz. Black Oats
2 quarts of water
1) Boil for 30 min.
2) Add 1 pint of spirits of wine
Dose: 1/2 wineglassful when cough is at its worse.
 

Home Made Cough Syrup
Ingredients:
16 ounces of whiskey
32 ounces of honey
08 ounces of lemon juice
16 ounces of hard peppermint candy
Melt the peppermint candy in 2 to 3 tablespoons of water. Mix all of the ingredients together in a simmering pan, stirring often. While you are stirring and mixing the ingredients visualize the healing power of the Goddess flowing through you and into the cough syrup. After the cough syrup has obtained a consistent texture then take it off of the heat and let it cool. Administer 1 to 2 tablespoons every 3 to 4 hours. http://www.nobleknights.com/~eagle1/cs-01.htm
 

Horehound Cough Drops
Simmer 1 cup of horehound leaves and 1 tablespoon of balm of gilead (you can indeed skip this ingredient) in 1 pint of water for about 15 minutes. Strain and add 2 cups of sugar. Boil until the mixture spins a thread as it comes off of the spoon. Drop by the teaspoonful into cold water to form the cough drops. remove the cough drops from the water immediately. You can roll the cough drops in powdered sugar after draining off the water. This will keep them from sticking to each other. Place is a tightly sealed container.
 

Liniment for Colds and Chest Tightness
Add 1 cup of finely chopped garlic to 1 cup of boiling lard. Reduce heat to simmer and cook for 2 hours. Remove from heat and strain the garlic fro the oil. Place in a container with a tight-fitting lid.
 

Parsley Cough Remedy
Relieves particularly persistent and stubborn coughs. Pour 2 1/2 cups of boiling water over 2 tablespoons of dried agrimony flowers or leaves and 1 tablespoon of dried parsley. Leave to infuse and cool. Strain into a stoppered jar or bottle. Take 2 or 3 spoonfuls at a time, morning and evening, and when the cough attacks. The remedy is especially effective if also used as a gargle twice a day.
 

Rose Hip Syrup
This is best made after the frost has come .
4 c crushed rose hips
water
4 T sugar
1 T honey
Boil 5 cups water , add rose hips and remove from heat. Steep 20 minutes, strain and reserve the fluid.Boil the strained pulp again in 2 cups of water. Remove from stove and steep 10 minutes. Strain and combien with the first liquid. Boil the liquid till it reduces in volume by half; add sugar and boil 5 minutes more. Remove from heat and add honey as it cools. Store in glass containers in refrigerator for up to 3 months.
 

Rosemary Tincture
This tincture is good to take internally to prevent colds or to fight infections. Because of the antibiotic nature of this tincture, it is also good to use to clean cuts and scrapes. It removes bacteria and prevents infections. Add 4 ounces of rosemary needles to 1 pint of vodka and allow to sit for 2 weeks. Strain and use a half a dropperful every 2 hours for a couple of days. Then cut back to 2 times daily for about 2 weeks to treat infections and colds.
 

Spruce Tea for coughs
by Bob Brenner
Ingredients:
Equal volumes of:
New growth from the tips of spruce branches
Water
Preparation:
Due to allergies, I am plagued with chronic, although mild post nasal drip and the consequential cough. I'd read in a local ethnobotany publication that tea from the new growth at the tips of spruce branches was used by the original people here for soothing coughs. I was hiking in the mountains and when I stopped to rest, I recalled that article as I was looking at a huge spruce tree.
I gathered a handful of the new tips and put them in an oversized enamel cup 2/3 full of water and set it next to a small cookfire to get hot. (Incidentally, I didn't remember about using the new growth until I tried to pull off a mature twig. Those prickles kinda brought tears to my eyes.) After about 15 minutes, I tried a sip and found it to be bland tasting and a little stinky, not pitchy smelling like I expected. I finished it anyway because it was warm and the weather wasn't. I wasn't impressed.
Note: I put out the fire and moved on. About a half hour later it occurred to me that I hadn't been coughing and didn't again for a couple of more hours. The tea doesn't give that menthol or eucalytpus tingle like I've been taught by the Vick's company to expect but for me, it works much better.