Yes you can store herbs for long term! Our products (www.firmeadowllc.com) are Best by generally two years from date of manufacture although we have had customers use products up to seven year old with favorable results (not recommended!).
The enemies to your herb blends are heat, greatly fluctuating temperatures, light, age and moisture so those are the situations we want to avoid for them. For herbs to be used within the next month or two often keeping them in their packaging and in a cupboard is sufficient. Herbs and blends that you will be keeping for longer than two months I suggest that one pull out a couple of months worth and keep that in the barn in a sealed freezer bag, lidded canning jar (be careful around concrete!), or a sealable plastic jar remembering to store it out of direct light. Also be sure to use a clean spoon or scoop and do not get any moisture into either container. The remainder can be kept in the original packaging in the house in a cabinet.
For those that want to store herbs beyond a year or two or for seasonally used products (like Ewe-Ter-N) I suggest you double bag the product you don't plan to be using that year and place it in the freezer. Most herbs as long as you didn't introduce moisture to them will keep for years in that manner.
If one is making an infusion (strong herbal tea) any excess can be kept for up to three days in the refrigerator. Excess can be frozen in ice cube trays and double freezer bagged for later use. I would use twice the amount for any cubes that I pulled from the freezer. Always put the current date on any bags of cubes.
For those making dosage balls with black strap molasses, organic peanut butter or raw honey which do not have a water content you can keep excess balls in the refrigerator for approximately a week. I would store them on a lower shelf since cold settles usually making that the coldest area of your fridge. Any that you'd like to keep longer than that double freezer bag and keep in your freezer. You may want to freeze them on a parchment paper covered cookie sheet before you bag them so they don't freeze together.
Herbs can also be stored indefinately in alcohol and for multiple years in raw organic apple cider vinegar and then straining the liquid before using. They can also be kept in olive oil this way for approximately two years. Remember to keep these out of light, to use sterilized containers and to label them with a date.