When all is right in the world, it’s easy to mess around with kitchen witching. That’s not the case when we can’t sleep, or the kid’s sick and screaming, or whatever the current herbal crisis happens to be. Over many years of drying herbs to infuse in honey “when I get to it” and not pressing tinctures until I actually have to use them (because farm life is just that kind of busy), I’ve learned that when I need medicine NOW, having to make it is a huge hurdle. Although I’m not as on top of my home apothecary maintenance as I’d like to be, I’ve made it a point to have a few basics in stock all the time, so I don’t have to make it in a pinch.
Here’s a recipe for a cold and flu tea to have on hand going into winter. This formula works well as a base, since it’s a general respiratory infection and get-well-soon mix. If you’ve got other symptoms, it’s a lot easier to add some willow and a sprinkle of angelica than starting from the top when you’re hacking up a lung. 
Although there are lots of great immune herbs from around the world, we’ve got what we need right here in our own backyards. If bioregionalism is a new concept for you, please see this article, but I’ll spare everyone else the rant repeat. These herbs are native or naturalized guests that flourish in cold climates, but if they won’t grow where you do, get out your books and talk to your neighbors to find a similar herb that does. For info on drying your own tea, see this article.
As well as bioregionalism, a couple of other concepts that come into play with formulation are synergy, balance, and energetics; if you’re interested in getting awesome at formulation, read up on those here, here, and here, but it’s too much for right now; hopefully in the future I’ll write an article or several just on formulation, but today is not that day.
Crumble together in a quart jar or airtight bag, 1 cup each of the following:
Monarda: Monarda fistulosa and M. didyma, with their many common names (bee balm, wild bergamot, oswego tea, scarlet monarda etc.) have thousands of years of traditional use in North America for cold, flu, fever, respiratory infection, and other permutations of winter illness.
Monarda didyma
I use them together, as I have found them to have a synergistic effect on stimulating the respiratory tract and “burning off” a fever (as Matthew Wood calls it), but you can use whichever species is local to you. Monarda is very useful as a warming (and later cooling, if you sweat out a fever), drying, stimulating, dispersing agent of change throughout the respiratory tract and sinuses. It will move out whatever cold garbage is stuck in your lungs, dry up a drippy nose, act as an anti-inflammatory and decongestant to sinuses (postnasal drip, headache with facial soreness, weird ear pressure), and sweat out a fever. It is antimicrobial, gently immune-boosting, and improves the mood.
Elderberry is one of the best-known immune stimulators and antimicrobials. It’s used daily to prevent sickness, and is wonderful in higher doses to help you get better, faster; the science is very good on this, numerous studies indicating some very high power T-cell stimulating scary-antigen-annihilating magic. I put it in almost everything immune-related because it’s so effective and delicious. Generally, you want to decoct elderberries and add them to the rest of the tea, but making separate batches kind of defeats the purpose of having a lazy sick person blend ready to go, so here’s a little cheat: dry elderberries thoroughly, then grind them in a mortar and pestle or grinder. They won’t last long, and they won’t be as strong, but they’ll get you through when you need them to, and you can infuse them with everything else if you have to. The herbal demagogues will frown at this advice, but I’ve found that there are a lot of folks out there infusing roots and berries as a matter of convenience—but at least grind them first so you actually get some medicine out.
Add ½ cup each of the following and mix well:
Hyssop is a warming, drying, stimulating fix-all for respiratory woes, sinus issues, and fevers. It’s antiviral and has a powerful effect on moving out deep-set, chronic conditions of cold-stuckness, especially accompanied by low-grade fever, thready pulse, and feeling sad or down. It has a synergistic effect with monarda in terms of flavors, energetics, and physiological effect. If you can’t grow hyssop, try elder flower. 
Lemon balm is a delicious antiviral famous for soothing frazzled anxiety, sleeplessness, mild pain, and imparting a feeling of general well-being. It’s effective against viral infections, soothes dry-behind-the-eyes exhaustion, and improves mood. It’s cooling, calming, and soothing, helping to ground excess energy to focus on rest and healing.
Thyme is a vigorous antimicrobial immune stimulant. It’s full of volatile oils that evaporate when dried, so it’s most powerful infused fresh into honey or syrup. That said, it’s still a very useful addition to tea in its gentler dried form. Thyme is very warming and moving to stuck secretions as an expectorant and decongestant, will help break a fever, and brings the antiviral magic right where it needs to be by stimulating circulation.
Add ½ cup of ONE of the following:
If you tend towards cold, stuck, inflamed, phlegmy (productive or nonproductive) congestion, especially with loss of appetite, facial pain, or sore throat that needs to be cleared:
Elecampane is a warming, stimulating respiratory decongestant, a mover and shaker that brings blood flow to the lungs, throat, and face and puts lots of power behind ejecting any disgusting slimy business stuck in there. This is strong medicine. It’s a root, so like elderberry it’s normally decocted. Keep it separate and decoct with the elderberry, or use this lazy sick person cheat: chop it up as fine as you can when it’s fresh, dry thoroughly, then grind and add to your tea blend. It doesn’t need to be powder, tiny shards of root will infuse if necessary.
If you tend towards dry, spasmy congestion, especially with painfully dry hacking cough, blood when you blow your nose, dry sore throat, eye soreness, and unequal ear pressure:
Mullein or violet leaf: These are both moistening herbs that cool, soothe, and heal dry inflamed tissues, especially the lungs, nose, and sinuses. Make sure to accompany them with honey.
Mullein, borage, and holy basil are all wonderful water-soluble herbs
If you always get sick this way, consider using a full cup (you can take out the thyme, if you need space in the jar).
Make your tea by adding 1-2 tablespoons per cup of boiled water, cover, and steep for 10-20 minutes.
Based on symptoms, add appropriate things to your tea like:
Honey is antimicrobial, immune stimulating, anti-inflammatory, and very soothing. It should be added to all tea made for someone who isn’t feeling well.
Immune-boosting tinctures like Echinacea, spilanthes, Oregon grape, yellow root, Japanese barberry (this is invasive so use a ton!) help you get better faster. 
However, don’t add these herbs dried to your tea, use them as tinctures: their magic is primarily alcohol-soluble, so the medicine is found in tincture, not tea.
Fever tinctures like willow, boneset, meadowsweet, catnip for kids, especially when accompanied by sore muscles and headache. These herbs don’t have to be in tincture form, but it’s easier in the moment—however, feel free to decoct/infuse to your heart’s content.
Cherry tincture (or decoction, syrup, honey) as a cough suppressant, for hacking coughs accompanied by muscle pain, when you just need it to stop.
Mushroom ice cubes: medicinal mushrooms are wonderful for the immune system, but they really lose their oomph when dried. My favorite way to prepare them is to make a 3-day decoction, freeze in ice cube trays, and add cubes to tea and soup when we’re sick. There’s a recipe for this on its way this week.
There are a million other awesome immune herbs local to your area, so have fun playing around with this and let me know how it goes. Have a nice winter!