Mullein (Verbascum thapsus)

Hyssop (Hyssopus officinalis) is a semi-evergreen shrub growing up to about 2 ft (60 cm), with narrow leaves and clusters of bright blue, two-lipped flowers. Known since ancient times as a “cure-all” for respiratory ailments, it clears congested phlegm and supports recovery from infections. Hyssop also has antiseptic qualities beneficial for cuts, abrasions, and insect bites.

Coltsfoot is a perennial herb growing to 12 inches with flowering stems covered in purple scales, yellow-gold flowers, and heart-shaped leaves. Indigenous to Europe and northern Asia and naturalized in North America, it is commonly found along roadsides, on verges, and in open areas. The flowers are gathered in late winter, and the leaves in summer. For at least 2,500 years, coltsfoot has been taken as a cough remedy and smoked to ease breathing. The Greek physician Dioscorides in the 1st century CE recommended it for dry coughs and 'for those who are unable to breathe except standing upright.'

Eucalyptus, a traditional Aboriginal remedy, is a powerful antiseptic used all over the world for relieving coughs and colds, sore throats, and other infections. It is warming and stimulating, and for many people its scent conjures up days spent in bed during childhood with eucalyptus and other oils smothered on the chest. Eucalpytus is a common ingredient in many over-the-counter cold remedies.

Osha is a powerful respiratory remedy that has been overharvested in the wild and is extremely difficult to cultivate. It is listed on the United Plant Savers at-risk list. The root has been traditionally valued for its ability to stimulate the digestive and immune systems while expelling mucus. Until wild populations stabilize, its use should be limited, with alternatives like pine, grindelia, and ginger recommended as replacements.

American spikenard (Aralia racemosa) is a tall, aromatic perennial bush up to about 6½ ft (2 m), with fleshy roots, large compound leaves, and clusters of greenish-white flowers followed by red or purple berries. Known for its warming, expectorant properties, spikenard is a tonic for weak or congested lungs.

Sweet violet is a creeping perennial growing to 6 inches tall with toothed oval leaves and attractive violet-blue or white flowers with a five-petaled corolla. Native to much of Europe and Asia, it is a common wayside plant also found along roadsides and in woodlands. In classical mythology, sweet violet was associated with death, but classical physicians recognized it as an effective emetic and cough remedy. The 17th-century herbalist Nicholas Culpeper noted that violets are cooling and moistening when fresh and green.

Andrographis, commonly known as Green Chiretta or King of Bitters, is an upright annual herb reaching approximately 3 feet in height. Native to India and cultivated throughout northern regions of India and China, this bitter medicinal plant has been valued in Ayurvedic and traditional Chinese medicine for centuries. Historically used primarily for liver support and treating infections - especially malaria - it has earned recognition for its powerful immune-boosting and protective properties. The plant thrives on plains and in forest undergrowth, where its spotted pale brown or purple flowers and long seed capsules distinguish it from other medicinal herbs.

Astragalus (Astragalus membranaceus), known in China as huang qi, is a perennial reaching about 16 in (40 cm), with hairy stems and compound leaves composed of multiple leaflet pairs. In traditional Chinese medicine, it is a sweet, slightly warming herb often used to boost energy, strengthen immunity, and support overall vitality. Modern research suggests it may benefit heart function, kidney health, and immune response.