Quick answer: Astrological botany assigned every plant to one of the seven planets. A herb's nature and medical use were read from its planetary ruler and its humoral qualities, the hot, cold, moist, and dry balance behind old medicine. Nicholas Culpeper's herbal of 1653 is the famous English key.
For the old herbalist, a plant was never just a plant. It carried the stamp of a planet, and to know that ruling planet was to know the herb's temperament, its virtues, and the hour to gather it. This practice is astrological botany, the green branch of medical astrology. Its most quotable voice is Culpeper, an angry young London apothecary.
Every Plant Under a Planet
The core idea was rulership. Each of the seven classical planets governed a family of plants that shared its quality: hot and fiery herbs belonged to Mars, cooling and soothing ones to the Moon and Venus, cold and binding roots to Saturn. To read a herb was to read its planet, and through the planet, its humoral action, whether it warmed, cooled, moistened, or dried the body. The same logic of celestial rulership runs through planetary dignities in the natal chart.
| Planet | Sample herbs (historical) | Quality and use in the old medicine |
|---|---|---|
| Sun | Chamomile, marigold, rosemary | Warming, strengthening, "cordial" |
| Moon | Willow, cabbage, cucumber | Cold and moist, cooling |
| Mercury | Lavender, fennel, valerian | Airy, for the mind and the breath |
| Venus | Rose, thyme, vervain | Gentle, warming, soothing |
| Mars | Nettle, garlic, mustard | Hot and dry, pungent, "cutting" |
| Jupiter | Sage, borage, dandelion | Temperate, cheering, "for the liver" |
| Saturn | Comfrey, hemlock, henbane | Cold, drying, binding, often toxic |
Culpeper's Rebellion
Nicholas Culpeper worked in London in the 1640s and 1650s, and he made enemies by printing medicine in plain English. He translated the physicians' Latin pharmacopoeia, their official list of drugs and recipes, so ordinary people could read it. Then in 1652 he wrote The English Physitian, the herbal reissued ever since as the Complete Herbal. For every plant he named its planetary ruler, and he worked by the doctrine of "sympathy and antipathy": treat a disease with a herb ruled by the planet that governs the diseased body part, or with one ruled by the planet opposite the one causing the harm. It was Galenic medicine, the mainstream medicine of the day, built on the four humors, with an astrologer's index added on top.
The Doctrine of Signatures
Alongside rulership ran the doctrine of signatures, the belief that a plant's appearance revealed its use. A walnut, shaped like a brain, was thought good for the head. A yellow flower was used for jaundice. The man-shaped root of the mandrake, shown in the picture above, marked it as a plant of strange power over the whole body. Renaissance writers such as Paracelsus and della Porta gave the idea its fullest form. It is symbolism, a way of reading meaning into a plant's form, rather than any real account of its chemistry.
Gathering by the Hour
Timing completed the craft. Herbalists gathered a plant during the day and planetary hour of its ruler, an old system that divided each day into hours, each governed in turn by one of the seven planets, and often at a chosen phase of the Moon, so the herb would be "at the height of its virtue." A Sun herb was cut on Sunday in a solar hour, a Saturn root on Saturday, following the same planetary days of the week that still name our calendar. In this way, the regimen of the body and the gathering of its remedies were kept in step with the sky.
Frequently Asked Questions
What is astrological botany?
It is the tradition of assigning each plant a planetary ruler and reading its medical virtues from that planet and its humoral qualities. A herb of Mars was hot and pungent, one of Saturn cold and binding. The herbalist matched plant to complaint through these rules of sympathy and antipathy.
Who was Nicholas Culpeper?
Culpeper was a seventeenth-century London apothecary who wrote a hugely popular English herbal in 1653. He listed the planetary ruler of every plant and translated the physicians' Latin texts into the common tongue. That combination made him both famous and controversial in his own day.
Is it safe to use these herbs?
No. Many plants named in the old herbals are toxic, hemlock, henbane, and mandrake among them, and they include some of the most poisonous plants in Europe. Astrological botany survives today as history and symbolism, a craft to read about rather than a working herbal.
Explore the Symbolism
To see the planetary rulers and elemental balance the old herbalists worked from, cast a free birth chart. Or read your own constitution through a health report, which draws on classical temperament rather than fortune-telling. For more traditional technique explained plainly, browse the blog.
