One of Bach's second 19 remedies.
Prepared by the boiling method.
Those who are liable to times of gloom, or even despair, as though a cold dark cloud overshadowed them and hid the light and the joy of life. It may not be possible to give any reason or explanation for such attacks.
Twelve Healers 1936
In all things cheerfulness should be encouraged, and we should refuse to be oppressed by doubt and depression, but remember that such are not of ourselves, for our Souls know only joy and happiness.
Collected Writings p151
Mustard is most commonly found on the verges of new roads. It avoids acid soils.
Mustard is a common weed on arable land throughout Britain causing considerable problems for farmers; consequently it is being cut, sprayed and generally attacked. But since it reappears every time the soil is disturbed it is not too difficult to find.
For depression that comes for no apparent reason from an unknown cause, gloom, deep sadness, melancholy, usually serious people who feel that they suffer periodic affliction from a malefic star. Depression is intense and cannot be alleviated until it lifts as unexpectedly as it came. All joy and peace is driven out of life for the duration.
Barnard, Guide to Bach Flower Remedies