White Comfrey

Unlike its cousin, S. officinale, the flowers of this useful plant are pure white. It makes a wonderful fertiliser and, being semi-evergreen, leaves can be added to the compost heap throughout most of the year. It can also be used as a mulch and a liquid fertiliser can be made by steeping leaves in water for a while. A little invasive, but regular dead-heading will prevent this. Gardeners with plenty of space can cultivate a comfrey patch so that they have a constant supply.