Acetylsalicylic acid (Aspirin)
Salicylic acid is formed from salicin which is found in the bark of willow trees, as well as in the wildflower, Meadowsweet (Filipendula ulmaria). Extract from willow bark has been used to treat pain since the time of Hippocrates (around 400 BC). Medicinally, it can be used to treat aches and pains and topically, to treat acne.
The acetyl derivative, aspirin, is a non-steroidal anti-inflammatory drug widely used for pain relief and in the prevention of heart attacks and strokes. Estimates suggest a global usage of above 120 billion aspirin tablets per year.
While most of the chemicals highlighted in this trail have a primarily defence function in the plant, some are involved in other aspects of a plant's physiology, In Willow, the Acetylsalicyclic acid produced prevents the growth of other plants within the vicinty that would compete for resources, a phenomenon known as 'allelopathy'.
Willow is used to make cricket bats and is the Bach Flower Remedy for self-pity and resentment.
There are several very ornamental willows at the Botanic Garden - the bright coral stems of pollarded Salix alba 'Britzensis' contribute vibrant colour to the Winter Garden. Salix aeqyptica by the Lake produces velvet-soft catkins in early spring.