St. John's wort experiences at Birnam Wood
Richard Arnott, Birnam Wood, Coolah, New South Wales 2843, Australia.
The property
The property Birnam Wood has an annual rainfall of 750 mm on lower parts and up to 800 mm on the high tableland. The soil is heavy basalt and it is steep country with an altitude of 610-1320 metres. It has been fertilized with gypsum, sulphur and sulphur fortified fertilizer (45% sulphur) since 1953 and so conditions are perfect for blackberry, briar and timber regrowth, which is in addition to a heavy infestation of St. John's wort.
Plant Protection Quarterly (1997) 12 (2) 99-100.