The talks form part of a programme about the inspiration of Henk Gerritson, Oudolf, and the designers and nurseries of the so-called Dutch Wave.
Two evening talks, one on 27 October with Jacqueline van der Kloet, and one on 28 with Tom Stuart-Smith, were sold out with hefty waiting lists.
Oudolf agreed to an extra slot in the afternoon of 27 October, with Tania Compton and Noel Kingsbury.
A talk on the afternoon of 28 will be shared with van der Kloet and Compton.
"What’s interesting is the chance to ask ‘What next?’ for the man who is probably the most influential designer in the world," said museum director Christopher Woodward.