Career
In international play, she reached the quarter-finals at Wimbledon in 1966. She and Tom Okker reached the semi-finals of the Wimbledon mixed doubles in 1964. In 1967 she reached the final of the United States Indoors, where she lost to Billie Jean King 6–1, 6–0.
After marrying Christiaan Gerrit Walhof, she played under the name Trudy Walhof-Groenman.
Since 1987 she has been married to Marinus Anton Holboom. She currently lives in The Hague.
Groenman was a left-handed player, whose style was compared to Billie Jean King"son finals
Singles (2 runner-ups).