Sandy McLeod, owner of Ripple Creek Nursery, said the precious trees were stolen from the Benoni Agricultural Holdings (BAH) nursery on April 30.
McLeod said her entire collection was stolen, which is valued at around R20 000.
The trees were for sale and were also pinched with 10 baskets of petunias.
Some of the species, which range from six to 20 years of age, include white stinkwood, Chinese maple, Chinese elm and junipers.
McLeod has now contacted local nurseries and nursery sales representatives to warn them not to buy the trees.
“It’s so sad this is happening as it takes many, many years to get them looking good and they are very valuable,” said McLeod.
“It would be good for the public to be aware that these (bonsai) are now sought-after by the dishonest people in our society.”
The nursery owner said she would open a case with the police soon.