Hydrangeas are popular ornamental plants grown for their showy flowers. Hydrangea Ringspot Virus (HsRSV) and Hydrangea Chlorotic Mottle Virus (HdCMV) are plant pathogens that stunt and damage the growth of hydrangeas, which leads to strongly symptomatic plants being discarded. The viruses cause yellowing over the leaves in a ring or mottle pattern depending on the virus type. Symptoms are more pronounced under cooler temperatures, making it challenging to grow infected plants into bloom for sale in a cool greenhouse for Mother’s Day sales. HdCMV is spread by aphids, and both viruses are spread by cultural practices. The biggest problem is having propagation stock infected because once parent plants are infected the plants from cuttings from them will also be infected. This fact makes it apparent that there needs to be effective ways to clean and then maintain clean plants from infected plant stock to allow for a clean crop moving forward. In this experiment, meristems (small groups of ~20 microscopic cells at the uppermost tip of stems) from infected Endless Summer® Summer Crush Hydrangea plants were isolated and regenerated into plantlets in tissue culture. The youngest cells in the meristem typically are not infected with the virus yet and if they can be isolated, some of the plantlets may be clean of the virus. RT-PCR was used to test the 26 regenerated plantlets from unique meristem isolation events for these two RNA viruses, and specific primers for each virus from the University of Minnesota (U of MN) and South Korean researchers were trialed. Hydrangea Actin primers were used as an internal control to make sure the RT-PCR worked. Known positive and negative controls for each virus gave the predicted bands for the HdCMV primers from both the U of MN and South Korean researchers, while only the HdRSV primers from the U of MN worked. It was found that in all 26 cases that the plantlets from isolated meristems were clean of both viruses. This demonstrates that meristem isolation techniques used at UWRF are very effective in cleaning hydrangeas of these viruses. Clean plantlets of this popular hydrangea will be maintained in tissue culture and made available upon request from our industry partner.