Can you take Ashwagandha while taking Risperon?

Yes, you can. There are no contraindications to the simultaneous use of the preparations mentioned in the question.

Please remember that all preparations containing Ashwagandha are dietary supplements and data on their effectiveness or safety are limited. Clinical studies have shown efficacy in the subjective perception of stress after 60 days of use. The dosage is also important, 240-600mg per day. These types of preparations will not work after 1 tablet, so it is too early to assess the effectiveness of the preparation.

I've included additional information that you may find helpful:
https://www.gdziepolek.pl/substancje/ashwagandha