Water Catharanthus coriaceus thoroughly when the top 2-3 cm of soil feels dry. Avoid overwatering, as this can lead to root rot. Allow the soil to dry slightly between waterings. Reduce watering in cooler months when the plant's growth slows.

Prune Catharanthus coriaceus to maintain its shape and encourage bushier growth. Pinch back the tips of stems regularly, especially in spring. Remove any dead or leggy stems to promote new flowering. Heavy pruning can be done in late winter or early spring before new growth begins.

Propagate Catharanthus coriaceus from stem cuttings taken in spring or summer. Select healthy, non-flowering stems and cut them to about 10-15 cm long. Remove lower leaves and insert the cuttings into a well-draining potting mix. Keep moist and warm until roots form.

Repot Catharanthus coriaceus every 1-2 years, or when it becomes root-bound. Use a well-draining potting mix. Repot in spring before the active growing season begins. Choose a pot that is only slightly larger than the current one to avoid excess moisture retention.