Water Petunia altiplana regularly, keeping the soil consistently moist but not waterlogged. Allow the top inch of soil to dry out slightly between waterings. Reduce watering in cooler months.

Overwatering can lead to root rot, while underwatering causes wilting and reduced flowering.

Deadhead spent flowers regularly to promote continuous blooming and maintain a tidy appearance. Pinch back stems occasionally to encourage bushier growth.

Prune back leggy stems in late summer to revitalize the plant and prepare it for cooler weather.

Petunia altiplana can be propagated from seeds sown indoors in late winter or early spring. Cuttings can also be taken from healthy stems in late spring or early summer and rooted in moist soil or water.

Repot Petunia altiplana annually or bi-annually, preferably in spring before new growth begins. Choose a pot that is slightly larger than the current one, ensuring it has adequate drainage holes.

Use a well-draining potting mix.