A common name can send a gardener to the wrong care page. Nandina sold as sacred bamboo should be identified as nandina before you choose a planting position or pruning method.
Keep the cultivar name too. Plants sold under the same familiar name can differ in mature size and appearance, which matters in a small border or container.
Check the role in the planting
Do you need a compact pot specimen, a background shrub or a plant beside a path? Compare the expected dimensions with the space available instead of assuming the small nursery plant will stay that size.
For an established nandina, inspect the stems and canopy before shaping it. Use guidance suited to the identified plant and the amount of work required; a bamboo name is not a pruning instruction.
Record position, watering and any recent changes if the foliage deteriorates. Seasonal colour, damaged leaves and declining growth are different observations. A clear identity and a dated photograph make them easier to discuss. Start with what the plant is, then decide what you want it to do in the garden.
NC Extension places Nandina domestica in the barberry family, not the grass family of true bamboos. It also lists the species as invasive in North Carolina. Check local guidance before outdoor planting; that regional listing is not a claim about every country.
Related reading: Nandina Care: Soil, Watering, Light and Pruning.