This beautiful medium sized, slow growing tree grows very well in a well-drained loamy soil in full sun. It is a frost resistant plant. Syzygium legatii can be used as a container plant, ornamental plant because of the dark glossy green leaves and a shade tree for small gardens. It does not need pruning since its dense rounded canopy develops its rounded shape naturally and it does not need constant watering, although in some areas it grows along the river banks. When still young, watering can be done twice a week in summer, and once a week in winter. Slow-release and  organic fertilizer can be used to fertilize this plant. This plant species can be planted near paving since its root system is not aggressive and will not cause damage on the paving.

Syzygium legatii is easy to propagate by seeds. Collect the seeds when they are ripe and turn purple to black (April to May), clean the seeds by eating the fleshy cover, because is edible, the seed should not be dried because it has a viability for only one day after removing the flesh. Sow them when they are still fresh, in a well-drained soil, such as 1 part river sand and 3 parts potting soil. Place the seed tray under a shade net, water the seeds twice a week.

Germination will take place after two weeks and seedlings can be potted up when they have developed two sets of true leaves. Prepare planting bags and soil. Water the seedlings in the seed tray. Make a hole in the soil in a plastic bag using a dibber stick. Carefully prick out the seedling using a dibber stick. Plant the seedling in level with the soil surface inside the bag, firm the soil around the seedlings with your hands. Feed the seedlings with a slow-release fertilizer to kick start growth. Water the seedlings using a watering can and place them in a hardening off area for two weeks, while you are maintaining them. Move them under a shade net of 40% UV block.

In Australia, the most common diseases affecting species of Syzygium are caused by Pimple Psyllids, which are sap-sucking insects that prefer softer leaf surface that they can penetrate and cause galls on the leaves. At the Lowveld National Botanical Garden, Syzygium legatii is affected by Myrtle Rust fungal disease, fungicide is used to control the disease.