Light. Grows best in full sun but tolerates partial shade.
Water. Keep it watered until established; after that it needs almost no care. It will not grow in over-irrigated or constantly wet spots.
Soil and feeding. It does well in most soils, including clay, and is highly tolerant of alkaline soil. Its nutrient needs are low.
Size. Grows to 10 ft or more; mature trees reach 25–45 ft tall and 20–30 ft wide, at a moderate to fast rate.
Pruning. Needs little pruning unless you want to keep a set shape, such as a Christmas-tree form.
Problems to watch. It hosts cedar-apple rust, a disease of apples, hawthorns and pears, so avoid planting it near those. Male trees shed heavy, allergenic pollen.
Good to know. A Florida native that tolerates drought and salt, useful as a screen or windbreak. Female trees bear blue berry-like cones eaten by birds, and it hosts the juniper hairstreak butterfly.
Sources: UF/IFAS Gardening Solutions: Red Cedar · Natives for Your Neighborhood (Institute for Regional Conservation): Juniperus virginiana
