Star Magnolia Guide: How to Grow and Care for Star Magnolias

A star magnolia (Magnolia stellata) is a large, rounded shrub or small tree with dark green leaves and fragrant flowers composed of over a dozen white, ribbon-like petals. Native to Japan, star magnolias receive their common name from the shape of their flowers and have low branches and close-set stems.

This tree’s flowers bloom in early spring ahead of other spring flowers, typically in early March. These deciduous trees also have a good tolerance for heat and the cold, making them perfect for USDA Hardiness Zones 4–9. Star magnolia trees can grow to a mature height of up to 20 feet and have a spread of up to 15 feet.

The blooms of star magnolia cultivars offer a variety of flower colors, ranging from white flowers with a pink tinge (‘Centennial’) to pink flowers that fade to white (‘Rosea’) to pink buds with white flowers (‘Royal Star’).

These showy, flowering trees are relatively easy to plant by following these simple steps:

• Choose your tree. Purchase a healthy, young tree. The tree can come in a container, balled, or burlapped but should be robust and without signs of damage.
• Find a location. Plant your star magnolia in a spot where it will be exposed to the morning sun but afforded filtered, partial shade in the afternoon. Flowers will bloom earlier the more light the location receives. While your tree can do well in a small space, giving it plenty of room to spread will keep it healthier. A location with some shelter will also help protect your star magnolia against late-spring frosts.
• Dig a hole. Ensure the hole is at least three times the width of the root ball or the container of your tree. The hole should be the same depth as the root ball or container, with the root ball sitting even with the ground when you place it in the hole.
• Plant your tree. Before filling the hole, make sure the tree is straight. Fill the hole halfway with the soil you took from the hole. Fill the rest of the hole with water, allowing the root ball to absorb the water. Then, backfill the hole with the rest of the soil.

Consider these elements of growing a star magnolia to help yours thrive in the conditions it needs:

• Growth rate: These trees can grow anywhere from 13 inches to over 24 inches per year. The habit (the general appearance and growth form) of the star magnolia is an upright conical crown that spreads somewhat with age.
• Mulch: Adding three inches of mulch as a top layer can help retain moisture and keep weeds away.
• Propagation: You can either propagate by seed or by softwood or semi-hardwood cuttings. Take your clippings in late spring or early summer.
• Soil and watering: These trees do best in slightly acidic soil, so it may be helpful to check a soil sample before you do your planting. Star magnolias will also grow in loamy, sandy, and clay soils. You should aim to keep the soil moist and well-drained, watering it weekly (more often in extreme heat).
• Sunlight: Plant your star magnolia where it can receive at least four hours of full sun each day.
• Winter care: Adding a couple of inches of compost in late winter can help encourage prolific blooms.

These trees also have a tendency to grow as multi-stemmed shrubs or bushes. Pruning can help eliminate lower growths to encourage your star magnolia to look more like a tree than a bush. Here are considerations for pruning your star magnolia:

• Time your pruning. You should prune around February, before the tree begins to bloom, or after the growing season ends, in late summer. Pruning during the dormant season will help you avoid pruning during the growing season, which would cause the bark to ooze sap.
• Trim the branches. Since the bottom branches may not receive as much sunlight and may not grow as well because of it, removing them early may be your best move. You’ll want to cut the bottom branches all the way to the trunk, which will also keep branches off the ground.
• Remove old blooms. Cut off old blooms without removing the growing points (just below the blossoms). Doing this will keep your stems healthy for next year’s blossoms.
• Thin the interior. If necessary, you can remove a few of the branches to thin the interior growth. This should be done lightly just to keep your tree shapely.
• Use caution. Growers generally do not prune much, although star magnolias tend to be more tolerant to pruning than other members of its genus. Since the flowers on the tree may not all blossom at the same time, be cautious when pruning to make sure you don’t snip away buds before they have had a chance to blossom.

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