How to Grow and Care for Saucer Magnolia

Saucer magnolia is a popular flowering tree or large shrub that was created by cross-breeding Magnolia liliflora (lily magnolia, a shrub form) and M. denudata (lilytree). It often grows as a multi-stemmed shrubby plant but can be trained into the form of a small tree. The huge early spring blooms appear before the leaves, but smaller numbers of flowers sometimes continue to bloom after the leaves emerge. The native species has pinkish-white flowers, but many cultivars are available with pure pink, magenta, and purple flowers. The plant has a nicely rounded crown that makes it an ideal landscape specimen. It grows about 24 inches each growing season.

Saucer Magnolia Care

Saucer magnolias are best planted in a full-sun to part-shade location—preferably not on southern exposures since this can cause the flowers to open too early when cold early spring weather can damage the flowers. This tree doesn't like extremely dry or wet soil, so try to give it rich soil that is both moist and well-draining. It also does best if somewhat protected from strong winds.

Pruning can be done to shape the plant into a tree form, and diseased and broken branches should be pruned away to prevent the spread of fungal diseases. These plants often do fine without any feeding, but a spring application of fertilizer can help the plant thrive.

Light

Saucer magnolia trees prefer full sun, but they can tolerate partial shade locations.

Soil

Saucer magnolia trees do best in moist, acidic, organically rich, and well-drained, loamy soil, though they will tolerate clay soils.

Water

During the first year of planting, water the tree deeply and frequently. Afterward, saucer magnolias need irrigation only when the weather is dry. Once established, these trees have a moderately good tolerance for drought.

Temperature and Humidity

Cool, rainy weather tends to cause fungal leaf spots and cankers on magnolia plants. If possible, avoid splashing soil from the ground onto the plants, and give them good air circulation. They can handle a wide range of humidity.

Fertilizer

Magnolias are not heavy feeders, but they benefit from mixing fertilizer into the soil when planting, then lightly feeding them each spring with a balanced slow-release fertilizer. For annual spring feeding, do not mix the fertilizer into the soil, but rather spread it over the surface around the plant, then water it in.

Types of Saucer Magnolia

• Alexandrina (M. x soulangiana 'Alexandrina'): This multi-stemmed variety grows 15 to 20 feet high. It is a cup-shaped plant with deep rose-purple flowers with white interiors.
• Rustica Rubra (M. x soulangiana 'Rustica Rubra'): This plant grows 15 to 25 feet high with a broad, open, pyramidal form. The flowers are rose-red.
• Verbanica (M. x soulangiana 'Verbannica'): This cultivar grows 20 to 25 feet high with an upright, broad, pyramidal form. The flowers, which appear later than other varieties, are cup-shaped and rosy-pink flowers with white interiors. Lustrous dark green leaves turn coppery brown in fall.
• Lennei Alba (M. x soulangiana 'Lennei Alba'): This plant grows 15 to 20 feet high and wide with a broad, pyramidal form, making it ideal for small gardens. The flowers are globe-shaped and pure white; this tree flowers slightly later than the species.

Pruning

Saucer magnolia trees often produce multiple stems. To shape it into a tree form, prune away all but a one central trunk. Or you can prune to just a few central trunks, with the understanding that the tree will likely need additional support such as cabling or propping. Such drastic pruning should be done while the tree is still young. You may also shape the crown in later years by pruning lightly after the flowering period. Remove any dead or diseased branches as you see them, preferably in dry weather when fungi are less likely to infect pruning wounds.

Do not be alarmed by a dramatically leaning saucer magnolia; instead, consider having it propped. It is very common for these trees to grow with rather extreme leans.

Propagating Saucer Magnolia

Saucer magnolia is a fairly fast-growing tree that can be propagated from cuttings but be prepared for a good number of the cuttings to fail. If you start 4 to 6 cuttings, you have a good likelihood of 1 or 2 succeeding. It's best to take cuttings in summer after the buds have set.

1. Use a sharp knife or pruning shears to cut a 6- to 9-inch cutting from the tip of a branch. Immediately place the cutting into water to keep it moist.
2. Remove all but the upper leaves, then make a 2-inch vertical slice at the end of the stem.
3. Dip the stem into a hormone solution, then place the tip of the cutting into a planter filled with moist perlite.
4. Place the cutting in indirect light and cover it loosely with a plastic bag to keep the cutting humid. Mist the cutting often and watch for roots to grow.
5. When a good network of roots has developed, the plant can be transferred to a larger pot filled with potting mix for continued growth. When vigorous upper growth has begun, the magnolia can be planted in the landscape.

Magnolias started this way often grow large enough to produce flowers within two years.

How to Grow Saucer Magnolia From Seed

Gather the seeds of the saucer magnolia during spring and summer. They need a period of dormancy, so plan to plant the seeds outdoors in the fall, about 1/4 to 1/2 inch deep. The seeds should germinate in the spring.

It's possible to germinate the seeds indoors. Use an empty coffee can or similar container. Bury the seed in a few inches of moist peat moss, add the lid, and punch holes in the lid for air circulation. Place the can in the refrigerator for three to five months. When the time is up, remove the seed and plant it in a small container indoors. Keep the soil moist while the seed germinates. When spring rolls around and the threat of frost has passed, plant the germinated seed outdoors to continue growth.

Overwintering

Saucer magnolia is a hearty plant that needs no particular care to overwinter well. Keep watering it through the winter if snows and rains aren't quite enough and add a thick layer of mulch around the trunk to protect the root system from deep cold.

Common Pests and Plant Diseases

Saucer magnolia doesn't suffer from many serious insect or disease issues. However, it can be affected by leaf spot and canker, both caused by fungi. Copper-based fungicides regularly applied (preferably before the spots appear) can prevent fungal leaf spots. Prune away and destroy canker-damaged branches during dry weather, sterilizing the pruning shears after each cut.

Common Problems With Saucer Magnolia

Saucer magnolia is a hearty plant that presents few problems. However, fungal diseases might be an issue.

Spots, Yellowing, or Dropping Leaves

Small brown or black spots, yellowing leaves, or early leaf drop are signs of the common disease leaf spot. This doesn't require treatment.

Black Growth on Leaves

A black, velvety growth on leaves can indicate sooty mold. Treat this with a firm spray of water across the leaves, or a 2 percent solution of horticultural oil for serious cases.

Discolored Rings on Branches

This is often the result of target canker. Control the spread by cutting away affected branches.

White Powder on Leaves

This is known as powdery mildew, which can make the tree drop yellowed leaves early in the season. To treat, try a solution of 1 tablespoon baking soda to 2 1/2 tablespoons of horticultural oil to 1 gallon of water, sprayed thoroughly on the foliage.