How to Grow and Care for Saucer Magnolia

Saucer magnolia is a popular flowering tree or large shrub created by cross-breeding Magnolia liliiflora (lily magnolia, a shrub form) and M. denudata (lilytree), both native to Japan. It is sometimes called tulip magnolia, but it is not to be confused with tulip trees. It often grows as a multi-stemmed shrubby plant but can be trained into the form of a small tree by pruning it in its first years to have one central trunk.

The native saucer magnolia species has early spring pinkish-white flowers, but many cultivars are available with pure white, pure pink, magenta, and purple flowers. The plant has a nicely rounded crown, making it an ideal landscape specimen. It grows moderately, about 12 to 24 inches each growing season. Saucer magnolia heights can reach 25 feet tall, with a spread of 20 to 30 feet wide.

Saucer Magnolia Care

Saucer magnolia's rope-like tree roots grow horizontally to provide stability. Its roots do not grow invasively or deeply like other types of magnolia trees that can affect a home's foundation if planted too close.

Pruning can be done to shape the plant into a tree form, and you should prune diseased and broken branches 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.

The branches of saucer magnolia trees are favored by wildlife as nesting sites, and their seeds are a food source for birds. This tree is also moderately pollution tolerant.

Light

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

Soil

Though they will tolerate clay soils, saucer magnolia trees do best in moist, acidic, organically rich, and well-drained loam.

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 drought tolerance.

Temperature and Humidity

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

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; spread it over the surface around the plant, then water it in. For the amount to use, follow product label instructions.

Types of Saucer Magnolia

• Alexandrina (M. x soulangiana 'Alexandrina'): This multi-stemmed variety grows 20 to 30 feet high. This saucer magnolia hybrid is a cup-shaped plant with deep rose-purple flowers with white inside.
• 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 'Verbanica'): This cultivar grows 10 to 15 feet high with an upright, broad, pyramidal form. The flowers, which appear later than other varieties, are cup-shaped and rosy-pink with white inside. Lustrous dark green leaves turn coppery brown in fall.
• Lennei Alba (M. x soulangiana 'Lennei Alba'): This plant grows 12 to 24 feet high and wide with a broad, pyramidal form, making it ideal for small gardens. This saucer magnolia hybrid's flowers are pure white and globe-shaped; this tree flowers slightly later than the primary species.

Pruning

Saucer magnolia trees often produce multiple stems. To shape it into a tree form, prune away all but one central trunk. Or you can prune to just a few central trunks, 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.

If you are like most homeowners and acquired your saucer magnolia from the previous property owner rather than by planting your own sapling, early pruning won't be possible. Do not prune adult trees as you would a sapling. Only remove dead and damaged limbs. Call a certified arborist as needed.

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 with four to six cuttings, there's a good likelihood that one or two of them will succeed. It's best to take cuttings in summer after the buds have set. Take these steps.

1. Use a sterilized, 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 rooting hormone, 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 in humid conditions. Mist the cutting often and watch for roots to grow.
5. When a good network of roots has developed, transfer the plant to a larger pot filled with potting mix for continued growth. The magnolia can be planted in the landscape when vigorous upper growth has begun.

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 a 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 in a sunny or slightly shady spot to continue growth.

Replanting

Saucer magnolia seedlings (and transplants) are best planted in a full-sun to part-shade location—preferably not southern exposures, because the full sun can trick the flowers into opening too early when the cold early spring weather can damage the buds. 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.

Overwintering

Saucer magnolia is a hardy 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 severe insect or disease issues. However, it can be affected by leaf spots 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.

How to Get Saucer Magnolia to Bloom

The huge, early spring blooms of a saucer magnolia tree appear before its broad, dark green leaves. Saucer magnolia flowers may continue to bloom after the leaves emerge, usually blooming for one to two weeks. Magnolias started as cuttings often grow large enough to produce flowers within two to three years.

To get your saucer magnolias to bloom, the tree requires a very sunny but sheltered spot away from winds. Since they are early spring bloomers, a late frost may have damaged the buds, resulting in a poor bloom. Saucer magnolias are messy, but since it has a short bloom time, it's not a prolonged clean-up period. The spectacular, refreshing display makes the clean-up worth it.

Common Problems With Saucer Magnolia

Saucer magnolia is a hardy 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 drops are signs of common disease leaf spot. This condition doesn't require treatment.

Phytophthora root rot could be another possible cause of yellowing or wilting leaves and often affects a tree when the soil around the base has been wet for long periods. As the leaves begin to show symptoms, the inside of the tree trunk is becoming wet and damaged, which is why good soil drainage or planting trees in mounds is essential. Unfortunately, once symptoms occur the tree's poor prognosis is certain though the decline could be slow.

Black Growth on Leaves

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

Discolored Rings on Branches

Rings on the larger branches are often the result of sapsuckers, a type of woodpecker. Wrap the branches in burlap or hardware cloth to discourage revisiting.

White Powder on Leaves

This condition 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 1 tablespoon of horticultural oil to 1 gallon of water, sprayed thoroughly on the foliage.

Damaged Bark

The smooth bark of a saucer magnolia is thin and it can easily be nicked by a lawnmower or other garden tool. Damaged bark can let in disease and pests so it's very important to be careful when doing landscape maintenance. If the damage is done and is severe, you may need to protect the wounds with tree wrap. A professional arborist can better assess the damage.