Large, fragrant, white blossoms are just the beginning of the appeal of a magnolia tree. These attractive trees also feature glossy, dark green leaves and a large, exotic-looking pod that opens in fall to reveal bright orange-red berries which are relished by birds and other wildlife. Learning more about magnolia planting and care is a great way to enjoy these trees in your landscape.
I. Appearance and Characteristics
Magnolias are spreading evergreen or deciduous trees or shrubs characterised by large fragrant flowers, which may be bowl-shaped or star-shaped, in shades of white, pink, purple, green, or yellow. In deciduous species, the blooms often appear before the leaves in spring. Cone-like fruits are often produced in the autumn.
As with all Magnoliaceae, the perianth is undifferentiated, with 9–15 tepals in three or more whorls. The flowers are hermaphroditic, with numerous adnate carpels and stamens arranged in a spiral fashion on the elongated receptacle. The flowers’ carpels are extremely tough to avoid damage from pollinating beetles.
The fruit dehisces along the dorsal sutures of the carpels. The pollen is monocolpate, and the embryonic development is of the Polygonum type.
Taxonomists, including James E. Dandy in 1927, have used differences in the fruits of Magnoliaceae as the basis for classification systems.
II. How to Grow and Care
Sunlight
Magnolia varieties prefer full sun to light shade. In warmer or dry climates, they appreciate some shade in the afternoon.
Temperature and Humidity
Magnolia trees prefer warm and humid climates. Seedlings can be susceptible to frost damage. Some varieties, such as the Star magnolia (Magnolia stellata) do not tolerate heavy snow and ice well. Sweet bay magnolia (Magnolia virginiana) doesn’t have special temperature needs. Just plant it within the hardiness zone (USDA 4-10).
Watering
Once established, magnolias can be fairly drought-tolerant. For the first three to six months, young magnolia trees need to be watered two or three times per week. After that, the tree will need to be watered weekly until it is established (usually for the first two years of its life.) Give the tree two to three gallons of water for every inch of trunk diameter every time you water.
Gauge the tree’s water needs based on the temperature and rainfall in your area. For instance, if it rains a lot three times in a week, you won’t need to water the tree that week. Additionally, if it’s really hot outside, you may need to water more frequently. Mulching around the base of the tree, but not near the trunk, will help keep water in. Leaves on the tree will begin to droop if you are overwatering.
Soil
These trees grow best in moist, well-drained soil that is slightly acidic, but a range of pH levels offer suitable growing conditions for them. While they can adapt to sandy, loamy, and clay soils, magnolias do not grow well in soils with poor drainage.
Fertilizing
Magnolia trees should be fertilized once a year in early spring with a slow-release, organic fertilizer. A balanced fertilizer with a ratio of 14-14-14 or 10-10-10 performs well for the magnolia tree. Because of the magnolias’ wide root system, you will need to spread the fertilizer wide, up to 10 inches away from the trunk base. Early spring is when the magnolia tree is in its season of active growth, making it the perfect time to fertilize. Using fertilizer unnecessarily on some magnolias, like Sweet Bay, can cause fertilizer burn.
Planting Instructions
For any magnolia, be sure to pick your planting site carefully. Virtually all types are hard to move once established, and many grow quite large, which makes them nearly impossible to move later. The best soil for magnolias is fairly rich, well-drained, and neutral to slightly acid; if necessary, add generous amounts of organic matter when planting.
Southern magnolia (M. grandiflora) is good for planting at the beach, though not on dunes. It can stand up to some salty sea breezes. Sweet bay (M. virginiana) tolerates wet soil. The species and selections listed are adapted to a wide range of growing conditions and are easy for most gardeners to grow.
Magnolias never look their best when crowded, and they may be severely damaged by digging around their roots. Larger deciduous sorts are most attractive standing alone against a background that will display their flowers at bloom time and show off their strongly patterned, usually gray limbs and big, fuzzy flower buds in winter. Small deciduous magnolias show up well in large flower or shrub borders and make choice ornaments too. Most magnolias are excellent lawn trees; try to provide a good-size grass-free area around the trunk, and don’t plant under the tree.
Balled-and-burlapped plants are available in late winter and early spring; container plants are sold all year. Do not set plants lower than their original soil level. Stake single-trunked or very heavy plants to prevent them from being rocked by the wind, which will tear the thick, fleshy, sensitive roots. To avoid damaging the roots, set stakes in the planting hole before placing the tree.
Propagation
The best time to propagate a magnolia is in the summer after its buds have set with cuttings from young growth. Follow these steps to properly propagate your magnolia tree:
- Use sharp pruners or a knife to cut a 6-inch piece from the tip of the branch. Immediately place the cutting in water. Remove the lower leaves, keeping a few upper leaves intact. Cut above a node.
- Dip the stem into a hormone rooting solution and plant the cutting into a 10- to 12-inch pot filled with moist, well-drained rooting medium.
- Place the pot in a bright location, cover it with plastic, and keep moist until the cutting develops a system of roots.
How to Grow From Seed
To grow a magnolia tree from seed, follow these steps:
- Collect seeds from fallen cones during the fall. Let the cones dry and open them to collect the seeds.
- Soak the seeds in warm water for one to two days to soften the seed coating.
- Remove the seeds from the water and dry them to remove the coating.
- Pack the seeds with moist peat moss in a plastic bag and refrigerate them during the winter.
- When outdoor temperatures reach 70 degrees, plant the seeds in the desired location in your yard. Mulch the seedlings well and protect them during the first few winters.
How to Get to Bloom
Magnolia trees bloom in ivory whites, pale yellows, and pretty pinks, with some species flowering in the heat of summer and others blooming in late winter as harbingers of warmer weather to come.
It can take several years for a young magnolia tree to bloom, especially if it was an unnamed, generic variety when purchased. Look for magnolia selections that are named, as they bloom earlier, or buy a tree with blooms or buds already on it.
Magnolia trees need lots of sunlight to bloom, so make sure to plant them in a sunny spot. Pruning your tree incorrectly, over-fertilization, and root damage can also prevent magnolia trees from blooming.
Pests and Diseases
Common Pests and Plant Diseases
Magnolias have relatively few issues with pests and diseases, but there are some fungal diseases and pests you may encounter with a magnolia that can be treated.
If you notice a branch dies suddenly while the rest are healthy, the fungal disease canker may be to blame. Prune the dead branch along with a few inches of new growth, and dispose of the affected branch properly.
Leaf spot is another common disease that affects magnolia trees, however, it is usually not dangerous to the plant and only requires you to cut off the affected area. Symptoms of leaf spot include black or brown spots on the foliage, yellowing, or early leaf falling.
Issues with black twig borer have recently become more common, especially on Southern magnolias. These insects attach younger stems, about the size of a pencil. You’ll notice dieback on the tree from the tip. Address the problem by cutting into good green tissue about 3-4 inches deep. These pests often won’t kill the tree but can cause unsightly damage.
Common Problems
Once established, magnolia trees are pretty low-maintenance trees that rarely have problems with pests and disease. However, there are a few issues you should watch out for. Thankfully, most problems with magnolia trees can be easily treated by pruning or spraying with a horticultural oil.
Leaves Turning Yellow/Plant Leaves Falling Off
If a white powder is present on the leaves, the magnolia tree may drop yellowed leaves early in the season. Apply a horticultural oil or neem oil to help control the powdery mildew.
Yellowing, early dropping, or small black or brown spots on magnolia leaves indicate leaf spot, which is a common disease that doesn’t cause significant damage or require treatment. Remove any affected fallen leaves to keep the problem under control.
Sooty Mold
Velvety black growth on the leaves means sooty mold is present. Spray water across the surface of the leaves to wash it away, or treat more severe cases with horticultural oil.
III. Uses and Benefits
- Horticultural uses
In general, the genus Magnolia has attracted horticultural interest. Some, such as the shrub M. stellata (star magnolia) and the tree M. × soulangeana (saucer magnolia) flower quite early in the spring, before the leaves open. Others flower in late spring or early summer, including M. virginiana (sweetbay magnolia) and M. grandiflora (southern magnolia). The shape of these flowers lend themselves to the common name tulip tree that is sometimes applied to some Magnolia species.
Hybridisation has been immensely successful in combining the best aspects of different species to give plants which flower at an earlier age than the parent species, as well as having more impressive flowers. One of the most popular garden magnolias, M. × soulangeana, is a hybrid of M. liliiflora and M. denudata.
In the eastern United States, five native species are frequently in cultivation: M. acuminata (as a shade tree), M. grandiflora, M. virginiana, M. tripetala, and M. macrophylla. The last two species must be planted where high winds are not a frequent problem because of the large size of their leaves.
- Medicinal uses
The bark and flower buds of M. officinalis have long been used in traditional Chinese medicine, where they are known as hou po (厚朴). In Japan, kōboku, M. obovata, has been used in a similar manner.
- Culinary uses
The flowers of many species are considered edible. In parts of England, the petals of M. grandiflora are pickled and used as a spicy condiment. In some Asian cuisines, the buds are pickled and used to flavor rice and scent tea. In Japan, the young leaves and flower buds of Magnolia hypoleuca are broiled and eaten as a vegetable. Older leaves are made into a powder and used as seasoning; dried, whole leaves are placed on a charcoal brazier and filled with miso, leeks, daikon, and shiitake, and broiled. There is a type of miso which is seasoned with magnolia, hoba miso.
- Timber
The cucumbertree, M. acuminata, grows to large size and is harvested as a timber tree in northeastern US forests. Its wood is sold as “yellow poplar” along with that of the tuliptree, Liriodendron tulipifera. The Fraser magnolia, M. fraseri, also attains enough size sometimes to be harvested, as well.
- Other uses
Magnolias are used as food plants by the larvae of some Lepidoptera species, including the giant leopard moth.
