Magnolia

Magnolia

Magnolias in the garden

Magnolias are a genus of trees and shrubs with a very showy flowering; there are about eighty species of magnolia in the world, and many are hybrids and cultivars. We can distinguish a group made up of tall evergreen trees, with leathery leaves and summer flowering, whose specimens are native to the North American continent; another group, on the other hand, is that of the Asian magnolias, also large shrubs, with deciduous leaves and late winter or spring flowering.

Magnolias are among the most popular flowering trees: they are in fact an unforgettable sight, with their delicate petals that sprout directly from the branches, even before the leaves, to indicate the arrival of summer.

Everyone can have the satisfaction of cultivating one, as there are many different sizes and behaviors. They can therefore be inserted in large parks, in small gardens or even grown in large containers, on balconies or terraces.

Magnolias come from East Asia and the east coast of the United States. They were known in Europe since ancient times, but their cultivation (in particular of persistent leaf varieties) spread from the eighteenth century.


The evergreen magnolias

Surely among the most cultivated tall-stemmed magnolias, first of all the magnolia grandiflora, a large tree, which reaches 15-20 meters in height, with bright green leathery leaves and large white flowers in summer, followed by particular infructescences woody, from which the small red fruits protrude. One of the first specimens grown in Europe can be admired in the botanical garden of Padua, where it seems to have been planted in the late eighteenth century. These trees have been grown for centuries in European gardens, especially in the large parks of stately villas and city gardens.

There are other species of this plant of American origin, even if they are generally difficult to find in Italy; for example M. acuminata and M. tripetala. These species are widespread in particular in the southern areas of the United States, and generally tolerate the Italian climate without problems.

Among the evergreen-leaved species there is also an Asian one, the Magnolia delavayi, with bright green foliage, and large, fragrant, fleshy white flowers that bloom in midsummer.

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Deciduous magnolias

The magnolias that lose their leaves are all of Asian origin and have been cultivated in Europe for centuries; most produce their large flowers in late winter or early spring before producing leaves; the beauty of these plants lies in being able to admire the bare trees adorned with splendid flowers.

The most common in cultivation are hybrids of magnolia x soulangeana, originating from the hybridization between m. liliflora and denudata magnolia; In this way small slow-growing shrubs have been obtained, which over the years can become small trees, with deciduous leaves, which in spring produce huge cupped flowers, white inside, pinkish outside.

Other widely cultivated magnolias are the starry magnolias, with large star-shaped flowers, of a pure white color, also blooming on the completely bare tree.

There are many other species, such as Magnolia kobus, magnolia obovata, magnolia officinalis, which are generally grown only in botanical gardens, or by collectors, and are not easily found in nurseries, despite being delicate and graceful plants.

These plants are also rustic and can be grown in the garden without any problems.

MAGNOLIA IN BRIEF
Name, genus, speciesMagnoliaceae, gen magnolia, more than 125 species
Type of plantDeciduous or persistent flowering tree or shrub
OriginsEast Asia, United States
Flower colorWhite, pink, crimson, yellow
MaintenanceSimple
GrowthSlow
RusticityMedium to very rustic
ExposureSun-half shade
GroundDeep, soft, rich, fresh, generally not calcareous
pH Usually acidic, but for some species also neutral or sub-alkaline
Water needAverage
HeightFrom 2 to 30 m
PropagationSowing, cutting, layering, grafting


Growing magnolias

Whether they are evergreen or deciduous, magnolias generally have similar needs; they prefer sunny positions, since in the shade they tend to produce little flowering. They are planted in fresh and deep soil, very well drained, as they do not like water stagnations; possibly it is good that the soil has a tendency to be acidic, in fact with the passage of time the cultivation in excessively calcareous soils can lead to a slight chlorosis, especially as regards the deciduous species.

Every year in autumn the soil at the foot of the plant is enriched with mature organic fertilizer, or with granular fertilizer; in order to guarantee the presence of mineral salts in the soil for a long period of time.

Generally the magnolias are satisfied with the water supplied by the bad weather, even if it is advisable to water the younger shrubs during the summer, and also the adult specimens in case of prolonged drought; watering may be necessary only during hot periods and should be provided when the soil is dry.

Generally, magnolias do not need pruning, as development is quite slow and the plants tend to produce a harmoniously shaped crown, without the need for human help. After flowering, we can remove damaged or poorly developed branches without over-pruning the plant.

As for very early flowering plants, it is advisable to place them in a place where they are not excessively exposed to wind or frost, to prevent the buds from being ruined by sporadic late frosts.


The name of the Magnolias

It was a French botanist who gave the name to the magnolias, in the late 1700s; this Plumier chose for these majestic plants the name of another botanist Pierre Magnol, the one who had introduced the concept of the botanical family into systematics.

In American gardens it seems that the magnolia was considered a sign of good luck; today the magnolia blossoms in bouquets symbolize dignity, perseverance and superb beauty.


Magnolia liliflora

Among the numerous hybrids of magnolia there is also a hybrid called Magnolia liliflora, very similar in characteristics to the magnolia soulangeana. The flower is in fact very similar and can be easily confused with a little careful analysis, but it is not the only similar aspect. The leaves of this plant are in fact deciduous and oval in shape, with a leathery consistency and a light green color.

There magnolia liliflora it blooms at the end of winter on the branches still without leaves and has an explosive flowering, with deep pink petals arranged in a cup.

There are several varieties of magnolia liliflora, such as liliflora nigra and liliflora susan, a variety created through a cross between magnolia rosea and magnolia nigra. Susan blooms in April and May and is one of the longest flowering magnolias.


Exposure and climate magnolias

Magnolias are generally quite rustic, but otherwise they are quite demanding when it comes to the climate. In fact, they require a context that is not too hot during the summer, but also not too humid during the bad season. Furthermore, cold winds and late frosts can permanently ruin the flower buds.

Ultimately, we can say that in the north of the peninsula the ideal is a position in full sun or with a little shade in the afternoon. However, let's make sure that the area is well lit and heated even during the coldest months. In addition to this, it may be useful to have a wall nearby, capable of blocking the winds and accumulating heat during the day. In the southern regions and on the coasts, however, it is important to ensure a substrate that is always slightly humid. Therefore, we choose an area that is well reached by the sun in the morning, but more sheltered during the afternoon hours.

THE CALENDAR OF MAGNOLIA
PlantSeptember-October / April
FloweringFrom March to September, depending on the variety
Training pruningAfter flowering
FertilizationOrganic: autumn; summary: spring
Cutting / graftingFrom mid-summer


Magnolia soil

The preferable soil must be rich, deep and soft, but at the same time well drained. Most species prefer acid-reacting soils, with a pH of 5.5 to 6.5.

If in our green space there was instead a clayey and alkaline substrate, it would be good to replace it totally or partially, perhaps mixing it with peat or specific soil for acidophilic plants and some very mature manure.

Alternatively, we choose more tolerant varieties, such as stellata and kobus.


How to maintain the acidity of the soil

Unfortunately, the proximity of a clayey soil and irrigation with calcareous water will inevitably return to raise the pH of that area over time. To avoid or minimize this problem it is good, if possible, to irrigate with rainwater. It can also be useful to sprinkle iron sulphate in autumn and spring, to be incorporated in depth. Mulching with peat, bark, and pine needles can also help. In case of emergency, when leaf chlorosis and scarce blooms appear, we can spread chelated iron in granules throughout the area covered by the canopy.


When to plant magnolia

Magnolias do not particularly like to be transplanted and it is therefore good to choose carefully the period in which to operate. For full success it is absolutely necessary to avoid doing it when frosts can occur.

The advice is to proceed to the North in early autumn (September-October) or late spring. In places with a mild climate, on the other hand, it is possible to do so even in the middle of winter, as long as the temperatures never drop below freezing.

Small plants (maximum 1.20 cm) recover more easily than the others and are therefore preferable during the purchase phase.


How to plant magnolia?

We dig a very large hole. At the bottom we prepare a draining layer based on gravel. Let's mix the extracted soil with a good quantity of peat and mature manure. We insert the plant, touching the delicate roots as little as possible, so that the grafting point is slightly raised above the ground level.

We compress well and irrigate abundantly and continuously for at least two months.


Crop care for magnolia

Magnolias, when grown in the right location, are plants with limited maintenance and very resistant to disease.

You will have to be a little more careful in the Center-South, during the spring and summer days, especially if hot and dry. The soil must always remain fresh: a thick mulch based on vegetable debris or, better still, pine bark can help us in this. With very high temperatures, the plant can benefit, in the evening, from leaf sprays that allow it to cool off and rehydrate.


Magnolia fertilization

To keep the soil vital and aerated, it is advisable to spread a good quantity of floured manure at the base in autumn to be incorporated into the soil in spring, with a light hoeing. Adding a little peat can be useful for maintaining the pH of the soil.

In March, it is good to distribute fertilizer for acidophilic plants or flowering plants, possibly with slow release, in the area covered by the foliage.


How to prune the magnolia

Pruning is not strictly necessary for magnolias. They grow with a naturally open and elegant shape.

However, if we want to educate them in a particular way, it is good to do it in the first 5 years of life, intervening after flowering, towards the end of April.

In emergency cases, to eliminate exhausted branches or branches damaged by cold or diseases, it is possible to intervene even in mid-autumn. The ideal is to operate by removing only those that are dead or that at birth appear particularly fragile.


Pests of magnolia

These are hardy plants. For flowering, the greatest danger is represented by slugs, which climb up the branches and feed on the young and tender buds. Let's keep them away with special products.

There is also the danger of root rot (which must be prevented with good drainage) and leaf drying (caused by excessive heat).


Propagate the magnolia

M. can be propagated by seed, cutting, layering or grafting. All of them, except the first, guarantee the maintenance of the peculiar characteristics of the cultivar, but to implement them you have to be quite experienced.

Cutting

It is certainly preferable to layering, which is really difficult to achieve. It is carried out on semi-finished wood, proceeding in mid-summer. We cut healthy and vigorous shoots with clean, sharp shears, below one eye, leaving a small tab of bark. We eliminate the apical bud and leave only a couple of leaves. We sprinkle with a rooting compound and insert in boxes with substrate obtained with soil, field earth, sand and perlite, in equal parts. We keep in a warm and humid, but shaded greenhouse.

Grafting

Grafting by approximation is the most used, especially on the most difficult cultivars to cut. This technique also gives the possibility to choose a more tolerant root system towards limestone and high pH.

The subjects, obtained from seed, most used are M. kobus (for deciduous trees) and M. Grandiflora (for evergreens).


Variety of magnolia

There are more than 125 species of Magnolia and the hybrids and cultivars are not counted. Here are the most common:

GuyVarietyFlowersHeightFlowering periodOther characteristicsOther
Deciduous leafMagnolia kobusSmall fragrant white flowers, pink fruitsUp to 10 mMarch AprilTolerates calcareous soil. Suitable for this as a rootstock. Withstands up to -15 ° C and withstands the shadeFrom Japan

Among the simplest and most tolerant

Magnolia x loebneriStar flowers, up to 14 petals, from white to soft pinkFrom 5 to 10 mAprilHybrid available in different cultivarsFull sun, tolerates late frosts well
Magnolia x soulangeanaCream flowers with pink streaks, tulip-shaped.Up to 6 mApril MayWithstands up to -20 ° C

Many cultivars available

Very widespread, spreading habit, flowers before the leaves
Magnolia liliifloraLong, white or purple petals. Approximately 7 cm in diameterUp to 4 mFrom April to July, the longest. Can repeat in the fallUp to -15 ° C Beautiful pointed and shiny leavesCultivar: nigra (compact), purpurea (pink flowers).
Starry magnoliaLarge starry flowers all along the branchVery compact, up to 3 mMarch AprilVery rustic and resistant, down to -25 ° CIt also grows in calcareous soil. Suitable for vases
Magnolia denudataCup-shaped, white, about 15 cm in diameter5 to 10 m, pyramidal shapeMarch AprilUp to -15 ° CFrom China, large, glossy leaves
Magnolia sieboldiCupped, semi-dependent, white with red center, very fragrant10 footMayVery rusticFrom Japan and Korea. Thin branches and oblong leaves. Acid soil.

Suitable for vase

Magnolia obovataLarge, cupped, creamy white and / or purple, very fragrant30 mMay JuneVery rusticFrom Japan

Leaves up to 45 cm and 20 cm wide, very beautiful

Magnolia stellata x liliflora "Susan"Large, tulip-shaped dark pink, very fragrant2-4 metersApril MayUp to -15 ° CInteresting foliage, also suitable for pots
Persistent leafyMagnolia grandifloraCupped flowers, large, in white, pink or purple. Very fragrantMore than 30 metersVery long, generally from June to September-OctoberUp to -25 ° COriginally from the United States

Available in many varieties and cultivars with different flower colors, but also variegated leaves.

Among the most widespread in the North.

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