Magnolia, Star Magnolia - Magnolia stellata

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Magnolia stellataMagnolia stellataMagnolias have a long history as magnificent additions to the garden, and especially the spring garden, when their naked branches are festooned with startling cup-shaped flowers. Discovered in the Orient, they were named in honour of the 17th century botanist Pierre Magnol and have graced western gardens for more than 300 years. Magnolia is an ancient genus; and having evolved before bees appeared, they are pollinated by beetles.  Fossilized Magnolia flowers along with the beetles were discovered in rocks dating around 100 million years old. Due to its great age this family of plants has survived major geologic events such as ice ages, continental drift, and mountain formation, causing its distribution to become disjunct or fragmented, isolating some species while keeping others in close proximity.

The family Magnoliaceae is widely distributed in temperate and tropical Asia from the Himalayas to Japan and southwest through Malaysia and New Guinea. East and south-east Asia is its main distribution centre with approximately two thirds of the species. The remainder of the family is spread across the Americas with temperate species extending into southern Canada, and a few tropical species extending into Brazil and the West Indies.

Magnolias are valued for their longevity, and in the wild they can be found growing in dense woodlands and forest, on moist, humus-rich soils. They occur mainly in tropical and subtropical climates but many varieties are quite hardy. They are represented by over 240 species and hundreds of varieties, both deciduous and evergreen; and are also highly diverse in their growth habit, from tall trees to various sized shrubs.

Magnolia stellata Picture courtesy Leonora Enking Visit her flickr photostreamMagnolia stellata Picture courtesy Leonora Enking Visit her flickr photostreamThe Star Magnolia (Magnolia stellata) is a slow-growing shrub or small tree native to Japan and can be found growing wild in certain parts of the Ise Bay area of central Honshu, Japan's largest island; at elevations between 50m and 600m. It grows alongside streams and in moist, boggy areas. This magnolia was introduced to the United States in the 1860s where it remains a popular landscape subject from coast to coast.

Like the saucer magnolia it is deciduous, revealing its twiggy, naked frame in winter. It is also a lot denser and more compact than the saucer magnolia. Young trees display a multi-stemmed, upright growth habit, spreading and mounding with age. Because it is very slow growing it is usually seen in home landscapes as a small to medium sized shrub; and will take about 10 years to reach only 1.2 to 1.5m tall. With maturity plants can reach +-4.6 to 6m tall with a spread of +-3 to 4.6m.

The star magnolia blooms when still very young; usually just after the saucer magnolia in late winter or early spring, and the bare branches are literally smothered in silky buds, opening to brilliant white or pink, slightly fragrant, star shaped flowers; blooming for several weeks. There is natural variation within the flower colour, from white to rich pink; and the hue of pink magnolias will change from year to year, depending on day and night air temperatures prior to and during flowering. A reddish-green, knobby fruit follows the flowers in early summer and opens by slits to reveal the orange-red seeds; but often the fruits will drop before developing fully. The main trunks have an attractive smooth, silver- grey bark and the young twigs are smooth and a shiny chestnut brown.

Magnolia stellata 'Jane Platt' Picture courtesy Lotus Johnston Visit her flickr photostreamMagnolia stellata 'Jane Platt' Picture courtesy Lotus Johnston Visit her flickr photostreamThis is one of the best magnolias for a small garden and the Royal Horticultural Society has given it its Award of Garden Merit (AGM). Try planting it against a dark background like a red brick wall or a stand of juniper for great contrast. Planted next to a pond it is breath-taking; with its lovely blossoms reflecting in the still water. Its graceful shape makes an excellent addition to woodland gardens and to other semi-shaded areas.  It is also an excellent specimen tree for the lawn or shrub border, and effective in foundation plantings near patios etc. or as an informal screening plant.

Magnolias are well suited to espalier which is the practice of controlling woody plant growth by tying the branches to a structure such as a wall or fence with a wood, steel or wire frame, so that the plants grow into a flat plane; frequently in formal patterns. Espalier, trained into flat two-dimensional forms, are ideal not only for decorative purposes, but also for gardens in which space is limited. In cold regions, if trained against a sunny wall or fence it will afford protection and warmth during the cold winter months. Despite this practice, reports of damage to the foundations of buildings or walls, is uncommon.  Initially the young shoots are bent down and tied very gently to only about 45 degrees, or they may break. During the growing season they can be encouraged into the more horizontal position required to train them along the frame. Prune regularly to remove any shoots growing towards the wall, and shorten outward-growing ones to one or two leaves. If these outward-growing shoots have flower buds, pruning can be delayed until immediately after flowering.

Magnolia stellata Picture courtesy Lotus Johnston Visit her flickr photostreamMagnolia stellata Picture courtesy Lotus Johnston Visit her flickr photostreamMagnolias are easy-to-grow and relatively pest free, and once established will need the minimum of attention. The star magnolia grows best in cool areas with good rainfall and mild winters. The plant itself is fully hardy, but the flowers are tender and often reduced to sad rags by late frosts and freezing winter winds. In cold regions position the plant in a sheltered part of the garden where it will not be exposed to very early morning sunshine in the winter, which will burn the frosted buds and flowers; a position with early shade and sun later in the day is best.  Thick mulch around the roots will help to prevent them from freezing.

The star magnolia is relatively pest free; and once established needs the minimum of attention. It requires adequate sun to flower well and will grow in full sun, or semi-shade. In sub-tropical and hot zones plant in a cool spot where it will be sheltered from the fierce midday sun and hot winds. In the winter rainfall regions plant in a wind protected spot and in very well-drained soil, water regularly in summer. It is not suited to the very dry parts of the country. It is most important to water regularly during dry spells, never allowing the soil to dry out totally.

Magnolia stellata 'Rose' Picture courtesy Peter RichardsonMagnolia stellata 'Rose' Picture courtesy Peter RichardsonBecause of its shallow root system the magnolia is sensitive to root disturbance and to its depth of planting, so do not plant it deeper than it is growing in its nursery bag, and keep mulch well away from the trunk. Once established magnolias are not easily transplanted, so ensure you plant it in the correct position.

Although the star magnolia thrives in a slightly acidic, loamy, well-drained soil which is rich in organic matter and retains moisture throughout the year; it is more tolerant of alkaline soils than other magnolias if the planting holes are well prepared with lots of acid compost and other organic material. Mulching the roots in summer will help to retain moisture and keep them cool. Specimens grown in heavy, compacted or poorly drained soil will appear stunted.

The plant needs adequate sun to flower well and will grow in full sun, or dappled shade; in cooler regions it will flower best in full sun but in the hotter regions of the country it will appreciate a bit of afternoon shade. It is most important to water regularly during dry spells, never allowing the soil to dry out totally. Feed in spring and late summer with a balanced organic fertiliser.

Magnolia buds Picture courtesy Lotus Johnston Visit her flickr photostreamMagnolia buds Picture courtesy Lotus Johnston Visit her flickr photostreamThe star magnolia usually needs little if any pruning, but if you do need to prune, do it immediately after flowering to avoid cutting off buds set for the next season. Remove any dead or weak growth and tidy as required. To train into a small tree cut away the lower branches so it can form a single trunk - this could take many years, but would be well worth the effort - kind of like having a bonsai growing in the ground.

Overall this is a trouble-free plant but it is susceptible to magnolia scale. 

Propagation is mainly by softwood cuttings taken in early summer or by semi-ripe cuttings taken in late summer; treated with a hormone rooting powder. Seed is slow to germinate and can take many months to germinate.

Additional Info

  • Common Name: Magnolia, Star Magnolia
  • Latin Name: Magnolia stellata