Metrosideros umbellata

Southern rātā
Southern rātā near Franz Josef Glacier
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Myrtales
Family: Myrtaceae
Genus: Metrosideros
Species: M. umbellata
Binomial name
Metrosideros umbellata
Cav.
Distribution of M. umbellata in mainland New Zealand. Auckland Islands not shown.

Southern rātā (Metrosideros umbellata) is a tree endemic to New Zealand. It grows up to 15 metres (49 ft) or more tall with a trunk up to 1 metre (3 ft 3 in) or more in diameter. It produces masses of red flowers in summer. Unlike its relative, northern rātā, this species rarely grows as an epiphyte.

Description

The flowers of southern rātā are scarlet, with stamens about 2 centimetres (0.79 in) long. White or yellow flowers are also known. Flowering usually occurs between December and February, but this depends on local conditions. Leaves are from 3 centimetres (1.2 in) to 6 centimetres (2.4 in) long, and are sharply pointed. The wood is hard, dense, and very strong. The bark is rough and flaky and provides an ideal stratum for the roots of epiphytic plants such as Astelia species and Freycinetia banksii (Kiekie). Southern rātā is a major source of honey on the West Coast of the South Island. Kākā, tui, and bellbirds visit rātā to take advantage of the abundant nectar.

Southern rātā growing at its southern limits in the Auckland Islands at 50°S

Distribution

It prefers cooler regions with high rainfall and is particularly common along the west coast of the South Island where its nectar is the main source of a locally produced rātā honey. Southern rātā is the most widespread of the New Zealand tree rātā species. It is locally present in the North Island from latitude 36° southwards, is more common in western parts of the South Island but absent from much of the east, and is common on Stewart Island (47°S) and in the Auckland Islands, where it reaches its southern limit at just over 50°S.

Conservation

Although southern rātā is not regarded as threatened, it is rather uncommon in the North Island, and in certain areas it is threatened by possum browse. In the Tararua range, southern rātā populations appear to have been replaced by a population consisting of hybrids between northern and southern rātā.

Project Crimson is a charitable trust that promotes conservation of rātā as well as the related pōhutukawa.

Cultivation

Southern rātā is a beautiful specimen tree, but growth can be slow unless it is grown in ideal conditions with moist soil. It is easily grown from fresh seed. While it is possible to grow the tree from softwood or semi-hardwood cuttings, these often prove reluctant to strike roots. It is ideal for coastal environments because it has a good resistance to wind and salt.[1]

At least 16 cultivars of southern rātā have been released.[2] There are also known cultivars of hybrids between southern rātā and pōhutukawa, and between northern rātā and southern rātā.[3] Known cultivars include:

Cultivar name Year introduced Flower colour Introduced by Notes
M. umbellata ‘Alba’[2] mid-1980s White/cream Denis Hughes Leaves are a paler lemon-green then standard plants. Sourced from Soaker Hill in the Catlins, South Otago.
M. umbellata ‘Christmas Dream’[2] Late 1970s Red Denis Hughes Sourced from Lake Manapouri.
M. umbellata ‘Denniston Yellow’[2] 1995 Sulphur Yellow Deane Keir Sourced from the Denniston Plateau.
M. umbellata ‘Fireball’[2] 1993 Bright crimson Deane Keir Sourced from the Stockton Plateau at a place called Burning Mine.
M. umbellata ‘Firecracker’[2] 1995 Deep red Jeff Elliott Sourced from Whanganui Inlet, North-West Nelson.
M. umbellata ‘Gold Beacon’[2] - Sulphur Yellow Les Cleveland Sourced from the Otira Gorge.
M. umbellata ‘Gold Nugget’[2] 1992 Red Joe Cartman Golden new leaves with thin red leaf margins. Sourced from side-shoot of M. umbellata ‘Harlequin’. Also sold as M. umbellata ‘Lownug’.
M. umbellata ‘Harlequin’[2] md-1980s Red Joe Cartman Variegated cultivar with yellow leaf margins. Sourced from Nugget Point.
M. umbellata ‘Kaka’[2] late-1990s Pink Denis Hughes Sourced from Kaka Point, Otago.
M. umbellata ‘Moonlight’[2] 2001 Red Pattersons Nurseries Reverse variegated cultivar. Sourced from side-shoot of M. umbellata ‘Gold Nugget’. Also sold as M. umbellata ‘Lowmoo’.
M. umbellata ‘Mt Augustus’[2] Late-1970s Red Louise Salmond Sourced from the Stockton Plateau at a place called Mt Augustus.
M. umbellata ‘Red Tips’[2] Mid-1990s Red Les Cleveland New leaves have a red tip. Sourced from an island in Lake Wanaka.
M. umbellata ‘St Nicholas’[2] Late 1970s Red Denis Hughes Sourced from Lake Manapouri.
M. umbellata ‘Scarlet Beacon’[2] 2002 Red Les Cleveland -
M. umbellata ‘Silver Beacon’[2] Mid-1990s Red Les Cleveland New leaves have a silvery tip. Sourced from an island in Lake Wanaka.
M. umbellata ‘Sparrow’s Hybrid’[2] 1994 Red Mr Sparrow Sourced from the banks of the Avon River in Christchurch, between Madras and Manchester Streets. Source material provided by Mr Sparrow, a customer of the nursery. Despite the name, this cultivar is not a hybrid.
Metrosideros ‘Cleveland Red’¤[3] late-1990s Scarlet[4] Les Cleveland Deliberate interspecific hybrid.
Metrosideros ‘Maungapiko’¤[3] 1985 Bright crimson Graeme Platt Sourced from Maungapiko Track, Great Barrier Island.
Metrosideros ‘Rustic Beauty’¤[3] 1985 - Les Cleveland Deliberate interspecific hybrid.
Metrosideros ‘Sentinel Flame’∞[3] 2007 Bright red[5] Graeme Platt / Vibrant Earth nursery Sourced from either Great Barrier Island or North-West Nelson.

∞ Hybrid of southern rātā and northern rātā
¤ Hybrid of southern rātā and pōhutukawa

See also

References

  1. ↑ "Gondwanan Plants What Are They and Why Grow Them in Britain?". Garden Cottage Nursery. Retrieved 2009-06-18.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 "Metrosideros in cultivation: Rātā and other species" (PDF). 13 (2). 2010: 11.
  3. 1 2 3 4 5 "Metrosideros in cultivation: Pōhutukawa" (PDF). New Zealand Garden Journal. 13 (1): 10–22. 2010. Retrieved 2015-05-25.
  4. ↑ "Metrosideros Cleveland Red (umbellata x excelsa)". NZ Colour Labels. Retrieved 21 June 2015.
  5. ↑ "Metrosideros umb x rob 'Sentinel Flame'". Vibrant Earth. Vibrant Earth. Retrieved 16 June 2015.

Further reading

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