Australian in cultivation: and The first of a two-part series

Murray Dawson1

When Johann Reinhold Forster (1729– many Australian species and cultivars (1992), Griffiths (1994), Lord (1999, 1798) and his son Johann Georg make excellent garden subjects. and previous years), Philip (2008, and Adam Forster (1754–1794) described Some are well-recognised and widely previous years), Philip et al. (2012, and Leptospermum (family ), cultivated around the world, but others previous years), and in the RHS they aptly named the genus after its are scarcely known and deserve wider Finder online (http://apps.rhs.org.uk/ characteristic seeds (from the Greek planting. rhsplantfinder/index.asp). ‘leptos’ meaning thin or slender and Although most species are too tender These key references are generally ‘sperma’ meaning seed). In 1776, the for cultivation in countries with harsh up-to-date. However, background Forsters described the type species, winters, several are naturally adapted information on origins can L. scoparium J.R.Forst. & G.Forst. In to cooler, montane regions in the wild be lacking and the correct species the British Isles, this species was first (e.g., species from south-eastern and cultivar names for several offered for sale in nursery catalogues and ), making them leptospermums have become of around the same era (from the relatively hardy in cultivation. Some of confused. Misidentified and 1700s), but under botanical names in these hardier leptospermums include: redundant or misspelt names are Philadelphus. L. arachnoides Gaertn., L. argenteum frequently perpetuated, despite the Early European settlers to Joy Thomps., L. brachyandrum availability of current names. These chose the common (F.Muell.) Druce, L. continentale Joy problems are shared with many plant name ‘tea-’ for this species, Thomps., L. coriaceum (F.Muell. groups that have a long horticultural following usage of the as a ex Miq.) Cheel, L. epacridoideum history. tea substitute dating back to Cook’s Cheel, L. glaucescens Schauer, This article discusses the voyages (Brooker et al., 1988). This L. grandiflorum Lodd., L. grandifolium nomenclature, and common name is now used widely Sm., L. juniperinum Sm., L. lanigerum horticultural qualities of noteworthy for all species of Leptospermum (and (Aiton) Sm., L. macrocarpum Australian leptospermums. Emphasis for alternifolia Maiden & (Maiden & Betche) Joy Thomps., is placed on species2 suitable for Betche ex Cheel). L. micromyrtus Miq., L. minutifolium cultivation in cooler climates. Part One (Benth.) C.T.White, L. myrsinoides Currently there are 87 wild species documents species and the origins Schltdl., L. myrtifolium Sieber ex of Leptospermum recognised of cultivars selected from them, and DC., L. nitidum Hook.f., L. obovatum (Dawson, 2009). Australia is the attempts to resolve, or at least highlight, Sweet, L. rotundifolium (Maiden & centre of diversity for the genus some of the issues surrounding their Betche) F.A.Rodway, L. rupestre where most species are endemic; names. Part Two will discuss the Hook.f., L. sphaerocarpum Cheel, only L. scoparium extends from interspecific hybrids (crosses between L. squarrosum Gaertn., L. trinervium mainland Australia and Tasmania Leptospermum species) that have (Sm.) Joy Thomps., L. turbinatum Joy to New Zealand and L. parviflorum arisen in the wild and from cultivation. Thomps., and L. variabile Joy Thomps. Valeton extends from northern Acknowledgements and references will Australia to New Guinea. Elsewhere, A major taxonomic revision of the be included at the end of the second L. javanicum Blume naturally occurs genus was published by Australian part. in South East Asia and L. recurvum botanist Dr Joy Thompson in 1989. This article follows my previous reviews Hook.f. is endemic to Mt Kinabalu in Leptospermums that are worthy on selections of the New Zealand Borneo. of cultivation are discussed in the species, L. scoparium J.R.Forst. & Australian gardening books of Wrigley Among species, plant height, growth G.Forst., discovered from the wild and Fagg (1996, 2012), Greig (1987, habit, and characteristics and those raised in cultivation. These 1996), Elliot and Jones (1993) and vary greatly. Most leptospermums reviews were originally published listed by Hibbert (2004). Those flower during spring and summer, in The New Plantsman (Dawson, grown in New Zealand are listed by when they become smothered in 1997a, 1997b) and updated in The Gaddum (1997, 1999a, 1999b, 2001); white, greenish-white, cream, pink, red New Zealand Garden Journal (Dawson, those grown in the UK are listed or purplish coloured blooms according 2009, 2010). in the Plant Finder by Huxley et al. to species. Because of this variation,

1 Landcare Research, PO Box 40, Lincoln 7640, New Zealand; [email protected] 2 I have mainly followed the leaf and flower measurements of Thompson (1989). However, these dimensions can be larger in cultivated plant material, and Thompson’s measurements were taken from dried herbarium material collected from wild specimens.

14 New Zealand Garden Journal, 2012, Vol. 15(2) Australian Leptospermum Ollerenshaw (pers. comm.) of Bywong L. scoparium. Ollerenshaw named one scoparium Nursery (Bungendore, New South selection of this cross L. scoparium In contrast to a colourful Australian Wales). He has used it as a parent for ‘Freya’ (Plant Varieties Journal, 1998, flora, many New Zealand native plants some of the crosses in his breeding Vol. 11, No. 4). L. scoparium ‘Freya’ have rather dull that are often programme (Ollerenshaw, 1996; see (Fig. 3) is a relatively low-growing white or green. It is not surprising Part Two). L. ‘Asbestos Range’ is not (1–1.5 m tall) with green leaves then that plant collectors have actively commercially available. that produces abundant, soft-pink propagated flower variants from flowers. Another selection collected from New Zealand populations of typically Tasmania, but sold in the UK, is white-flowered L. scoparium J.R.Forst. L. scoparium ‘Zeehan’. Seed was & G.Forst., where it is commonly collected in the vicinity of Zeehan called maˉnuka. As documented in 1990, and grown on by Graham previously (Dawson, 1997a, 1997b, Hutchins of County Park Nursery 2009, 2010), these New Zealand (Hornchurch, Essex). This selection variants have provided genes for has white flowers, an upright growth cultivars with white, pink and red habit, and is claimed to be stronger flowers that are single or double. growing and with shaggier bark than is also New Zealand L. scoparium (Graham native to Australia3, and occurs Hutchins, pers. comm.). Fig. 2 Pots of the dwarf, bronze-leaved Leptospermum scoparium ‘Nanum Rubrum’ naturally in , Although collected and named by for sale at the E. F. Jenkin & Sons Nursery, and Tasmania (Thompson, 1989). Cranbourne South, Victoria, Australia. This is him, Graham Hutchins no longer Flowers of Australian L. scoparium a selection from New Zealand L. scoparium. grows an older Tasmanian selection, are almost always white (8–12 mm Photo: Murray Dawson. L. scoparium ‘Tasman’. Hutchins in diameter) with pale-pink flowered raised this selection from seed he forms being very rare (Elliot and collected from Tarraleah in 1985 Jones, 1993). Few cultivars of this (County Park Nursery information species have been selected from sheet 17–19, 1989). Like many Australia, and those that have of Hutchins’ wild-collected plants, were chosen mainly on the basis L. ‘Tasman’ and L. ‘Zeehan’ are not of vegetative rather than floral significantly different from the usual characters. range of variation found in the wild. Although Thompson (1989) did not recognise any varieties or subspecies of L. scoparium, var. Fig. 3 Leptospermum scoparium ‘Freya’, a eximium B.L.Burtt. is very distinctive. hybrid raised at Bywong Nursery, Australia. Photo: Peter Ollerenshaw. Warwick Harris (pers. comm.) has seen populations of this variety in the Although Elliot and Jones (1993) wild and also adjacent populations claimed Leptospermum ‘Horizontalis’ of “typical” L. scoparium with which it to be a selection of L. scoparium introgresses. This coastal, south-east collected from western Victoria, Fig. 1 Leptospermum scoparium ‘Asbestos Tasmanian variety was first introduced Wrigley and Fagg (1996) state that it Range’ growing at Bywong Nursery, into England in the 1930s, from seed is probably a cultivar of L. continentale New South Wales, Australia. collected near Port Arthur (Elliot and Joy Thomps. It has also been sold Photo: Peter Ollerenshaw. Jones, 1993). as L. ‘Portlandii’ and L. juniperinum An exception is provided by a ‘Horizontalis’. L. ‘Horizontalis’ is a Peter Ollerenshaw has successfully pink-flowered form collected from cold-hardy and pendulous selection. crossed L. scoparium var. eximium northern Tasmania. L. scoparium Material that I have examined has a with L. scoparium ‘Nanum Rubrum’. ‘Asbestos Range’ (Fig. 1) is named dense growth habit and very prickly As currently circumscribed this is after Asbestos Range (Narawntapu leaves making them good amenity a cross within the same species. National Park) from which the plant landscape plants. However, the parents differ markedly was obtained. This selection has dark in form and provenance; variety Leptospermum grandiflorum receptacles, surrounded by a ring of eximium is from Tasmania and and L. grandifolium reddish filaments, and a pink blush at has a pendulous habit, whereas Both L. grandiflorum Lodd. and the base of the . L. ‘Asbestos L. ‘Nanum Rubrum’4 (Fig. 2) is a dwarf L. grandifolium Sm. have a long Range’ was collected in 1990 by Peter cultivar derived from New Zealand history of cultivation, and have at times

3 According to the New Zealand Plant Conservation Network (www.nzpcn.org.nz) webpage on Leptospermum scoparium var. scoparium, most Australian forms of L. scoparium do not match the range seen in New Zealand. However, plants from Tasmania are very similar to, if not identical with some South Island forms. Further study using DNA sequencing is underway to resolve the status of L. scoparium forms both in New Zealand and in Australia. 4 Leptospermum scoparium ‘Nanum Rubrum’ is a name used in Australia for a dwarf cultivar with green-red foliage and red single flowers. I suspect that this selection may have been renamed in Australia, and could correspond with an older cultivar such as the English-raised L. ‘Boscawenii Minor’ or L. ‘Nichollsii Nanum’, or perhaps one of Duncan & Davies’ dwarf selections such as L. ‘Huia’ or L. ‘Ruru’ raised in New Zealand; critical comparisons are needed.

New Zealand Garden Journal, 2012, Vol. 15(2) 15 been confused due to the similarity of tea-tree because it is said to be late Harris, pers. comm.). L. coriaceum their names. L. grandiflorum (Fig. 4) flowering. This species is native is widespread in , is named after its moderately large to eastern Tasmania where it is New South Wales and Victoria, flowers (20–30 mm in diameter), relatively common. L. grandiflorum and has previously been known as whereas L. grandifolium (Fig. 5) is is cultivated in Australia and New L. laevigatum var. minus Benth. named after its distinctive long leaves Zealand, and was introduced into (up to 35 mm in length; Thompson, England sometime before 1821. This 1989). species is sometimes grown under its earlier names, L. nobile F.Muell. ex Miq. and L. rodwayanum Summerh. & H.F.Comber. Leptospermum grandifolium is also known as the mountain tea-tree because it is naturally found on the tablelands of New South Wales and the highlands of Victoria. This species has white flowers (12–20 mm in diameter) and leaves that are green and glossy on the upper surface and glabrous or densely hairy underneath. L. grandifolium is not as widely cultivated as L. grandiflorum, and Elliot and Jones (1993) state that it was possibly introduced into England in 1810 incorrectly under the name of the Fig. 6 Botanical illustration of Leptospermum other species (L. grandiflorum). laevigatum (then as Fabricia laevigata) in Curtis’s Botanical Magazine, London, Vol. 32, Leptospermum laevigatum Tab. 1304 (1810). Image courtesy Missouri (coast tea-tree) Botanical Garden, www.botanicus.org. Fig. 4 Botanical illustration of Leptospermum The common name for L. laevigatum Leptospermum laevigatum ‘Flamingo’ grandiflorum in Loddiges, C., The Botanical (Gaertn.) F.Muell. is coast (or coastal) is one of two leptospermums Cabinet, Vol. 6, Tab. 514 (1827). Image tea-tree, because it naturally occurs courtesy Missouri Botanical Garden, commercially available with www.botanicus.org. on coastal sand dunes and cliffs variegated foliage (the other is in New South Wales, Victoria, and L. juniperinum ‘Little Lemon’). Tasmania (Thompson, 1989). It is a L. laevigatum ‘Flamingo’ has slightly widespread and adaptable species smaller leaves than is typical for with greyish-green foliage and white the species, an attractive cream flowers of moderate size (15–20 mm and green variegation, and pink- in diameter). In Australia, the coloured new growth. The cultivar vigorous nature of L. laevigatum has originated in Australia at Facey’s allowed it to escape and spread from Nursery (Cranbourne, Victoria). Rex landscaping, coastal plantings, and Trimble raised it in 1971 as a chance following its use for revegetation after seedling amongst a batch of 2000 sand-mining. It has also naturalised other seedlings. In 1977, Facey’s in parts of New Zealand, South Africa, Nursery announced the release of this and the USA, particularly in warmer cultivar for sale in Your Garden (at areas such as California where it has the time, Australia’s widest circulating been planted to stabilise coastal sand gardening magazine). They released dunes. However, L. laevigatum is not it under the name L. ‘Flamingo’, but as troublesome when grown in cooler on the cultivar registration form they regions of the UK, where it has been proposed the name L. ‘Raelene’. cultivated since the late 1700s (then As the name L. ‘Flamingo’ was Fig. 5 Botanical illustration of Leptospermum under the name Fabricia laevigata validly published in Your Garden grandifolium in Loddiges, C., The Botanical Gaertn.; Fig. 6). (Anonymous, 1977), that name should Cabinet, Vol. 8, Tab. 701 (1827). Image courtesy Missouri Botanical Garden, Population samples of L. laevigatum take priority. A note outlining this www.botanicus.org. grown at Landcare Research (Lincoln, matter was included by the registrar (Lawrie Metcalf) on a copy of the Leptospermum grandiflorum is an New Zealand) were severely damaged cultivar registration form held by the attractive and hardy species with by cold and died out within a few RNZIH. Elliot and Jones (1993) point white, sometimes pale-pink flowers years. In contrast, plants of the similar out that L. ‘Flamingo’ is the name and grey-green leaves. It is sometimes and closely related L. coriaceum by which this selection has become known as the showy tea-tree due to (F.Muell. ex Miq.) Cheel (the green better known. its large flowers and as the autumn tea-tree) have thrived since they were planted in the early 1990s (Warwick

16 New Zealand Garden Journal, 2012, Vol. 15(2) Another cultivar of L. laevigatum another widely cultivated species (typically 8–12 mm in diameter) that is L. ‘Compactum’. As the name (Thompson, 1989; followed by Elliot are usually white and rarely pink. In suggests, this selection has a dense and Jones, 1993; Griffiths, 1994; the wild, it is found in north-eastern growth habit, seldom exceeding 1 m in and Lord, e.g., 1999). Horticulturally, New South Wales and south-east height. L. ‘Compactum’ is available in the name L. citratum has been used . The species is of the UK and the USA. Elliot and Jones rather loosely for leptospermums limited availability in the UK (RHS (1993) state that L. ‘Compactum’ with lemon-scented foliage, such as Plant Finder online) and may tolerate is sometimes grown in the USA as L. petersonii (sometimes incorrectly moderate frost but is probably better L. ‘Reevesii’. Indeed, the USA nursery spelt “L. peterseni”) and L. liversidgei suited to warmer climates. catalogues that I have seen use the R.T.Baker & H.G.Sm. The name In Australia, the cultivar L. liversidgei name L. ‘Reevesii’ more frequently L. lanigerum ‘Citratum’ was listed ‘Mozzie Blocker’ has Australian Plant than L. ‘Compactum’. Each name as not validated in Lord (1995) and Breeders Rights protection (PBR to was listed separately in the Sunset redirects to L. petersonii in the RHS Austraflora as ‘BY11’; accepted 4 Western Garden Book (1995, 6th ed.), Plant Finder online. I am uncertain November 1997). L. ‘Mozzie Blocker’ and both names were combined as of the correct species to which this has soft pink coloured flowers that L. laevigatum ‘Reevesii Compacta’ in cultivar belongs, and the Latinised (from the PBR documentation) may the Suncrest Nurseries Catalogue (A cultivar usage of L. ‘Citratum’ may not be larger than typical for the species guide to ornamental plants for coastal be permissible under the International (13–18 mm diameter). It was selected California with cultural notes, M. Nevin Code of Nomenclature for Cultivated from two generations of seed grown Smith, 1996). Plants (ICNCP). from open pollinated plants by William (Bill) Molyneux, of Dixons Creek, (woolly tea-tree) Victoria. L. ‘Mozzie Blocker’ was Leptospermum lanigerum (Aiton) selected primarily for higher levels Sm. (Fig. 7) is commonly called the of citronellal, the main component woolly tea-tree, after the dense hairs that gives citronella oil its distinctive that cover the young stems and lemon scent. Citronellal is known to leaves. This variable species has be an effective mosquito repellent. grey-green leaves and white flowers “Mozzie Blocker”™ is a most effective (about 15 mm in diameter). In the wild, marketing name and has ensured the L. lanigerum is widespread in damp widespread success of this cultivar. It areas of South Australia, New South was first sold in Australia in September Wales, Victoria, and Tasmania. It was 1997 and is also available in New first cultivated in England in 1774, Zealand. Nurseries recommend it from seed collected in Tasmania. for growing in containers on decks, Today, there are several forms grown balconies and around pools and in the UK that have been ascribed to outdoor eating areas. However, I do this species, and a few are surrounded not know how effective in practice any by taxonomic and nomenclatural reputed insect-repellent abilities would confusion. be. Leptospermum lanigerum ‘Wellington’ Leptospermum macrocarpum was raised and named by Graham Fig. 7 Botanical illustration of Leptospermum Leptospermum macrocarpum (Maiden Hutchins in 1985, from seed lanigerum in Loddiges, C., The Botanical & Betche) Joy Thomps. is a showy collected from Mount Wellington, Cabinet, Vol. 12, Tab. 1192 (1827). Image species that deserves to be more Tasmania (County Park Nursery courtesy Missouri Botanical Garden, widely cultivated. In the wild, it is www.botanicus.org. information sheet 17–19, 1989; rather variable and restricted to a Graham Hutchins, pers. comm.). In A further selection of L. lanigerum small area in the Blue Mountains, the same year, Hutchins obtained is grown in Australia. L. ‘Pendulous’ New South Wales (Thompson, 1989). plants from a New Zealand nursery originated from seed probably This species is named after its large labelled “L. citratum”. Realising that collected in Tasmania. As the name seed capsules of about 20 mm in this name was not currently used suggests, it has arching or pendulous diameter. Flowers are also large (15– by botanists, Hutchins re-identified branches (Elliot and Jones, 1993). 30 mm in diameter), and colour ranges and distributed material in the UK as from greenish-white, yellowish, pink, to Leptospermum liversidgei (lemon- L. lanigerum ‘Citratum’. In this way, dark red. Leaves are usually broadly scented tea-tree, olive tea-tree) Hutchins differentiated between the elliptical and up to about 35 mm Leptospermum liversidgei R.T.Baker two selections he sold. However, his long. This species has previously & H.G.Sm. is a compact and upright approach also created difficulties. been known as L. lanigerum var. shrub that grows to 2(–4) m high. Botanically, L. citratum Challinor, macrocarpum Maiden & Betche. Its dense, bright green and narrow Cheel & A.R.Penfold is an early leaves are strongly lemon-scented. Similarity of floral and vegetative synonym for L. petersonii F.M.Bailey5, L. liversidgei has small flowers characters leads me to conclude

5 Thompson (1989) recognised two subspecies of L. petersonii – var. petersonii (often with lemon-scented leaves) and var. lanceolatum Joy Thomps. (without a distinct lemon odour). Bean (1992) reinstated L. amboinense and transferred L. petersonii var. lanceolatum into synonymy with it.

New Zealand Garden Journal, 2012, Vol. 15(2) 17 that a cultivar known as L. ‘Green Part Two). Both selections were A selection of similar name and Eye’ (Fig. 8A–B) is a selection of named after the green in appearance is L. ‘Copper Sheen’. L. macrocarpum. It is definitely not a the centre of each flower. This is the most common Australian selection of L. rotundifolium (Maiden Leptospermum grown in New Zealand, Leptospermum morrisonii & Betche) F.Rodway ex Cheel as popular for its rapid growth, bronze Leptospermum morrisonii Joy Thomps. claimed in a New Zealand nursery coloured foliage (Fig. 9A) that is a shrub or small tree native to catalogue (Matthews’ Nursery Cat., contrasts well with the creamy-green/ central coastal and tableland areas 1990). L. ‘Green Eye’ has greenish- white flowers, and (like several other of NSW. It has relatively long, narrow, white flowers, coppery coloured foliage Australian species and cultivars) soft and shiny leaves (15–35 mm or (that intensifies during winter months), resistance to the pest that more in length), greenish cream or and a low-growing habit (New Zealand causes maˉnuka blight in Australasia white flowers (12–15 mm in diameter) Gardener, April 1986). Interestingly, (e.g., Derraik, 2008). Some and corrugated bark. L. morrisonii was it is one of the few leptospermums New Zealand nurserymen suggest described as a new species by Joy that have strongly scented flowers. that L. ‘Copper Sheen’ is slightly more Thompson in 1989. Several cultivars of In some New Zealand nursery frost tender than most L. scoparium it are available with attractive coppery catalogues (e.g., Wilsons Nurseries cultivars, although 5 m tall mature or purple young foliage that contrasts Ltd., Hastings, 1982; Matthews’ plants that I know of (cultivated in well with the dense, deep-green, older Nursery, 1990; Blue Mountain Canterbury, South Island; e.g., Fig. foliage and whitish flowers. However, Nurseries, 1993), the cultivar name 9B–C) have shown little, if any, sign of these cultivars have not always been has been corrupted to “Green Ice”. frost damage since they were planted assigned to the correct species. These catalogues also use a common in the early 1990s. L. ‘Copper Sheen’ name “Tasmanian manuka”. This Leptospermum morrisonii ‘Burgundy’ was raised in New Zealand by the late common name is doubly misleading; is a cultivar with dark purple foliage. Mike Geenty (formerly of Hamilton maˉnuka is usually reserved for It was found from Falls Creek near City Council). In 1976, seed labelled New Zealand L. scoparium, and Jervis Bay, NSW by Peter Ollerenshaw “L. nitidum” was imported from the if L. ‘Green Eye’ is a selection of (pers. comm.) of Bywong Nursery in Royal Botanic Gardens, Sydney, L. macrocarpum, it is a species not December 1991. L. ‘Burgundy’ has and germinated at the Hamilton City native to Tasmania. white flowers and grows to about Council Nurseries. Seedlings were 3 m tall. It is currently available from relatively uniform except one that had several Australian nurseries. dark foliage. This plant was grown on for evaluation and first flowered in Leptospermum ‘Copper Glow’ is 1980. Cuttings were initially distributed named after its shiny copper-bronze in New Zealand, to Richard Ware coloured foliage produced on new (Plant Production, Napier) and Noelyn shoot growth (Australian Plants, Parr (formerly of Lyndale Nurseries, March 1992; Cornford, 1996). This Auckland). Ware used the cultivar selection was brought into cultivation name “Pacific Flame”, but Parr named by Australian horticulturist Don Ellison, A the same clone “Copper Sheen”. who harvested seed from one isolated Agreement between the raiser and stand in the wild, and distributed it to growers was then reached that various seed merchants. L. ‘Copper the only cultivar name to be used Glow’ grows reasonably true-to-type would be L. nitidum ‘Copper Sheen’7 when propagated by seed (Ellison, (Geenty, 1992). This cultivar is 1999; Don Ellison, pers. comm.)6. registered with the Royal New Zealand Some have claimed L. ‘Copper Glow’ Institute of (RNZIH). to be a selection of L. polygalifolium However, it clearly is not derived B Salisb. (syn. L. flavescens Sm.) (e.g., from L. nitidum Hook.f. as stated Fig. 8 Leptospermum macrocarpum ‘Green Cornford, 1996). Warwick Harris also on the RNZIH cultivar registration Eye’ growing at Landcare Research, Lincoln, stated this (Harris, 1993a), but his re- New Zealand. A, young plant with coppery form. It has been suggested that examination of New Zealand plants led coloured winter foliage. B, close-up of flowers. this New Zealand raised cultivar Photos: Murray Dawson. him to suggest that L. ‘Copper Glow’ belongs to L. polygalifolium Salisb. may instead belong to L. morrisonii Leptospermum ‘Green Eye’ is var. polygalifolium (Edwards, 1992; (Warwick Harris, pers. comm.). available in Australia and New Harris, 1993a), and several nurseries This view is supported by its listing Zealand, where it is relatively cold in New Zealand are currently in the Australian Plant Name Index hardy in cultivation. This cultivar is selling plants under the name as L. morrisonii ‘Copperglow’ (but different to the interspecific hybrid L. macrocarpum ‘Copper Sheen’. note the orthographic variation of the raised and distributed in England However, I am of the firm opinion that cultivar name). Although perhaps not by Graham Hutchins, who gave it is a selection of the closely related as widely cultivated now, L. ‘Copper his selection the very similar name L. morrisonii – the description in Glow’ is best known in Australia. of L. ‘Green Eyes’ (discussed in Thompson (1989) is a better fit with the plants that I have examined.

6 Unlike more derived cultivars of Leptospermum that should be maintained only through vegetative (usually cutting) propagation. 7 The names L. ‘Coppershine’ (e.g., New Zealand Gardener, April 1986 & April 1988) and L. ‘Copper Shine’ (e.g., Matthews’ Nurseries Catalogue, 1989, 1990, 1992, 1993) are orthographic corruptions of L. ‘Copper Sheen’.

18 New Zealand Garden Journal, 2012, Vol. 15(2) To add to the confusion, there appear Another selection of L. morrisonii is used in the horticultural sense, to be two separate selections in L. ‘White Opal’. It has been available treating L. cunninghamii (hort.) as Australia and New Zealand that share from the Australian nursery trade since a synonym of L. lanigerum ‘Silver the cultivar name “Copper Sheen”. 2006 or earlier but I do not know of its Sheen’. More recent editions of the The Australian Cultivar Registration origins. RHS Plant Finder (from Lord, 1995) Authority hold records of a herbarium list L. ‘Silver Sheen’ as a cultivar of Other tea- with coppery or specimen labelled L. nitidum ‘Copper L. myrtifolium, and treat the name dark coloured foliage include Sheen’ dated 4 May 1966 (received L. lanigerum ‘Cunninghamii’ as a L. macrocarpum ‘Green Eye’, from Melbourne), and also cite a synonym of L. myrtifolium with no L. wooroonooran F.M.Bailey (a listing in an Austraflora Nursery cultivar status. rare species confined to mountains Catalogue dated 1978. These records in North East Queensland and predate the release and naming of the occasionally cultivated), and several New Zealand cultivar. Elliot and Jones New Zealand L. scoparium cultivars (1993) state that the cultivar formerly (e.g., L. ‘Nanum Rubra’, L. ‘Nichollsii known in Australia as L. nitidum Nanum’, L. ‘Red Damask’ and L. ‘Red ‘Copper Sheen’ is a selection of Falls’). L. macrocarpum (Maiden & Betche) Joy Thomps. but Wrigley and Fagg Leptospermum myrtifolium (1996) consider it to be a selection of (myrtle tea-tree) L. turbinatum. The correct identity and name of the taxon widely cultivated in the UK as “L. cunninghamii” has been Fig. 10 Chromosomes of Leptospermum problematic. In recent years, it cunninghamii (hort.), 2n = 44. has been variously placed under Photomicrograph: Murray Dawson. L. lanigerum and L. myrtifolium by Representative material that different authors. Thompson (1989) I have examined shows that listed L. cunninghamii S.Schauer as L. ‘Cunninghamii’ and L. ‘Silver Sheen’ an early synonym of L. myrtifolium are different from one another, and Sieber ex DC. In support, Elliot and that neither is related to L. lanigerum. Jones (1993) stated that L. myrtifolium I agree with Elliot and Jones (1993), was introduced into England in 1824 who consider that material grown in (also as L. thymifolium Hoffmanns.) the UK as “L. cunninghamii” should and is currently often grown in the correctly be referred to L. myrtifolium. UK as L. cunninghamii. On the other L. myrtifolium has white flowers hand, Bean (1973) tentatively included (7–11 mm in diameter) and grey-green “L. cunninghamii” under L. lanigerum, leaves, and grows wild in New South A but noted that it differed from other Wales and Victoria. L. myrtifolium cultivated material of L. lanigerum is one of the few tetraploid species, that was more typical of the species. with 2n = 44 chromosomes (Dawson, Significantly, Bean (1973) commented 1987, 1995). Significantly, my that “it is difficult for the non-botanist to previously unpublished chromosome believe that these two leptospermums count of L. cunninghamii (hort.) is belong to the same species”. To also tetraploid (2n = 44, Fig. 10), distinguish between them, and to providing further evidence that the provide a link with the earlier name, two taxa are coextensive (i.e., they B L. lanigerum ‘Cunninghamii’ has been contain the same members and no used in the UK (e.g., the Plant Finder, others). I am less certain of the true various years). However, this Latinised identity of L. ‘Silver Sheen’ – its foliage cultivar usage may not be permissible resembles L. trinervium (Sm.) Joy under the ICNCP (similar to the Thomps., a species that has been situation for L. lanigerum ‘Citratum’). If in cultivation in England since 1795 it is justified at all, the cultivar epithet (under various names), or it is perhaps could perhaps be shortened from of hybrid origin. “Cunninghamii” to “Cunningham”. C Leptospermum nitidum To further complicate matters, (shining tea-tree) and L. turbinatum Fig. 9 Leptospermum morrisonii ‘Copper the Hillier Manual of Trees & (Grampians tea-tree) Sheen’, a New Zealand raised cultivar. A, (6th ed., 1991) stated that young plant growing at Landcare Research, Leptospermum nitidum Hook.f. is Lincoln, New Zealand, showing intense L. lanigerum ‘Silver Sheen’ is a cultivar endemic to Tasmania. It is a compact bronze-coloured foliage. Photo: Robert selected from material previously shrub that can grow to 2 m tall. It has Lamberts. B, mature tree growing at the grown as L. cunninghamii. Lord narrow leaves that are up to 20 mm Canterbury Agriculture and Science Centre, (1993, 1994) and Griffiths (1994) Lincoln, New Zealand. C, close-up of flowers, long and white flowers (usually 15 mm same plant as Fig. 9B. Photos: Murray differentiated between L. cunninghamii in diameter) with green centres. Dawson. sensu S.Schauer and L. cunninghamii

New Zealand Garden Journal, 2012, Vol. 15(2) 19 Leptospermum turbinatum Joy Leptospermum polygalifolium into synonymy with L. polygalifolium Thomps. is a similar species and Several outstanding and floriferous Salisb., within which she recognised often confused with L. nitidum. It cultivars have been traditionally six subspecies. Her treatment may has been in cultivation for many assigned to L. flavescens Sm., not adequately reflect the variation years under the name L. nitidum including L. ‘Cardwell’, L. ‘Kemp’s in this group, and creates difficulties (Fig. 11A–C) but separated as a Aldgate’, L. ‘Pacific Beauty’ (at times when attempting to assign subspecific new species by Thompson (1989). sold in Australia as L. flavescens ranks to some of the cultivars. L. turbinatum can be distinguished ‘Prostrate’), L. ‘Pacific Flame’, Perhaps it is best to follow the advice by the conical bases to the fruit L. ‘Prolific Pearl’, L. ‘Purpureum’, of Elliot and Jones (1993), who capsules (instead of the broadly and L. ‘Tully Falls’. Most of these state that “Subsequent research has rounded or flat bases in L. nitidum). selections were raised in Australia, resolved that although some of these L. turbinatum is a spreading shrub and some, such as L. ‘Pacific Beauty’ subspecies were distinctive there was that grows 1–2 m tall and 1.5–2.5 m (Fig. 12), are probably too tender for strong evidence of intergradation. across with white flowers (25 mm in general cultivation in cooler climates Therefore it is recommended that until diameter). It is called the Grampians such as those in the UK or southern research clarifies this complex, the tea-tree because it is endemic to the New Zealand. Brief descriptions for status quo of before 1989 should be Grampians, Victoria. Both L. nitidum some of these cultivars are provided maintained.” and a L. turbinatum can be grown in by Greig (1987) and Elliot and Jones As circumscribed by Thompson heavy shade and are relatively cold (1993). (1989), L. polygalifolium is tolerant. widespread and common, occurring from Queensland to New South Wales. It was apparently introduced into England in 1800 or earlier (as L. porophyllum Cav.).

A

Fig. 12 Leptospermum polygalifolium subsp. tropicum ‘Pacific Beauty’ growing at Landcare Research, Lincoln, New Zealand. Photo: Robert Lamberts. A B

B C Fig. 14 Leptospermum rotundifolium Fig. 11 A low growing Leptospermum cultivated at Landcare Research, Lincoln, cultivated for many years at the New Zealand. A, plant in flower. B, close-up Christchurch Botanic Gardens. It is labelled of flowers. Photos: Murray Dawson. as “L. nitidum”, but is probably instead L. turbinatum. A, mature plant. B, flowers. C, Leptospermum rotundifolium close-up of flowers. Photos: Murray Dawson. (round leaf tea-tree) Due to confusion of species Leptospermum rotundifolium (Maiden names, the cultivar often known & Betche) F.Rodway ex Cheel is a as L. nitidum ‘Flat Rock’ in the US highly ornamental and distinctive should apparently be referred to as species (Fig. 14A–B). The orbicular a L. turbinatum selection. L. ‘Flat Fig. 13 Botanical illustration of leaves are responsible for its common Rock’ was selected from the UCSC Leptospermum polygalifolium (then as name, the round leaf tea-tree. This Arboretum, Santa Cruz. The cultivar L. flavescens) in Curtis’s Botanical Magazine, species is well suited for cut flowers, London, Vol. 53, Tab. 2695, 1826. Image as its vase life is relatively long for grown in the UK as L. nitidum ‘Cradle’ courtesy Missouri Botanical Garden, needs to be critically examined to see www.botanicus.org. a Leptospermum (Bicknell, 1995). if it too belongs to L. turbinatum. It also has one of the largest flower Leptospermum flavescens is a name sizes (20–50 mm in diameter), As mentioned, cultivars originally still commonly used by the nursery with colours that range from white, sold in Australia and New Zealand as industry, although Thompson (1989) cream, pink, to purplish-pink. The L. nitidum ‘Copper Sheen’ belong to subsumed L. flavescens (Fig. 13) purple flower colouration is unique other species.

20 New Zealand Garden Journal, 2012, Vol. 15(2) in Leptospermum and most intense or more in diameter) that have a L. rupestre has been referred to in in the cultivars L. ‘Jervis Bay’ and lavender blush. L. ‘Lavender Queen’ cultivation as L. humifusum hort. non L. ‘Manning’s Choice’. I know of has a spreading habit and grows to Cunn. ex S.Schauer, L. scoparium three other cultivars in this species, 1–2 m across and about 1.5 m tall ‘Prostratum’ hort. non Hook.f., and L. ‘Julie Ann’, L. ‘Lavender Queen’ (Harrison, 1974; Elliot and Jones, L. ‘Prostratum’. and L. ‘Williamsii’. Now recognised 1993; Stewart, 1999). From the Leptospermum sericeum at the species rank, L. rotundifolium descriptions available, L. ‘Williamsii’ (silver tea-tree) was formerly considered a variety was said to have large pink flowers Leptospermum sericeum Labill. has of L. scoparium. Consequently, and to attain 1–2 m in height. It is a restricted distribution in the wild, cultivars have at times been listed apparently no longer available under occurring naturally only to the east under L. scoparium var. rotundifolium that name. of Esperance in Western Australia. Maiden & Betche. There is good potential for This species is commonly called the As the name implies, L. ‘Jervis making further selections within silver tea-tree, after the silvery-grey Bay’ originated from that locality in L. rotundifolium. The species is quite coloured new leaves. L. sericeum New South Wales, the coastal part variable and occurs in a range of is an outstanding species of great of the range for L. rotundifolium. coastal and inland tableland habitats horticultural merit, but unfortunately This selection has purplish-pink in New South Wales. Because of its will not tolerate harsh frosts or heavy flowers (about 20 mm in diameter) unique flower colour, L. rotundifolium clay soils. The flowers are usually and an upright habit that attains 3 m is an important parent in hybridisation pale to bright pink (15–25 mm in in height. The selection is typical programmes (Part Two). diameter) and borne in profusion. of wild material from Jervis Bay Elliot and Jones (1993) comment that (Peter Ollerenshaw, pers. comm.), Leptospermum rupestre Hook.f. “In the late 1960s and early 1970s and has been grown in the UK as is probably the hardiest of all tea- some plants of L. glaucescens from “L. scoparium Jervis Bay form” trees, and plants can survive in the Tasmania were inadvertently sold (e.g., the Plant Finder, 1990, 1995). open for many years in gardens as L. sericeum.” It seems that some Leptospermum rotundifolium throughout the UK (Fig. 15). In the of these misidentified plants were ‘Manning’s Choice’ may have even wild, L. rupestre naturally occurs on imported into the UK. The Hillier deeper purplish flowers. It arose the mountain tops of Tasmania, where Manual of Trees & Shrubs (4th ed., from the former Manning’s Heather it is widespread among boulders in 1977; 6th ed., 1991) and Griffiths Farm, near Santa Rosa, California exposed places (Thompson, 1989). (1994) listed material cultivated in the and appears to be a relatively recent When tested, this species was found UK as being moderately hardy, having selection available from perhaps to be as frost resistant as the most bright green leaves and white flowers, the mid 1990s. This outstanding hardy New Zealand L. scoparium and originating from Tasmania, none cultivar does not seem to be currently populations, and has better summer of which describes true L. sericeum. available outside of the US. cold tolerance (Greer et al., 1991). Leptospermum spectabile Leptospermum rotundifolium ‘Julie Leptospermum spectabile Joy Ann’ (sometimes misspelt L. ‘Julie Thomps. is a distinctive species Anne’) was brought into cultivation worthy of cultivation. It was described in 1976 by a Mr E. Demuth (of by Thompson in 1989, and was Albion Park Rail, New South originally discovered as long ago Wales), from a prostrate population as 1957 from the Colo River gorge, growing at Beecroft Peninsula, near New South Wales (as recounted Jervis Bay. This cultivar has pale- by Harris and Percy, 1988). mauve flowers (about 20 mm in Seed was sent (as L. sp. affinity diameter) and a prostrate growth Fig. 15 Leptospermum rupestre growing at sphaerocarpum) to New Zealand the Edinburgh Botanic Gardens, Scotland. habit of less than 300 mm tall and Photo: Murray Dawson. from the Royal Botanic Gardens, up to 2 m across. It was registered Sydney in 1983, and sown and with the RNZIH under the name Most material available in cultivation planted out at Landcare Research “L. scoparium var. rotundifolium ‘Julie have prostrate, compact growth for evaluation. Within this cultivated Anne’”. L. rotundifolium ‘Julie Ann’ forms, and produce small white population, flower colour ranged from has a similar cultivar name to the flowers (7–10 mm in diameter) that pink to deep red, and growth habit New Zealand selection L. scoparium are relatively short-lived (Thompson, also varied. A seedling with deep-red ‘Julianne’ (Dawson, 1997a, 2009). 1989; Commercial Horticulture, petals and a relatively compact bushy October 1991; Elliot and Jones, habit was selected, propagated from Leptospermum ‘Lavender Queen’ and 1993). The growth habit of this cuttings, and named L. ‘Christmas L. ‘Williamsii’ are historical cultivars species is more variable than that Star’ (Harris and Percy, 1988). of L. rotundifolium. L. ‘Lavender generally cultivated, and may Queen’ is occasionally still found in attain 2 m tall. I have observed Leptospermum spectabile ‘Christmas cultivation, although there may now tall-growing plants from Tasmanian Star’ (Fig. 16) has long, narrow, dark- be several clones sold under this seed collections trialled in England green leaves (20–35 mm in length) name. These plants are named after (at County Park Nursery) and in and large red flowers (of about 28 mm their pale-pink flowers (30–50 mm New Zealand (at Landcare Research). in diameter). The cultivar is named

New Zealand Garden Journal, 2012, Vol. 15(2) 21 after its flowers, which were likened to a Christmas star, with dark-red petals that contrast with a large star-shaped calyx, and that radiate from a broad green receptacle. L. spectabile ‘Christmas Star’ is registered with the RNZIH. Before the species was named, it was sold in Australia as L. ‘Colo River’ (Australian Horticulture, 1987). L. spectabile is relatively new to cultivation and not widely grown. It is rather frost tender and also prone to maˉnuka blight, limiting its cultivation in cooler regions of some countries. However, it has been a useful parent in crossing programmes by Peter Ollerenshaw in Australia and by Warwick Harris A B and Murray Dawson at Landcare Fig. 17 Leptospermum variabile ‘Karo Crimson Pearl’ growing at Landcare Research, Lincoln, Research in New Zealand (detailed in New Zealand. A, plant in flower. B, close-up of flowers and a crimson bud. Photos: Robert Part Two). Lamberts. Huxley et al., 1992; Griffiths, 1994). Flowers are about 15 mm in diameter, L. sphaerocarpum is closely related to are borne in profusion, and have L. macrocarpum and L. spectabile. white petals. The original seed was Leptospermum variabile collected from the southern part of The origin of L. variabile ‘Karo the distribution of that species and at Crimson Pearl’ (Fig. 17A–B) has been an elevated site. Consequently, the documented by Harris (1993a). Seed cultivar selected at Lincoln has shown of a then undescribed species was little sign of frost damage over the collected in 1983 from Point Lookout, years. This selection should be grown east of Armidale, New South Wales, much more widely as it is cold-hardy, and sent to Landcare Research compact, free-flowering and blight- in New Zealand. The species, resistant. It had New Zealand Plant L. variabile Joy Thomps., was formally Variety Rights (PVR) protection from described by Dr Joy Thompson in 1999–2004 and was propagated at 1989. one nursery in New Zealand (Elliot’s Wholesale Nursery, Amberley, Fig. 16 Leptospermum spectabile From 21 seedlings grown on, a ‘Christmas Star’, a cultivar raised at Canterbury; Warwick Harris, Landcare Research, Lincoln, New Zealand. compact, low-growing plant (attaining pers. comm.). As far as I am aware, Photo: Murray Dawson. about 1.5 m tall) was chosen and it has not been cultivated in the UK named L. variabile ‘Karo Crimson (e.g., the RHS Plant Finder online). Leptospermum sphaerocarpum Pearl’. “Karo” is an acronym for Leptospermum sphaerocarpum “Known and recorded origin” that This concludes discussion of Cheel is a species naturally found in has been used to identify material Australian Leptospermum species New South Wales. It has greenish- selected at Landcare Research. that are grown in cultivation and the white to pink flowers (10–20 mm in “Crimson Pearl” refers to the red cultivars that have been selected from diameter) and is frost and drought that are prominent on the them. Part Two will document hybrids tolerant. Although not widely grown, unopened “pearl-like” flower buds. between species and the resultant it has been available in the UK (e.g., cultivars from these crosses.

22 New Zealand Garden Journal, 2012, Vol. 15(2)