The changing Leyland Cypress Derrick Rooney1 Thanks to a recent discovery in Dallimore recognised the seedlings cypress, Cupressus glabra, growing Vietnam, the long arm of taxonomy as that uncommon occurrence, an about 20 metres from the Nootka is set to reach out yet again with a intergeneric cross, between the cypress that had produced the name change for the Leyland Monterey and Nootka cypresses. original Leyland clones. Two cypress, one of New Zealand's most This meant that a new name, seedlings from this tree displayed popular farm and horticultural shelter incorporating bits of both generic unusual adult foliage and were trees. names, had to be erected. subsequently propagated and named xCupressocyparis 'Notabilis'. Although it did not become widely At the time, the Monterey cypress Later still, in the early 1960s, a Mr known even in England until the was known to taxonomists, as it is Harold Ovens, from Cardiganshire, 1960s and in New Zealand until the still, as Cupressus macrocarpa. collected seed from a Mexican late 1980s and 1990s, when mass However, the Nootka cypress, also cypress, Cupressus lusitanica, propagation techniques were popularly known in the American surrounded by Nootka cypresses, at developed, the Leyland cypress was Pacific North-West as yellow spruce, the Westonbirt Arboretum. Two of first raised by chance way back in was classified in the same false- the resultant seedlings were clearly the 1880s (in 1883 according to some cypress genus as the better-known crossed with Nootka cypress. One accounts and 1888 according to Lawson cypress, and was known as of these, now known as others) at Leighton Hall, Welshpool, Chamaecyparis nootkatensis. xCupressocyparis 'Ovensii', is grown England, from cones picked off a Dallimore coined the name in New Zealand and has become Nootka cypress. Six of the seedlings xCupressocyparis leylandii for the popular, particularly in the North were sent to Haggerston Castle, in Leyland hybrids. Island, where it seems to grow better Northumberland, for planting in 1892. than it does in the South Island. The The clone 'Haggerston Grey' is one Two more clones were selected in "original" Leyland clones, as is now of these seedlings. Dorset in 1940 from a different well known, thrive almost anywhere source: seedlings from a Nootka in New Zealand below the treeline. Nineteen years later two similar cypress growing at Ferndown. The seedlings were raised at Leighton seed was raised at the Barthelemy Dallimore's compound name of Hall from seed collected off a nursery at Stapehill and for some xCupressocyparis for the group Monterey cypress. These were later years the seedlings were known continued in use until about the named 'Naylor's Blue' and 'Leighton only under Stapehill code numbers, beginning of the present century, Green'. 20 and 21. Eventually, the clone that when intensive research, including has become more popular was DNA analysis, by scientists including Despite the unusual appearance and named 'Ferndown'. Two more one in Australia indicated that the vigorous growth of the seedlings they recently named clones, Nootka cypress was closer to the attracted little attention until 1926, 'Castlewellan' and 'Robinson's true cypresses than to the other when they were brought to the Gold', arose in Northern Ireland, false-cypresses. Thus, attention of W. Dallimore, curator of have yellow or yellow-tipped foliage, Chamaecyparis nootkatensis became the British National Pinetum at and are more ornamental than Cupressus nootkatensis. Bedgebury, who described them and utilitarian. arranged for the 'Haggerston Grey' As a result, xCupressocyparis and 'Leighton Green' clones to be In 1956 the research division of the leylandii became plain Cupressus propagated. 'Naylor's Blue', which British Forestry Commission sent a xleylandii, which, if nothing else, grew near 'Leighton Green' on a genetics team back to Leighton Park made the name a lot easier to spell hillside behind Leighton Hall, was to collect seed in the hope that new and pronounce. propagated only after it was felled Leyland hybrids could be raised from by a freak windstorm in 1954. A the original source. They were Now all that is changed again, as a fourth clone, 'Green Spire', remains unsuccessful in this, but they also result of the discovery, far away in less well known. collected seed from an Arizona the mountains of northern Vietnam, 1 P.O. Box 43, Hororata, Canterbury 6 New Zealand Garden Journal, 2004, Vol.7 (1) of a conifer completely new to To accommodate it and its Nootka most of the Arizona cypresses grown science. relative, taxonomists have erected a in New Zealand are raised from completely new genus, named locally collected seed and are The "new" conifer, found by a joint Xanthocyparis, which, literally extensively hybridised, Dr Sturrock's expedition of botanists from Vietnam, translated, means "golden false- trees most likely have a complex Russia, the United States, and cypress". The Vietnamese golden hybrid background which would England, proved after detailed cypress becomes Xanthocyparis explain their variability. taxonomic studies to be the closest vietnamensis, while Nootka cypress known relative of the Nootka cypress. becomes Xanthocyparis And, of course, they have a distant nootkatensis. but undeniable link to the rare golden The Vietnamese tree has hard, cypress of northern Vietnam. yellow-brown, fragrant, fine-grained Whether these discoveries will require timber that is valued highly by local a new Latin name with a touch of residents, which might account for yellow in it for the Leyland cypress why the scientists found large is still not known, but it seems that specimens only on steep ridges in the meantime nurserymen will have where access is difficult. to re-sharpen their spelling pencils for a switch back from Cupressus to "This tree was already rare and xCupressocyparis, which has once endangered when we discovered it," again become a valid name. an American member of the botanical team was reported as saying. Many treegrowers and nurserymen may prefer to dispense with Latin The common name of the new names altogether and simply call the conifer is "Vietnamese golden group Leyland cypresses. cypress". The species is unusual in that mature specimens carry both Predictably, the clones of Leyland juvenile and adult foliage. cypress, as is expected of intergeneric crosses (among which the mule is a classic) have proved to The "Leyland" in Leyland cypress be largely infertile. However, about commemorates the family who owned 20 years ago Dr J.W. (Hamish) the Haggerston and Leighton estates Sturrock, then with the DSIR, found when the original seedlings were seeds on a small number of Leyland raised and propagated. C.J. Naylor and 'Notabilis' cypresses in a trial was managing the Leighton part of planting near Mosgiel, in Otago. the estates when the first batch of About 50 seedlings were raised by seedlings was raised in the 1880s. the DSIR. Dr Sturrock was given After inheriting both the entailed permission to retain the seedlings estates from his great-great-uncle when he retired, and currently has Thomas Leyland in 1892, he moved them growing on his property near to Haggerston (taking the hybrid Rangiora, in North Canterbury. There cypresses with him) and changed his are considerable differences in their surname to Leyland. Subsequently, appearance and vigour. Farm he sold his lifetime interest in Leighton Forestry Association members who Hall to his brother John Naylor, who inspected Dr Sturrock's trees during died in 1906. John Naylor's son, a field day several years ago Captain J.M. Naylor, took over Leighton Hall in 1909 and remained concluded that although it was there until 1931. He was probably the possible the less vigorous seedlings Naylor of 'Naylor's Blue'. Under the had been "selfed" (a very rare modern convention controlling the occurrence in intergeneric hybrids naming of cultivated hybrid plants, of known low fertility) most had the Latin specific name "leylandii" probably been outcrossed to would not be permitted, but as the windblown pollen from other name was in use before the 1950s, cypresses growing nearby (Arizona its continuation is permissible. rather than Monterey cypresses). As The upper and undersides of foliage of the Nootka cypress (Xanthocyparis nootkatensis) New Zealand Garden Journal, 2004, Vol.7 (1) 7.