Amelanchier Lamarckii in New Zealand Derrick Rooney1
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Amelanchier lamarckii in New Zealand Derrick Rooney1 Amelanchier lamarckii, better but hairs, but the leaves of A. lamarckii collected in the Netherlands and wrongly known in New Zealand are flushed with rich coppery bronze north-western Germany in the 1960s2, as Amelanchier canadensis, is a (Fig. 1) that sets off the flowers to yet it has been grown in Britain and charming small to medium-sized perfection, whereas A. canadensis Europe for perhaps two centuries. garden tree of uncertain origin; it leaves are plain green. Both have Specimens collected from widely suffers from the unfortunate handicap small, sweetly vanilla flavoured fruit separated naturalised stands in of being much more common than the that passes through red before turning Surrey in the early 1890s have been knowledge of its correct name. black when ripe, but opportunities identified as A. lamarckii. It must to taste them are rare because have been cultivated there for much The genus within the Rosaceae to blackbirds and thrushes devour them longer to be so well established then. which it belongs is primarily North ravenously, often before they are fully Today, A. lamarckii is so extensively American, with between 18 and 20 ripe. naturalised in woodlands in southern recognised species in the United England, the Netherlands, and north- States (where there is at least one western Germany that it is almost species native to every state except considered part of the natural flora. Hawai‘i) and Canada. They have a variety of common names there, Two solutions have been advanced including juneberry, serviceberry, for the puzzle of its origin. The first, shadbush, shadwood, snowy and possibly the less likely, is that mespilus, and sugarplum. Elsewhere, A. lamarckii was originally collected two species occur in Asia, one in and brought into cultivation from Europe, and one each in Turkey a small wild population in North and North Africa. All the species are America that has since died out, deciduous woody plants, ranging or was a microspecies (a discrete from small shrubs to tall trees, with population with limited genetic attractive white flowers in spring. variability) that has been absorbed Most of the American species put back into a larger population. The on a colourful display of autumn leaf more likely explanation, however, is colour, but only a few are cultivated. that it is a stable microspecies which As well as A. lamarckii, these include arose spontaneously in cultivation A. laevis, A. canadensis, and the somewhere in Britain or Europe as a round-leafed A. alnifolia and its result of spontaneous hybridisation Fig. 1 Flowering shoot of Amelanchier smaller subspecies pumila, which is lamarckii. Note the copper flush on the young between two unidentified American recognised by some taxonomists as a leaves. species. The rich bronze colour of species in its own right. the unfurling leaves suggests that In the garden trade, A. lamarckii is one parent must be A. laevis. The The name A. canadensis is very usually propagated through cuttings. other is probably either A. arborea familiar in cultivation, but the species Its quality as a garden plant is or A. canadensis with the odds tilted itself has not, as far as I can ascertain, reflected in it receiving an RHS Award slightly in favour of the latter. been grown in New Zealand. Plants of Garden Merit in 1993. bearing this name in garden centres Microspecies of this kind are not As a wild plant, A. canadensis and nurseries invariably turn out to be uncommon in wild populations of is widely distributed throughout A. lamarckii. Superficially the two are Rosaceae. Many have been identified New Brunswick, Quebec, and very similar in summer and autumn, within American species of the genus Nova Scotia in Canada and from but the differences between them are Crataegus and in Europe among New England down to Alabama in clear in spring. Both are small, multi- the Sorbus, both of which are close the eastern United States. But here stemmed (but not suckering) trees up relatives of the amelanchiers. the plot thickens, because although to about eight metres tall. Both have the North American origin, either What makes the mystery of white flowers in showy racemes, but directly or indirectly, of A. lamarckii A. lamarckii (or A. × lamarckii if A. lamarckii flowers are larger, and has never been questioned, it has a hybrid origin is accepted) more the panicles are longer, up to 8 cm not been recorded anywhere in North interesting (and, some might say, from the lowermost flower compared America as a wild plant. It was not confusing) is that the extreme with about 5 cm for A. canadensis. even recognised as a distinct species uniformity of populations in both The unfurling leaves of both species until a German botanist described and Britain and Europe suggests that it is are covered with short-lived white named it from naturalised specimens probably apomictic, i.e., it can produce 1 PO Box 43, Hororata, Canterbury, New Zealand; [email protected] 2 Amelanchier lamarckii was described by Fred-Günter Schroeder in the journal Taxon, No. 17, p. 633 (1968). New Zealand Garden Journal, 2014, Vol. 17(2) 9 viable, true-to-type seed without the of successive stems having matured because of the superficial similarity aid of an external pollinator. This and died. The homestead was built between the two genera. phenomenon is not common, but is between 1910 and 1914. Ring counts This apparent failure to naturalise well known. of other old trees felled in the vicinity widely is a little surprising, given of the homestead since Barrosa The inference from this reinforces the length of time the species (or became part of Castleridge Station the theory that A. lamarckii is a microspecies, or hybrid) has been in early in 2011 show them to have been microspecies that arose in cultivation, the country and the obvious affinity between 90 and 100 years old, so it is possibly from a single individual that planted specimens have for probable that the amelanchier was of seedling. As far as I can ascertain our climate and soils. Clearly it has an age with them. the suggestion that all of its individual something to do with the conditions offspring may be genetic duplicates Curiously, although it must have required for seed germination. My has not yet been confirmed by had plenty of opportunities to do so, own plant, now about five metres tall, molecular biologists. Amelanchier lamarckii has shown little overhangs one end of a large plunge inclination to naturalise in this country, bed in which there are always a few although our climate and soils should pots and troughs of bare soil that suit it. In England its favoured habitat get watered along with everything seems to be the fringes of oak and else, producing what should be an beech woodlands in sandy loam, but ideal seed bed. Yet while it fruits it is obviously adaptable, and has also freely every year, it only sporadically been recorded growing in soils that produces seedlings. In the 20 or so become water-logged in winter. years since it was planted clusters of seedlings have appeared on only It certainly grows well enough in three occasions. None have appeared New Zealand gardens, even old in the “between” years. I have seen neglected ones, and the presence similar patterns of periodic mass or absence of irrigation does not germination in other woody members seem to trouble it. Spontaneous of the Rosaceae, including Sorbus. seedlings do appear within gardens The absence of a suitable mycorrhizal from time to time, but the Flora of fungus is a possible reason for non- New Zealand, Vol IV, published in naturalisation, but I consider this to 1988, recorded only one example of be unlikely because the few seedlings specimens considered to be growing I have saved and given away have wild, collected in 1954 from two trees flourished. One of them is doing well on the fringe of Riccarton Bush, at Castleridge Station in the Lake Christchurch. They were thought to Heron basin, at an altitude of 695 Fig. 2 This old specimen at Barrosa Station, have seeded from one of the many metres. At that altitude, in a basin Mid-Canterbury, shows clear evidence of surrounding urban gardens. A handful successive stems having matured, died, and surrounded by mountains, frosts can of other naturalised examples have been replaced. occur in any month of the year, and been found since then, in scattered air temperatures of -15°C or lower I have been unable to discover localities: one from Wellington, can occur in winter, so Amelanchier when, or from where, A. lamarckii one from Westland, and three from lamarckii is clearly very hardy and was introduced to New Zealand, Southland3. A few of the specimens adaptable, as well as attractive in all but specimens seen in old gardens were initially confused with Prunus, suggest a starting date in the late seasons (Fig. 3). 19th or early 20th century. This means it has probably been in this country for between 100 and 120 years, masquerading in the nursery trade as A. canadensis for most of this time. Its multi-stemmed habit makes it impossible to determine the age of existing specimens by ring counts, so its probable life span in this country is not known. Although not large, the tree photographed (Fig. 2) in the grounds of the former Barrosa Station homestead in the Ashburton Gorge, inland from Mt Somers in Mid-Canterbury, shows clear evidence Fig. 3 Foliage in autumn. 3 Allan Herbarium specimens include two trees on the edge of Riccarton Bush, Christchurch, collected in 1954 and identified by A.J.