Taiwan cherry trees (Prunus campanulata) have been sold by nurseries in in our region for their amenity value since the 1960s. The most significantly produced and popular of the cultivars, P. Campanulata felix jury, is a bright, candy-coloured variety, and was often marketed as a sterile tree. Unfortunately, this variety has been proven to produce fertile fruit, and from late July through to early September, mature trees produce thousands of appealing dark pink flowers that attract pollinators such as bees, bellbirds and tui.
Because Taiwan cherry produces flowers in late winter/early spring, flower fertilisation by pollinators is particularly high. These fertilised flowers produce small cherries with a stony centre, about 10 - 12 mm in diameter that are eagerly sought by birds such as wax eyes, starlings, blackbirds and native pigeons. These birds spread them in their droppings to other areas, such as regenerating native scrublands or forests. Other animals, such as possums and pigs may also spread the seed in the same manner. The seeds have a high germination rate, but unlike other cherry trees, a Taiwan cherry tree has the ability to germinate in low light where it produces a very shade tolerant seedling.
With its characteristic single leader growth form, it is able to push up through over-head cover, eventually producing a cone-shaped configuration. Unlike all other woody weeds in the Nelson area, except perhaps Douglas fir, Taiwan cherry is able to invade not only exotic scrub mixtures, but also native scrublands, where it can over-top native mahoe trees that may also be emerging through this scrub.
In the Bay of Plenty and Northland Regional Council regions, millions of Taiwan cherry trees now dominate emerging shrubland communities and mature forests. Considering that the first naturalised (wilding) record for all of NZ was only in 1988, the rate of spread has been extraordinary.
Both of these councils acknowledge that eradication is now no longer possible and that their only way forward is to try and keep it out of other unaffected areas. Because of the proliferation of Taiwan cherry in these regions, the Bay of Plenty Regional Council has had to list Taiwan cherry as a pest weed only, but do not list it as a control species in their Pest Management Plan. Northland Regional Council list it as a sustained control species only in their Plan, in acceptance that while better control would be desirable, it is simply not feasible in their case.
The Tasman-Nelson Regional Biosecurity Management Plan 2019-2029 lists Taiwan cherry as an eradication species, and has legal powers to assist with achieving this goal.
Joanna Barr, Biosecurity Manager at Northland Regional Council, warns that Tasman should view their Northland Taiwan cherry explosion as “the canary in the coal mine”. She told TDC staff that “If you have the chance to eradicate it, you need to pursue that aspiration with urgency, as there is no going back once it has established in the wild”
Abbie Jury, whose father-in-law was Felix Jury who developed the Taiwan cherry cultivar in their Taranaki nursery, told TDC staff that she is concerned about the spread of Taiwan cherry in the wild and supports the current status in the Tasman-Nelson Pest Management Plan 2019-2029 which bans the sale and propagation of these trees in our region.
The Tasman-Nelson region currently has wilding populations that are being brought under control in Tapawera, Kaiteriteri, Eves Valley, North Nelson and Enner Glyn.
For those who have planted a Taiwan cherry tree as an amenity planting, our biosecurity staff will assist with its removal at no cost to the property owner, and can approve the provision of a replacement tree for each Taiwan cherry removed, up to the value of $75 per tree, after confirmation the pest tree or trees are gone.
Taiwan cherry seedlings are deep rooted and after just one year cannot be hand-pulled. Seedlings can be sprayed with glyphosate (Roundup) when in full leaf. Larger trees can be cut off at ground level, although the stump must be treated with a glyphosate gel to kill the root system. If this is not done, coppicing from the base will occur (forming a new tree). Trees can also be killed by drilling holes in the trunk and filling them with full strength glyphosate.
We are not too late at this stage to attempt eradication, but we need the support and cooperation of our local communities to achieve this goal.
Many years ago, gorse, broom and old man’s beard where once in low densities around the Tasman district too. Back then, no one could ever have predicted the rapid rise and spread of these pest weeds and the impact they would have on Tasman’s environment. Let’s work together, and not make this same mistake again by ignoring Taiwan cherry and allowing it to spread through our forests.
To report a Taiwan cherry tree or for further information phone 03 548 8400 or email us today.