image from: http://brookhaveninvasive.com/list-of-invasive-species/ |
So
the Metropolitan Police Force in the United Kingdom bravely set out to speak of
things of which it knows little in the wrappings of that which it knows much.
The Police force set out to offer landscaping solutions to personal security by
presenting a list of 30 ornamental plants that will deter criminal intent. And
from a pure security point of view they did a good job. The list is a mugger's
hell of thorns and entrapment barriers and living barbed wire, and even some poisonous
species for good measure. "Most burglars
are lazy. They look for easy ways of getting into a house or garden (and) by
taking a few simple precautions you can reduce the risk of being burgled and
make your house
and garden more secure", the Tribune report notes.[1]
When it comes to the
invasive species part of the article, there is silence on the issue of invasion
biology which is ironic given the topic is defense of the home(land). Perhaps bamboo
does not run in England, but for unwary Americans, and loyal Canadian subjects
of the Queen, the list is a minefield of ecosystem challenges. Many of the 30 species are indeed
appropriate and useful as ornamental defense of hearth and home, but some are
Trojan horses that should remind would be landscapers of Virgil's immortal line: "Timeo Danaos et dona ferentis".
First on the list is number 5 "Golden Bamboo - Phyllostachys aurea- Very graceful,
forming thick clumps of up to 3.5m high. Less invasive than other bamboos.
Hardy. Young shoots in spring." While it is very true that this extremely
quick growing indestructible species will create a grove so dense nothing can
move within or through it, it is also important to remember that this species
also quickly moves across adjoining properties into parks and natural areas as
well as the neighbors' manicure gardens. The American
Bamboo Society provides a 4 + 4 step plan for removal cheerfully suggesting
how easy this will be by assuming you are removing a small patch of say less
than one acre. It should go without saying that buyers should beware for some bamboos
can form dense, mono-cultural thickets that displace both native and ornamental
species. Once bamboo is established, it is difficult and expensive to remove.
Next up is number 11 - "Purple Berberis - Berberis
thunbergii 'Atropurpurea'- Rich purple foliage. Thorny stem. Medium-sized
deciduous. Any soil sunny position." Barberries are quickly establishing
in eastern North American changing the ecosystems in which they establish
themselves. Barberries are Nature's barbed wire and excellent defense against
human and animal incursions but Japanese barberry does not stay put. Rather it
is dispersed by wildlife and, "...forms
dense stands in natural habitats including canopy forests, open woodlands,
wetlands, pastures, and meadows and alters soil pH, nitrogen levels, and biological
activity in the soil. Once established, barberry displaces native plants and
reduces wildlife habitat and forage. White-tailed deer apparently avoid
browsing barberry, preferring to feed on native plants, giving barberry a
competitive advantage. In New Jersey, Japanese barberry has been found to raise
soil pH (i.e., make it more basic) and reduce the depth of the litter layer in
forests."[2]
Way down the list we find genus
only recommendations such as Aralia with no species designation. Here the
problem is one of imprecision for there are invasive Aralias such as Japanese
Angelica Tree, Aralia elata (Miq.)Seem which can trap the uninformed gardener as well as the unsuspecting
burglar.[3] There is also mention of Mahonia some species of which may be showing signs of invasiveness in the US in certain circumstances.
The unintentional irony is the ending statement, however: "Although they
will take some time to grow, the end result justifies the effort. They should
deter even the most determined burglar." Almost certainly selecting bamboo
will disavow you of any thoughts of sluggish establishment and final solution
through landscape domination. It is always worth remembering that when it comes
to complex systems, simple solutions beget unexpected outcomes; there are no simple
problems, no simple answers and no simple solutions.
[1] The
30 plants that can help protect your home against burglary. Telegraph Media
Group Limited. February 27, 2012. [accessed February 27, 2012] http://www.telegraph.co.uk/news/newstopics/howaboutthat/9108641/The-30-plants-that-can-help-protect-your-home-against-burglary.html
[2] Alien
Plant Working Group. Berberis thunbergii
Barberry family (Berberidaceae). Plant Conservation Alliance. July 7, 2009.
[accessed February 27, 2012] http://www.nps.gov/plants/alien/fact/beth1.htm
[3] Central
Jersey Invasive Species Strike Team (CJISST). Japanese Angelica Tree (Aralia elata). Invasive Plant Fact Sheet.
[accessed February 27, 2012] http://www.fohvos.org/pdfs/factsheets/Aralia%20elata_Invasive%20Plants%20Fact%20Sheet.pdf