Living Architecture Monitor - Green Roofs for Healthy Cities

NATIVEPLANTRESEARCH
NATIVESURVIVORS
Ron Wik
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By Ron M. Wik
The use of native plant species on green roofs is a topic of
increasing interest, especially in the Northeast where architects
want to make buildings that are both “green” and sustainable.
To meet that demand, designers are requesting a palette of plant
material of North American origin. These installations can represent
entire ecosystems by providing food sources and shelter for
birds and insects.
Many North American indigenous plant species are suitable for
green roof installations. These are typically plants that have
evolved in exposed areas, such as mountainous regions. Others
originate in sandy or xeric conditions, where they have developed
strategies to cope with lack of water. In both habitats, survival involves
morphology devoted to water storage or reduction of water
loss. Fleshy leaves and stems are especially useful for plants needing
to cope with drought and high temperatures.
New England Wild Flower Society has partnered with the Massachusetts
College of Art to test the stamina of native plants on the 11th
floor of a building in southwest Boston, Massachusetts. These
sun- and drought-tolerant species were selected primarily from sand
prairie and alpine biomes to cope with the site’s southern exposure
and the sandy media (89 per cent sand; six to nine inches deep).
The plants were watered twice weekly for one-month after planting,
with no further irrigation since. The study began in October 2005.
Antenarria parlinii ssp. fallax (Plantain Pussytoes) and A. rosea
(Rosy Pussytoes) are both low growing (two to four inches) species,
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