Since
you are reading my blog on green roofs, I assume that you basically know what
they are, and may know of one in your area.
You may also know about pollinators-those wonderful insects (bees,
moths, butterflies, etc.) that are
essential for production of seeds and fruits of native plants and crops. You may even be aware that pollinators are in
trouble. And if the pollinator populations are in trouble, our food crops are
too…. We may have to start hand
pollinating our veggies and cereal plants!
Let me
briefly discuss what’s happening AND what we can do to help.
As cities and suburbs sprawl, there is less
native land available for these pollinators.
Turf grass really holds no ecological value for the pollinators- they
are looking for flowers with nectar and pollen.
Further, impervious surfaces (rooftops, parking lots, streets) are not
inhabitable for the species either. In
addition to the lack of natural ecosystem habitats, distance between them, and
parasitic mites, pollinators have another challenge.
Research
is suggesting that plants grown with specific pesticides are killing colonies-
either from hives with direct contact during the spray application, or systemic
(plant retains the active ingredient and the pollinators absorb as they contact
the plant). Now, I’ll restrict myself
from completely geeking out, but the class of insecticides is call “neonicotinoids” (think nicotine
for bees) and the active ingredient is Imidacloprid. BayerAg makes this, and is common in many
products you may buy over the counter at a box store: Merit (grub control),
flea and heartworm control for dogs and cats, and Confidor (used on many fruit
trees, commercial vegetables, and ornamentals).
Commercial growers who supply large numbers of ornamentals for big box
stores probably use these insecticides to manage their crops. For
those “green-thumbers” out there: home gardeners, professional landscapers,
Master Gardeners…Anyone who has bought a plant for in their yard or around
their business, we have probably unknowingly been planting harmful plants! Yikes.
Armed
with knowledge you can work to change this in your personal and professional
life. Just start asking the questions at
the garden center “Where do my plants come from? How were they grown?” Consider going elsewhere if you aren’t
comfortable with their answer. As a general rule, grower of natives and
certified organic growers of crops are likely in the clear. Of course, if you start your own seeds, you
have ultimate management control :) Once
you find a garden center that you trust, select plants like Coreopsis, purple
coneflower (Echinacea), rough blazing star (Liatris), and milkweed (Asclepias). These are also good green roof plants when
designed properly!
I am
excited about an upcoming green roof that will be planted soon. We are using natives and wildflowers to cover
a building intended to blend into the existing landscape. There are some shallow areas where we’ll be
growing succulents, too, so this one-acre roof will jam packed with safe food
for our pollinators!
Are
you interested in selecting healthy plants for pollinators on a green roof? Contact AD Greenroof or start
here: http://beelab.umn.edu/About/Pollination/index.htm