Garden for Pollinators, the choice is clear! Or is it?

 Posted by John Murgel, Douglas County Extension

If you have not yet noticed, June is Colorado Pollinator Month!  National Pollinator week kicks off next Monday.  During this month and beyond, you may find yourself the recipient of a lot of different advice on how to best support pollinators in your garden.  I think all of it is given with the best of intentions; differences, sometimes strong differences, exist.  Truth be told, pollinator (and broader ecosystem) support by human activities is an area of active research and practical conclusions are difficult to draw.  To quote Dave Armstrong, professor emeritus at CU-Boulder, “Ecology is not rocket science, it’s harder.” 

 

Native Bees are cuter than you think!

Here’s a conundrum perhaps not unfamiliar to many Colorado gardeners:  should I plant only natives, from local seed sources? I hear this recommendation (sometimes presented as an imperative!) frequently.  Most of my garden is a mix of non-native and “native” plants.  I put native in quotations because I have collected exactly ZERO of my plants from wild seed.  I stand by this decision—having thousands of gardeners added to the list of seed predators seems like a great way to drive wild populations of native plants to extinction.  So out the window goes “local population source” for my natives.  That will lead a conscientious gardener to the risk of genetic material from my "cultivated natives" getting into the wild populations nearby, at the risk of reducing the wild population’s fitness with “weak” domesticated genes.  At least there’s little risk of a non-native plant doing that!

 Perhaps I shouldn’t worry too much about gene flow.  After all, the “natives” I’m growing aren’t all native to my zip code, or even to my county.  Many are “Colorado natives,” or natives from the Western US, chosen more for drought tolerance than for their geopolitical pedigree.  Many true natives from undisturbed places around my home would shrivel on a day like today with the reflected heat and other challenges associated with highly modified, man-made landscapes. At least my questionable natives and non-natives have flowers to visit!

A mixed native and non-native planting

 Maybe I should plant a tree to help shade that hot landscape.  A little cooling provided by all that transpiration wouldn’t hurt either to mitigate the urban heat island effect!  Trees don’t naturally grow in my neck of the woods, so “native” goes out the window immediately.  I’ll have to water a tree, too.  But if the house is cooler naturally, the carbon-cost of cooling it with electricity on a day like today will be less.  Mitigating climate change would help pollinators, right?  What’s the “greenest” choice?  Decision paralysis seems inevitable—how to make the right choice!?

Native bee and non-native plant

 Some decisions you might make in the garden are obviously bad for pollinators—putting up butterfly houses, growing sterile, non-pollen producing plants, or liberally using insecticides come to mind.  Many other decisions, though, are good, or at least less clear.  Take the decision to plant flowers.  Should I only grow native plants for the native bees?  Plants with which they’ve co-existed for millennia?  In my garden, all the bees like all the plants—I see non-native honeybees on native plants, and native, wild bees foraging on my non-native drought adapted plants like Eremurus and Salvia.  Bumblebees really seem to like Salvia, with Echium close behind.  Should I remove the non-natives?  I have mixed feelings about honeybees, so where would that leave me?  Which suite of plants is “best”—for pollinators, for water, for climate change?  We may never know.  But don’t let the perfect get in the way of the good.  Grow some flowers, pick plants that grow where you live, and watch the invertebrates!