Wednesday, January 15, 2014

Careful Use of Non-natives in the Prairie Garden

This planting of Asiatic lilies serves to attract attention to the prairie garden from the roadside and is a softer version of the yellow color that is a repeated element in this garden.

Opinions range widely on the use of non-native plants in the prairie garden.  For the most part, non-native plants will not serve as habitat elements in the same way that native plants will. For example, they will not be a place that butterflies can lay eggs or that larva can feed, perhaps.  But most pollinators are not fussy what sorts of flowers provide their nectar, so the adult forms of the flying insects will still benefit.
One of the most critical aspects of this decision is that non-native plants can become invasive pests that reproduce to the point that they crowd out all other plants.  If this happens, a native ecosystem can be diminished or even destroyed. So it will remain a responsibility of the gardener to check first that any non-native plant they are considering using not be among those already known to be problematic.  Many states have their own invasive plant lists and watch lists, so a first step would be to make sure the plant you are considering is not on such a list.  There are other more general lists published by nature organizations such as The Wild Ones, and these should be consulted as well, because if a plant is a problem in any area, you do not want to be the one to introduce it to your area!
One reason to use a non-native plant might be to introduce flowers into the garden in a gap in the natural flowering sequence of your prairie plants, to add a different texture or color than is available in prairie plants, or simply because you have a fondness for a certain plant, or perhaps have heirloom plants that you are trying to perpetuate.  Another good reason is to add a touch of 'tameness' and familiarity to your 'wild' prairie garden to enhance its acceptance by your community.  A familiar plant such as a lily or daylily or peony or poppy to the garden can make people see it as less threatening and as just another perennial garden, and they may begin to ask about the other plants there, the beautiful native plants, that they will then incorporate into their own gardens!
Of course, the use of non-native plants carries with it some responsibilities.  First, one must keep an eye on those watch lists and be willing to remove the plant from the garden if it appears there.  Second, one must keep an eye on their own plantings, and if the non-native show signs of spreading aggressively, it should be removed and destroyed.  If you are not willing to keep that watch and take that action, you should probably not include non-natives from the start.
It can also be beneficial to prevent non-native plants from going to seed.  Deadheading right after flowering is one way to do this, and cutting off all the seadheads before they fully mature is another.  They should be disposed of in a way that will not allow them to germinate, such as in a hot compost pile.