Native Plants in the Garden

I had an opportunity to hear Debbie Edelstein (The Executive Director of the New England Wildflower Society) speak yesterday at the RI Wild Plant Society annual meeting.  Her talk focused on the importance of genetics in choosing native plants, and she talked about the endeavor by plant scientists and ecologists to use ecoregions as a basis for studying and classifying flora and fauna.

                There is an increasing amount of dialogue and interest among those in the plant community on the value of using native plants in our suburban gardens and backyards.  The use of native plants, and their role in the garden habitat is actually a fairly complex issue.  Debbie mentioned in her talk that NEWFS personnel are often asked about where, when and how many native plants to use.  The answer they give is… “It depends”.

                The premise that is put forth by many people and organizations is that native plants are much better adapted to our local soil and climate, are important for native insects because of their coevolution, and will help to preserve our native wildlife population.  Doulas Tallamy, in his book Bringing Nature Home asserts that our native plant, insect and wildlife population is in danger unless we transform our suburban yards into native habitats designed for biodiversity.  He contends that a native plant is almost always a better choice than a non-native. 

                On the other side are people like Peter Del Tredici of the Arnold Arboretum, who argues in his book Wild Urban Plants of the Northeast that our landscape is so disturbed that it bears little resemblance to pre-European habitats.  He believes the reason “non-native” or “spontaneous” urban plants become so prolific is because they are better adapted to the altered landscape.  It seems logical that “non-native” plants wouldn’t be so prolific if they weren’t suited to our environment.

                Both sides present compelling facts and theories.  The issue is one that I believe needs to be reflected on by us, as gardeners, as we create garden habitats.  However, as mentioned above the issue is not always so simple.   Here is why:

·         Plant Genetics: As scientists are now realizing, the genetics of a plant can be equally important to its role in the ecosystem, and so a dogwood tree which has been grown from plants collected in Florida will have significant genetic differences from the same plant grown from seeds collected in New Hampshire.  For example, it will not be as cold hardy and will probably flower at a different time. 

·         Seed source availability: At this time, it is almost impossible to get plant material from native seed sources, and as a result the “native” plants that we buy at the nursery are from stock outside of southern New England.   (NEWFS is attempting to remedy this problem at their own , Nasami  Farm nursery, by harvesting and propagating local seed-sourced plants)

·         Native Cultivars: The nursery industry has spent a considerable amount of money developing “new and improved” hybrids of native plants.  Every year there seems to be plants in new colors, sizes and shapes.  These hybrids are generally what are available to consumers, and there has been little research on the impact of hybridized plants in the ecosystem.   An example of a potential negative outcome would be Winterberry plants that are developed for larger berry size so that they are more ornamental – but whose berry has become too large for some birds to use it as a food source.

So, what do we do?  The NEWFS tells people that the over-riding principle that should be used is to “do no harm”.  How can we do that?

1.       Educate yourself about native plants – join the R. I. Wild Plant Society and participate in their walks and talks.  Take classes at the New England Wild Flower Society.

2.       Read and keep abreast of the latest research in the field.  The NEWFS website: http://www.newfs.org/learn  is a good resource as is the RI Wild Plant Society http://www.riwps.org/nativeplantlibrary.htm and the University of Florida cooperative extension website  http://edis.ifas.ufl.edu/ep297

3.       Avoid planting cultivars of native plants if you live near an undeveloped natural habitat, particularly if the planting is part of a restoration project.

4.       Do not use any plant that is known to be invasive in the natural habitat.

5.       If you are planting a native garden to attract wildlife, use plants that are native to the region, and buy at a reputable nursery that is known for native plants.  The RIWPS website is a good resource for this. http://www.riwps.org/index.htm

6.       Try to use plant combinations that would occur naturally in a plant community.  For example, white pine, maple, dogwood, asters, native geraniums, etc. would be part of a forest plant community.  A wonderful resource for this is a book published by the UNH Cooperative Extension, Integrated Landscaping: Following Nature’s Lead