Gardening Topic for October 2005
Bring on the Natives

Provided by the Western Massachusetts Master Gardener Association
www.wmassmastergardeners.org.

When we chose to write an article on native plants, we immediately agreed that any discussion of native plants should include information regarding the problems some non-native plants are posing to our plant diversity. It might surprise folks to know that the loss of native plants due to out-competition from certain invasive species of non-natives is the second greatest threat to plant diversity, behind habitat fragmentation. Fortunately, avoiding problematic plants while encouraging our native plants is something every gardener can do to help ensure the diversity of both our gardens and natural areas. We hope to share with you information about some of the beautiful and useful native plants that are happy in open-field habitats and to provide a list of 13 plants that pose the greatest risk to our native plant populations in Massachusetts.

Natives and Friendly Newcomers...

Native plants are generally thought of as having made their home here since before the Europeans arrived. They have evolved and adapted along with the native animals, insects and even microorganisms with which they share their habitats. Europeans brought in many new plants - both the plants they loved to grow in their gardens back home, and the weeds that came in with animal fodder and dung, and even on the soles of their shoes. In most cases, nature accommodated the newcomers. Flora and fauna made adjustments, and the habitats we know and love - fields, forests, and wetlands - are richer for it.

To Know Them... is to Avoid Them!

However, there are plants that were introduced at one time or another in our history that are out-competing our native plants and now pose the risk of replacing them. These non-native, invasive plants often grow easily under a range of conditions, have few natural pests or diseases, have aggressive root systems, and/or produce great numbers of seeds that can be dispersed by birds, water or wind, allowing them to spread into natural areas. The very toughness of these plants, combined with their beauty, makes them attractive to landscapers, gardeners, and homeowners.
The problem arises when they escape the confines of our controlled landscapes and become established in natural areas where they can spread unchecked, in the worst cases crowding out native plants altogether. One result of the crowding out is that the native food supply in the area is changed, putting stress on the wildlife populations dependent on that food source. For instance, the lovely Purple Loosestrife (Lythrum salicaria), once established in a pond or lake, irrigation ditch, or other wetland, replaces native cattails that would otherwise provide food, shelter and nesting habitat for many different species of animals. Our native Swamp Loosestrife (Decodon verticillatus), while perhaps a bit less "showy" than Purple Loosestrife, is an alternative that helps to preserve the health and diversity of these natural areas.

At the end of this article you will find a list of thirteen of the worst offenders in Massachusetts. We encourage you to look around, where you live, and consider replacing an invasive non-native with one of the native alternatives. We can all help to protect the natural balance by helping to prevent a new introduction of an invasive to the wild.
There are organizations like the New England Wildflower Society that make it easy to learn about alternatives to these non-native invasive plants. The New England Wildflower Society website will even help us match the alternatives to our particular planting conditions. The native alternatives are adapted to life in our area, generally don't need supplemental watering once established, provide beauty and diversity to our landscapes, and benefit our native wildlife.
Now Bring on the Natives!

Whether you like the idea of reconnecting with the native plants that make up our natural plant communities, simply want to add a native or two to your garden for fun or interest, or want to help with their preservation, you have plenty of options. Consider your reasons for choosing your garden plants - color, height, drought tolerance, light needs, soil type, and wildlife attraction. For this article, we've narrowed the discussion to plants that thrive in full sun to light shade. We've included plants that like their soil either dry or moist (as opposed to wet), since it's fairly easy to attain these two conditions by either improving drainage or adding organic matter to improve moisture retention. We chose plants that are native to the Northeastern United States, or in a few cases, we reached over into the Midwest. Please make sure you purchase nursery propagated native plants, and not plants that have been removed from the wild!!

The Plants

Let's begin with the hummingbirds! Some of you may already have Bee Balm in your garden. Available in scarlet (Monarda didyma), pinkish or pale lilac (M. fistulosa) or white (M. clinopardia), Bee Balm will grow in partial shade but will flower more profusely in full sun, and prefers average to moist soil. Hummingbirds will begin and end their days at these stunning 3'- 4' plants, and you'll enjoy the fragrance of the foliage each time you brush against it. Hummingbirds are strongly attracted to red and reddish-orange flowers, as well as tubular flowers. Many of the species that catch the attention of hummingbirds will also attract butterflies.

If you're looking for something a bit unusual, try a Bowman's Root (Porteranthus trifoliatus). The attractive toothed leaves of this erect, shrub-like, 2'- 4' perennial are held on reddish stems. White starry flowers appear in late spring or early summer, and are replaced by reddish seedpods for continued interest throughout the summer. Bowman's Root prefers moist soil under partial shade, but is drought tolerant once established and will withstand full sun in our region.
Joe-Pye Weed (Eupatorium species) will certainly make a statement in your garden. Butterflies will thank you for the large clusters of nectar-filled purple or white flowers atop strong 5'-8' tall stems (great to stand up to our heavy summer downpours!). These impressive plants like moist soil in full sun to partial shade, and will spread to form multi-stemmed clumps. But be patient - it takes two years for plants to reach full size!

Another tall native requiring even moisture and plenty of sunshine is the New England Aster (Aster novae-angliae). The purplish flowers with bright yellow centers will catch the attention of butterflies in September. While these plants can reach a height of 6'-7', you may pinch back the tips once or twice a season for shorter, bushier plants. Also blooming in September, Smooth Aster (Aster laevis) has lavender-blue flowers and blue-green foliage. Smooth Aster is more tolerant of dry soil.

Earlier in the season, False Indigo (Baptisia australis) will attract hummingbirds to its spikes of pale blue pea-like blossoms. The late spring flowers give way to showy seedpods that last through the autumn and can be used in dried flower arrangements. Like many natives, False Indigo is drought-tolerant once established. This low-maintenance 3'- 4' shrublike plant with soft gray-green or bluish foliage will eventually spread to form a large clump. Since it has a deep taproot, this otherwise low-maintenance plant does not appreciate being moved. While False Indigo has escaped from cultivation and is now generally accepted as a naturally occurring plant in our region, yellow flowered Wild Indigo (Baptisia tinctoria) is the true native.

Also an early bloomer, Wild Columbine (Aquilegia canadensis) is somewhat smaller, with less showy blossoms, than the hybrids with which many gardeners are familiar. This native with nodding red and yellow flowers definitely benefits from average to dry (or at least well-draining) soil and light shade during part of the day. Columbine will invite the hummingbirds back to the garden in springtime, and is also the larval host for the Columbine Duskywing Butterfly.
Speaking of butterflies, consider the Milkweed family. The fiery orange flower clusters of Butterfly Weed (Asclepias tuberosa) are irresistible to butterflies. Common Milkweed (Asclepias syriaca) is often dismissed as a weed, but if you've ever seen the exquisite, jewel-like green chrysalis of a Monarch Butterfly hanging delicately from the bottom of a leaf, you'd want to keep one or two around in your garden for the sheer possibilities! Both of these milkweeds thrive in full sun and average to dry soil.

Beardtongue (Penstemon digitalis) is another interesting choice for a sunny garden spot, but will also tolerate moist soil and partial shade. Shiny green rosettes of leaves are sometimes tinged with red, and spikes of white or red flowers may reach heights of 3'- 5'.

Three additional natives that grow in full sun to partial shade are Nodding Onion (Allium cernuum), Stokes Aster (Stokesia laevis) and Wild geranium (Geranium maculatum). The tear-shaped buds of Nodding Onion reveal loose clusters of pink flowers in mid-summer on 1'-2' plants.

Also in the 1'-2' range is the beautiful and somewhat drought tolerant Stokes Aster. This prolific early summer bloomer produces lavender-blue aster-like flowers with fuzzy white centers. Hummingbirds will visit the rose-purple flowers of Wild Geranium in late spring.

'Snowbank' Boltonia (Boltonia asteroides 'Snowbank') is the compact form of our native. For up to 6 weeks in the autumn this 3'- 4' rounded plant will light up the garden with an abundance of white daisy-like flowers. Once again, this plant is quite easy to grow when given even moisture. Once Boltonia asteroides 'Snowbank' is established it will tolerate drought, but plant size will be diminished in consistently dry soil.

A much smaller native that deserves a special little corner of your garden is the 8" Blue-Eyed Grass (Sisyrinchium). Actually a member of the Iris family, this grass-like plant has half-inch deep bluish purple flowers with yellow centers held at the tips of flat, pale green leaves. The tender young foliage can easily be mistaken for grass, but you will quickly develop an eye for spotting their soft green color and flat leaves. Blue-Eyed Grass forms small Iris-like clumps.

Native Shrubs will also make a wonderful addition to your garden. We have included 3 here but there are many more to choose from. Bearberry (Arctostaphylos uva-ursi) is a creeping evergreen that makes a nice ground cover in full sun and sandy soil. Terminal clusters of white or pale pink bell -shaped flowers bloom from May to July on trailing plants that have small leathery leaves. The red berries that appear in the fall will attract birds. Lowbush Blueberry (Vaccunuim angustifolium) does well in partial shade and may grow to 2'. The reward is sweet berries in the summer, with a bonus of red autumn foliage. New Jersey Tea (Ceanothus americanus) is a nitrogen-fixing shrub that produces airy clusters of small white flowers. These 3'- 4' shrubs thrive in full sun and average soil. The dried leaves are said to make a delicious tea. New Jersey Tea also attracts a small fly with which hummingbirds feed their young.

For More Information

This is by no means a complete list. Please check out the websites and other sources we've provided for a more complete list and location of nurseries, as well as lots of great information on choosing and growing native plants, and on how to recognize and avoid the invasive non-natives that are threatening our native flora.

13 of the most invasive non-native plants in Massachusetts:

1. Amur, Morrow's, Bell's, Tatarian, and other shrub Honeysuckles (lonicera maackii, L.xbella, L.tatarica)
2. Autumn Olive (Elaeagnus umbellate)
3. Burning Bush or Winged Euonymus (Euonymus alatus)
4. Common and Japanese Barberry (Berberis vulgaris, B.thunbergii)
5. Common and Glossy Buckthorn (Rhamnus cathartica, Frangula Alnus)
6. Goutweed and Bishop's Weed (Aegopodium podagria)
7. Japanese Honeysuckle (lonicera japonica)
8. Japanese Knotweed or Bamboo (Polygonum cuspidatum, Fallopia japonica and its varities)
9. Multiflora Rose (Rosa multiflora)
10. Norway Maple (Acer platanoides)
11. Oriental Bittersweet (Celastrus orbiculata)
12. Purple Loosestrife (Lythrum salicaria)
13. Yellow Iris (Iris pseudacorus)
(The New England Wildflower Society provides a list of native alternatives to these invasive plants.)

Sources for this Article:

Butterfly Gardening in New England Cheryl B. Lowe, New England Wild Flower Society 2000
Projects for the Birder's Garden Edited by Fern Marshall Bradley, Yankee Publishing Inc. 2004
The New England Wildflower Society Guide to Growing and Propagating Wildflowers of the Untied States and Canada William Cullina, Houghton Mifflin Co. New York, 2000
Rodale's Illustrated Encyclopedia of Perennials, Ellen Phillips &C. Colston Burrell, Rodale, PA, 1993
Massachusetts Wildlife No.3 "Hunting the Invaders", pp.28-37, Michelle Robinson, 2004
The Audubon Society Field Guide to North American Wildflowers, Eastern Region, William A. Niering and Nancy C. Olmstead, Knopf, NY, 1979

Helpful Web sites:

www.newfs.org New England Wildflower Society. A Wonderful website for information about native plants.... They have a list of non-native plants and offer alternatives of native plants.
www.wmassmastergardeners.org Western Massachusetts Master Gardener Association. They have a hotline both via phone and e-mail to answer your questions about plants.
www.mass.gov/dfwele/dfw/nhesp/nhesp.htm Massachusetts endangered species website lists of endangered species by county; vernal pool info
Http://hcs.osu.edu/Plantfacts/ good general information about plants,
www.umext.maine.edu/onlinePubs/hempubs/2502.htm gives a list of places to purchase native plants in Maine. Hardiness zone is similar to Massachusetts, 5a & 5b.
http://www.cyberonic.com/~gwlt/invasive.html Greater Worcester Land Trust article about invasive plants in Massachusetts
www.gardening.cornell.edu Fact sheets on ecogardening.
www.nps.gov/plants/alien Information on invasive plants, fact sheets about invasive plants and ranges of where they are a problem.
http://siet.www.umb.edu/conne/jennjim/fjaponica.html Information on Japanese Knotweed/Bamboo.

Books:

Noah's Garden Sara Stein, Houghton Mifflin Company New York, 1993
The Natural Habitat Garden Ken Druse, Clarkson Potter/Publishers, New York, 1994
The New England Wildflower Society Guide to Growing and Propagating Wildflowers of the Untied States and Canada William Cullina, Houghton Mifflin Co. New York, 2000
The Secrets of Wildflowers Jack Sanders Lyons Press Guildford CT 2003

Local Native Plant Nursery:
Nasami Farm, 128 North Street, Whately, MA is the New England Wild Flower Society's Native Plant Nursery. www.newfs.org 413-397-9922

For other articles, check out our archives

Provided by the Western Massachusetts Master Gardener Association
www.wmassmastergardeners.org