Plant Life of Lynn Woods
Alien Invasive Weeds
by Ranger Dan Small
Please don't try to remove alien invasive weeds without contacting the ranger first!
Volunteer by contacting Ranger Dan Small at 781-477-7123 or by e-mail at
lwranger@shore.net.
What exactly are alien invasive weeds and are they a threat to Lynn Woods? Alien plants are those that are non-native or nonindigenous. Many alien plants are valuable agricultural crops, such as wheat and soybeans. Others are used as ornamentals, including tulips and many of our favorite shrubs. These plants are not able to compete outside of cultivation and pose little or no threat to natural ecosystems. The key word is invasive, as those plants that have a competitive edge over our native flora. Typically, these plants have some or all of the following characteristics: rapid growth and seed production, effective seed dispersal, rampant vegetative spread, and the ability to reproduce by fragmentation of the roots, tubers or stems.
The spread of invasives has been likened to a slow motion explosion. It is slow enough that you don't really notice it and suddenly it is too late. It has been estimated that nearly 4600 acres per day are being lost to colonization by invasive aliens and that they are the leading cause of extinction among endangered native plant species.
Unfortunately, we have invasive weed species in our woods. Most of them were accidentally introduced by the dumping of yard waste. Some, such as Burning Bush and Norway Maples, were purposely introduced as ornamentals. Invasive species that I have observed in Lynn Woods include Purple Loosestrife, Japanese Knotweed, Norway Maple, Burning Bush, Ailanthus Trees, Multifloral Rose, and Phragmities. Three of these (Burning Bush, Norway Maple and Multifloral Rose) do not appear to be widely established and their eradication should be relatively easy. Phragmities is present in all of the swampy areas of the park and eradication is impossible without destroying the wetlands. Healthy, undisturbed swamp ecosystems have been shown to have the ability to compete successfully with this species and hopefully this will be true in our woods. Purple Loosestrife is widely established in the three ponds, especially Birch Pond.
Eradication would be very time-consuming and would probably not be completely successful. Scientists are currently working on biological control methods for Loosestrife and the results are promising.
The last two on the list, Ailanthus Trees and Japanese Knotweed, are by far the most serious. Ailanthus trees will grow in any soil type, reach maturity rapidly, and are prolific seed producers (an estimated 350,000 per tree). They are ideally suited for the recolonization of the burned areas in Lynn Woods. Knotweed spreads by vegetative growth and has the ability to regenerate from tiny fragments of root and stem. It forms uniform colonies with a height of up to seven feet. These colonies completely shade the ground beneath killing all other plant life. If allowed to spread unchecked, it will eventually cover the banks of all of the ponds and colonize and destroy our wetlands.
We took the first steps toward eradicating these weeds last year, but we need more help. However, this is a case where misguided help can result in making the problem much worse. Extreme care needs to be taken when dealing with these plants to ensure that they aren't spread to uninfested areas.
Lynn Woods Wildflowers
by Ranger Pam Snow
(originally published in July 1999 newsletter)
May has been an exciting month for wildflower watching in Lynn Woods. Of course the flower that bears the month's name started things off early. The Canada Mayflower (Maianthemum Canadense) is a short plant with simple leaves and a stalk of tiny white flowers. True to its other common name, Wild Lily of the Valley, this plant is part of the lily or liliacae family and resembles the garden variety of lily of the valley but of smaller size. This plant spreads by underground rhizomes and forms good size mats on the forest floor.
Growing along side it throughout the woods is the Eastern starflower (Trientalis Borealis) which is aptly named for its small white star shaped flower–well, almost star-shaped anyway–it has from five to nine petals. The leaves also create a star-like effect as the "whorl" around the stem framing the flowers. Another starflower is star grass, a yellow star-shaped flower, approximately violet-sized, with grass-like leaves. Speaking of violets, there were lots and lots of them throughout the woods and gardens this spring.
If you haven't done so recently, you should take a walk through the horticultural garden, as well as the Rose Garden, to see what's in bloom! Winnie and Harvey Robinson have been nurturing this unusual woodland garden, which hosts a mix of wildflowers and garden flowers growing amongst a grove of cedars. In the garden and elsewhere in the woods look for showy pink wild geraniums (Geranium Maculatum) with its big lacy leaves, and Columbine (Aquilegia Canadensis), a beautiful red flower which is the state flower of Colorado. A flower often confused with Columbine is Pale Corydalis (Corydalis Sempervirens) which has similar shaped flowers in pink and yellow. Strangely, it is a member of the poppy family, even though it looks nothing like poppy to most of us. The corydalis grows in open rocky areas and is quite common in Lynn Woods. Of course, we can't forget the all time favorite, pink ladyslipper, which is also fairly abundant in these woods.
Two flowering shrubs of note are the chokeberry (Pyrus Arbutifolia, Melancapa, or Floribunda, depending on berry color) and the maple-leaf Viburnum (Viburnum Acerfolium. The chokeberry is new to me but quite prevalent here–how have I missed this in the past? Typical of its rose family heritage, it has five white petals and a pleasing fragrance. It is actually in the same genus as pears. Here in Lynn Woods, it seems happiest in rocky open clearings and is quite short (1-2' tall), but in Maine I have seen it in wet areas growing to about 4'. The maple-leaf Viburnum lives up to its name, with maple-shaped leaves and viburnum-shaped flowers. A lacy white cluster, it is in full bloom in early June.
If you have seen interesting wildflowers, give me a call to let me know what, where, and when you saw them. I'm looking forward to seeing what's to come this year. Last summer, I saw a Cardinal flower (Lobelia Cardinalis), which is a rare and showy sight, along Overlook Trail where the bog bridge was built. I hope to see it again this year. Please remember "to take only photos" (or drawings) "and leave only footprints" (on the trail) so that everyone can enjoy the same sights you do.and do enjoy the sights you see!
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