Plant Tips

• Designated by the State of Maine as “Severely Invasive”.
• Perennial shrub grows to 10’ in a dense stand; sometimes called “bamboo” because of its segmented stalks. 
• Thickets release chemicals that suppress other plants, a trait referred to as “allelopathy”.
• Common on private properties and along Harspwell’s roadsides.
• Outcompetes native plants and provides limited value for native pollinators and other native wildlife.

• Shrub that typically grows 3-6’ high and spreads to 4-6’ wide
• Produces an abundance of sweetly scented flowers during the waning days of summer, when few other shrubs are in bloom.
• Showy bottlebrush-like flower clusters, typically 3-5” in length, last for weeks.
• Attracts a variety of butterflies and bees with its attractive fragrance. Leaves turn brilliant golden-yellow in fall before dropping for the winter.
• Sturdy native shrub is remarkably adaptable, tolerating shade, variable soil moistures, and salty air, making it a valuable addition to woodland settings and coastal gardens.

• Nannyberry (Viburnum lentago)

• Red twig dogwood (Swida sericea; aka Cornus sericea)

• Designated by the State of Maine as “Severely Invasive” and “Very Invasive”, respectively
• Perennial shrubs formerly planted as accent plants due to red fruits and adaptability to sun and shade conditions
• Thorny branches make it difficult to trim/maintain; provides limited value for native pollinators and other native wildlife
• Re-sprouts, even when cut severely
• Dense growth form allows it out-compete native plants
• Reportedly harbors more ticks than do natives. See https://today.uconn.edu/2012/02/controlling-japanese-barberry-helps-stop-spread-of-tick-borne-diseases/

• Evergreen shrub that typically grows 8-10’ high and spreads laterally; produces large attractive pink flowers during spring and summer
• Good to reclaim disturbed sites and provides cover and shelter for deer, bears, and bird species but does not do well in windy areas.

Photo credit: Becky Gallery
Sweet Fern (Comptonia peregrina)

• Preferable to Rhododendron in windy areas; smaller than Rhododendron; spreads by rhizomes
• Sturdy, sweet-smelling native shrub; Remarkably adaptable. Prefers sunny areas, but tolerates shade, variable soil moistures, and salty air. 

• Mountain Laurel (Kalmia latifolia)

• Northern Bayberry (Morella [fka Myrica] pensylvanica)

Download this Tip Sheet:

Barberry – Rhododendron & Sweet Fern rev 2-10-25

• Designated by the State of Maine as “Very Invasive”
• Differentiated from native maples by early-emerging, broad leaves, with 5-7 lobes, and white sap that exudes from the leaf stem if it is removed from a branch during the growing season.
• Long-lived, during which it produces copious, widely winged, bow-tie like seeds that allow it to become established on adjacent properties.
• Yellow (not red) fall leaves remain attached after most native maples have dropped their colorful leaves.

• Long-lived tree species that have evolved to thrive in Harpswell’s soils and climatic conditions.
• Both of these species produce the red, orange and yellow leaves that brighten our fall days.
• Mature trees exceed 40’ in height, 25-35’ in width and may live over a century.
• In shady areas, also consider striped maple (Acer pensylvanicum) which has pendulous spring flowers and bright yellow fall leaves
  • https://extension.umaine.edu/publications/2561e/

• Red Maple (Acer rubrum)

• Sugar Maple (Acer saccharum)

• Hophornbeam (Ostrya virginiana)

• Yellow Birch (Betula alleghaniensis)

Download this Tip Sheet:

Invasive Norway Maples Out, Native Maples In

• Designated by the State of Maine as “Severely Invasive”
• One of the first shrubs to emerge in spring
• By May 1, flowers are white, yellow or pink
• By late summer, berries are red
• Easily identified when branch is cut and cross
  section shows dark center like a target.

• 10’-25’ tall and wide
• Good erosion control
• Prefers rich loamy soil, but will grow in clay and soils with moderate moisture
• Emerges early in spring with white flowers followed by red or purple berries
• Hosts pollinators and attracts songbirds and bees.

• Black Chokeberry (Aronia melanocarpa)
• Native to Eastern N.America from Canada to south – Can grow up to 8 feet high with a spread of 8 feet. Grows best in moist, well-drained, acidic soils but will tolerate drier sandy soils or wet clay. Particularly good for soil stabilization. Prefers full to partial sun. White flowers bloom in the spring with black berries appearing in the fall and lasting through the winter. Zones 3-8.

• Mapleleaf Viburnum (Viburnum acerifolium)
• Native to Eastern N.America – Grows from 4 to 6 feet high with an equal spread. Grows best in well-drained, mildly acidic soil with average moisture but can tolerate drier soils. Prefers shade to partial shade. Similar to other viburnums, a cluster of small white flowers gives way to dark blue/black fruits that are enjoyed by birds and other wildlife.

Source: extension.umaine.edu/publications/2500e/#shrubs

• Designated by the State of Maine as “Severely Invasive”
  
• Outcompetes native plants
  
• Impacts wildlife and the environment: Saltmarsh Sparrow, for example, breeds only in saltmarshes and cannot thrive in phragmites. Their presence or absence helps us understand if the ecosystem is healthy.
  
• Alters water flow and drainage patterns with dense growth, hence negatively impacting aquatic ecosystems
  
• Inhibits growth of other plants and can alter the soil conditions
  
• Must be controlled early or it’ll be impossible to control later.

• Grows to 10’, can be a hedge or planted solo, good for erosion control
  
• Has beautiful compound leaves
  
• Is excellent nesting site for bees and songbirds
  
• Is beneficial host for many moths that feed songbirds
  Boasts clusters of white flowers in June and July
  
• Forms dark purple berries late summer, loved by birds and used for jellies and juice.

• Swida sericea: Red-twigged dogwood (https://mainenativeplants.org/plant/red-twig-dogwood/)
• Salix discolor: Pussy willow (https://mainenativeplants.org/plant/pussy-willow/)
• Spiraea alba: White meadowsweet (https://mainenativeplants.org/plant/meadowsweet/)

Notes regarding other commonly used plants:

• While Sorghastrum nutans, Indian grass, is native to North America, it grows to 6’ and is very aggressive; beware.
• Members of the Miscanthus family are popular, tall non-native grasses that spread too aggressively and should be avoided.

Download this Tip Sheet:

Phragmites – Elderberry rev 05-17-25

• Designated by the State of Maine as “Severely Invasive”
• Clogs waterways
• Toxic to grazing animals
• Seed capsules have about 120 seeds each, and can germinate even after burning.

• Native to NE N.America
• May-June blooms in full sun to part shade in moist areas
• Benefits caterpillars, pollinators, butterflies, & hummingbirds.
• https://gobotany.nativeplanttrust.org/species/iris/versicolor/

Note: There are no yellow irises native to Maine, but these may satisfy the same color and growing conditions:

• Marsh Marigold (Caltha palustris) is a groundcover with early spring yellow flowers that look purple to bees.

• Golden Alexanders (Zizia aurea) grows 1’-3’ in sun to part shade that hosts 3 caterpillar species with its yellow spring flowers.

• Designated by the State of Maine as “Severely Invasive”
• Leaves of this aggressive vine emerge very early in the spring, then remain very late in the fall, turning bright yellow
• Seed capsules in fall are yellow and orange
• Easily identified by its bright orange roots

• Native to Eastern N.America
• A vigorous climbing vine or luxuriant green ground cover having five leaflets palmately radiating from each leaf stem
• Brilliant red and purple early fall color
• A very vigorous vine that grows well in most soils in sun to shade
• Pollinated by native bees, wasps, ants

• Virgins Bower – (Clematis virginiana): Native to N. America, Shrubby-vine climbs quickly to
  10-20’, fragrant white flowers in late summer, then fluffy seed heads, prefers rich, moist soil,
  in sun to part shade.

https://gobotany.nativeplanttrust.org/species/clematis/virginiana/

• Dutchman’s Pipe – (Aristolochia durior (aka: Aristolochia macrophylla)): Native to Eastern
  US, Picturesque woody vine with 5-8” heart-shaped leaves, twists its trunk around its sturdy
  support in full sun or part shade. Unusual pipe-shaped flower pollinated by flies, then
  cylindrical 3-4’ green seed capsule ripening to dark grey. Host to pipevine swallowtail (blue
  swallowtail) butterfly.

https://www.wildflower.org/plants/result.php?id_plant=arma7

• Designated by the State of Maine as widespread as “very invasive”
• Forms white clusters of June flowers and red clusters of fall berries that are spread by birds and animals
• (Native roses have pink flowers)
• The leaf stem (petiole) is fringed where it attaches to the twig. 

**Note the fringe at the base of the leaf stem in the photo above **

• Eradication by digging is ineffective unless every root is removed

• Native to Eastern N. America
• Virginiana grows to 5-7’, with red-orange fall foliage. Carolina blooms earlier and grows to 3′
• Both bloom pink and grow in dry sun
• Both provide pollen for bees and nesting sites + winter food for birds.
• https://gobotany.nativeplanttrust.org/species/rosa/virginiana/

• Pink Meadowsweet (Spiraea tomentosa): Pink-flowered Spiraea tomentosa prefers growing in sun and with adequately moist soil. Caterpillars of the Columbia silkmoth (Hyalophora Columbia) and many butterflies are attracted to it, helping pollinators to thrive

https://gobotany.nativeplanttrust.org/species/spiraea/tomentosa/

• White meadowsweet (Spiraea alba):White-flowered Spiraea alba grows well in full sun, but wet or moist feet. It’s suitable frown as a hedge or in a meadow garden. The larvae of the Spring azure butterfly (Celastrina ladon) appreciate this host plant for its healthy survival.

https://gobotany.nativeplanttrust.org/species/spiraea/alba/

Native perennial wildflowers to consider for a meadow setting:

• New England Aster (Symphyotrichum novae-angliae or S.novi-belgii)

• Bee Balm (Monarda fistula)

• False indigo (Baptisia australis)