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)

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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)

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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/)

• 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.

Phragmites – Elderberry rev 05-13-25