Category Archives: Invasive plants

Invasive Species vs. Non-Invasive Alternatives: Part 2

Contributed by Curtis Hawley

In Part 1 of this blog series, we talked about what the term invasive means in regard to plants. Another term that’s commonly used in this discussion is “native,” which refers to a plant that is native to the local environment. This term also can be dissected, argued and debated.

When we say a plant is native to our area, though, how far back are we going? When we go back about 12,000 years to the end of the last ice age, the glaciers that rolled down Route 128 almost certainly obliterated all “native” vegetation up to that point and transplanted them undiscerningly along its way. Let’s put a closer parameter on time: the Pilgrims landing at Plymouth Rock will be our time cap. We have pretty good documentation about the plants that inhabited our area at that time and those that were introduced for various purposes.

Let’s get into another exciting plant showdown, shall we?

Round 2: Japanese Barberry (Berberis thunbergii) vs. Cotoneaster horizontalis

Japanese Barberry & CotoneasterInvasive: Japanese Barberry (Berberis thungerii)

Japanese Barberry is commonly requested – it be quite appealing to the eye! Visual appeal is typically what spurs a non-native plant’s introduction to an environment. Since Japanese Barberry is an invasive species, it can handle all sorts of difficult conditions including deep shade. It can thus outcompete native plant species, dominating edges of woodlands and choking out native undergrowth.

Non-Invasive Alternative: Cotoneaster horizontalis  

There are a few great alternatives to Japanese Barberry, but my choice would have to be the Cotoneaster. If you want a taller form, Cotoneaster divaricatus looks very similar but grows to about 6’ – 8’. I think the Cotoneaster has a very interesting, unique structure. This shrub offers a skilled pruner (ahem) all sorts of possibilities to accommodate a client’s style preference; from formal and tidy to a natural and flowing look to even accommodating water features.

While Barberry’s deep burgundy color certainly gives it much fall appeal, Cotoneaster has game too! Its foliage has a similar burgundy show, although not quite as deep a color. Where it really wins in my opinion is its bright red-orange fruits which appear in late summer and persist into early winter. I’d recommend Cotoneaster to anyone interested in a Barberry with the confidence that they’ll be pleased with its unique look.

Cotoneaster horizontalis

Here are some other great advantages of this non-invasive alternative:

  • Very hardy plant in all sorts of conditions
  • Much broader, year-round interest
  • No thorns! Barberry is thorny, a concern for little ones, 4 legged friends and your local fine gardener tending your gardens
  • Rabbit problems? Cotoneaster is seldom abused by rabbits

In the next and final round of our Invasive vs. Non-Invasive showdown, we’ll highlight a plant not yet technically identified in Massachusetts as an invasive species. Intrigued? We’ll discuss alternatives before it’s classified as such!

Invasive Species vs. Non-Invasive Alternatives: Part 1

Contributed by Curtis Hawley

Inspired gardeners often ask our crew with hopeful expressions: “I was driving down the street the other day and saw this amazing plant, could you get me one of those?” As knowledgeable horticulturists, it’s our responsibility to do some research before we order you the latest garden showstopper. We go through an in-depth list to learn about each plant. This list includes the plant’s sun/shade requirement, moisture tolerance, acidity/alkalinity preference and competition with neighboring plants. During this process, we sometimes learn that a requested plant is considered an invasive species.

When it comes to plants, the term “invasive” can get a little muddied. For all practical purposes, an invasive species is a non-native plant that is introduced to a new environment where it behaves in a rather aggressive manner due to very little competition and/or extremely ideal growing conditions. Although Poison Ivy or Golden Rod can be rather aggressive at times, they are actually not considered invasive species since they’re native plants. Two examples of common invasive species are Oriental Bittersweet and Japanese Knotweed. Both of these species are very aggressive. They’re often found growing on roadsides and quickly taking over areas. We don’t get many requests for Knotweed, though, so let’s talk about some other popular plants that qualify as invasives and some excellent, eye-catching native alternatives.

Round 1: Burning Bush (Euonymus alatus) vs. Viburnum nudum ‘Winterthur’

Burning BushInvasive: Burning Bush (Euonymus alatus)   

We commonly get requests for this shrub in the fall. Admittedly, its month-long bright fiery red display is quite stunning. Outside of its fall showcase, however, I don’t personally find this shrub to be very aesthetically pleasing, and of course because it’s invasive I don’t recommend it! When someone asks for this Viburnum, I like to present my favorite alternative Viburnum nudum ‘Winterthur.’  I think Winterthur outdoes Burning Bush, plus it’s more friendly to neighboring native plants.

Virburnum nudum WinterthurNon-Invasive Alternative: Viburnum nudum ‘Winterthur’   

Winterthur is a native plant, so that’s a great place to start. Not only is a native plant by definition not invasive, but it’s usually not overly aggressive either. But you know what’s even better about native plants? They’re being grown in their natural environment, which means that it’s very likely that the plant will thrive!

Here are some other great advantages of this non-invasive alternative:

  • Much nicer flower show in May/June (Burning Bush has a non-distinct flower)
  • Flowers are followed by a colorful fruit structure that changes from red to blue throughout summer
  • Fall colors feature maroon to dark red-purple
  • Great food source for pollinators
  • Better ornamental shaping from pruning (Burning bush tends to get sheared into “meatballs”)

 

Stay tuned for Parts 2 and 3 of the Invasive vs. Non-Invasive Plant Showdown, including another very popular shrub and one of the most popular plants you can still buy today…

One woman’s treasure . . . is invasive to another!

The definition of an invasive plant has changed through the years: many of our common ornamental plants, trees and shrubs which we have loved for decades have been declared invasive since they are choking out or can choke out our native species. (Click image to view full size) Continue reading