Invasive Species: How Neglect Breeds a Problem

 

Today is the last day of this year’s Invasive Species Awareness week. You might think that native plant advocates would only talk about native plants, but unfortunately the presence and spread of invasive plant species negatively affect populations of native plants. Those of us who care about native plant populations and habitat have to educate people about both native plants and the impact of some exotic, invasive plants.

Photo: Richard Gardner, Bugwood.org

How do exotic invasive plants spread? First someone plants them, but what happens next is what makes them a problem. Their seeds spread: via wind, wildlife, and water. These seeds land in new places and create new populations. This spread may start slowly at first: it is said that Japanese honeysuckle (Lonicera japonica) grew in gardens for years before it made the leap to invasive status. Yet by 2008, this exotic vine had disturbed over 10 million acres, far more than any other plant (including kudzu).

What happens next is the problem: neglect and ignorance. For example:

• People don’t realize an exotic plant has self-seeded into their property.
• Or they notice it but don’t recognize it and decide to do nothing.
• Or they notice, may even recognize it (like the honeysuckle), and decide to leave it (perhaps not realizing its invasive potential).

One plant turns into this over several decades

Years ago, ignorance was easy to understand. Resources to identify plants (“Ask Aunt Mary, she knows plants.”) were few and hard to obtain. Today, ignorance is no excuse. Plant apps can help anyone figure what they have. This is especially important when plants are just becoming invasive in an area; I have watched tree of heaven and princess tree slowly spread into north Georgia, in parks and on roadsides.

Princess tree (Paulownia)

So if you find something and you don’t know what it is, please take steps to figure it out. If you need help in Georgia, there is a good Facebook group, you can always reach out to the Georgia Native Plant Society, and your local extension office can help. Don't be part of the problem, be a part of the solution!

Some of my previous blogs on invasive plants:

Invasive Plants Give the Wrong Impression

Winter Weeds in the South

The Forest Less Diverse

Removing Invasive Plants Makes a Difference

Remove Invasive Plants Early for Best Results

The Sneaky Invasives: Porcelainberry

 

Kudzu is easy to recognize but it's not the worst

A Tree We Can All Celebrate

 

Georgia celebrates Arbor Day on the third Friday in February, but if you missed it, you can still celebrate our native trees and plant new ones into March. Our spring rains and generally cooler weather help trees get established before it’s too hot. I’d like to celebrate a tree that is widespread in Georgia, adaptable to soil conditions, beneficial to wildlife, and beautiful to humans: the red maple (Acer rubrum).

I drove down to Florida recently and was delighted to see the abundance of red maple along the highways and county roads. Many were flowering but some were already making seeds. Both the flowers and the seeds are very beneficial to early pollinators, birds, and small mammals. As a host plant for moths and butterflies, it is 8^th on this list (click here to see them all) and supports at least 285 species.

Red maple's natural range in Georgia

In my own yard, it is flowering now and I spied a small azure butterfly flitting from flower to flower (but too fast to capture a photo!). I’ve written about this tree before from several aspects. Check out these posts and learn more:

Red Maple Takes a Chance – a post about early flowering

Parking Lot Maples – a post about the use of red maple in parking lots (they can take those harsh conditions)

A Fall Profile: Maples – this post talks about the gorgeous fall color of our native maples

February 2024 Moment in Nature

I always appreciate birds in the winter and feel good about putting seed out for them (note: I'm not as generous in the summer). While there are plenty of the same species of birds, it's exciting to spot new ones. Therefore, I was thrilled to see what appears to be a pair of purple finches visiting the feeder, and the discovery was special enough to be my #momentinnature for this month.

This weekend is the Great Backyard Bird Count, which is a fun community science project to do. If you haven't been counting, you have today and tomorrow to do so. If you've got kids or grandkids with you then get them involved; you might just spark a lifelong interest in birds and nature.

Landscape Spotlight: American Holly

Evergreen plants have great appeal in landscaping. They are heavily favored for screening, especially around the front of homes where they used to serve a useful purpose to cover the bare foundations of houses. This article from 1980 downplayed the need for foundation plants over 40 years ago yet still the practice continues. The article provides some useful context for the practice.

In the late 1800’s: large homes were built: custom-built houses with high foundations were in fashion about the same time houses were placed further back from the street and set in an open lawn. In those years, a foundation planting was deemed necessary to hide the foundation and otherwise soften the break between the house and lawn.  

Early front porches, popular for watching passersby and socializing, also reinforced the need for foundation plantings to hide the supporting posts for the porch: “The plants which once were used to hide the open porch railings and lattice work between the supporting posts of houses of that architectural style still exist. This type of ‘left-over’ foundation planting across the front of most residential houses today serves no real purpose.”

Today we find that buildings have beautiful fronts and there is no need to hide support structures. Yet the concept of evergreen trees and shrubs to beautify the area in front of a building persists and so in this post I want to highlight a pleasing arrangement of American holly (Ilex opaca) that I found in a relatively recent group of landscaping.

American holly with Virginia sweetspire (Itea virginica)

This group of 5 American hollies is in front of Milton City Hall, and in the dead of winter they provide a pleasing display of green foliage with red fruit highlights. On the side of the building, there is a grouping of what appear to be Foster hollies (Ilex x attenuata ‘Fosteri’) – a hybrid between two native species: Ilex opaca and Ilex cassine.

The suite of native evergreen trees in the Piedmont area is not as robust as most would like and exotic plants are often used instead. If we can increase the demand for good native choices, perhaps growers will produce more. Ask for native plants when you shop, ask for them to be ordered if necessary, and be willing to wait for the next shipment to come in. They’re worth it.

American holly in front of Milton City Hall

Fickle February

 

Snow in 2016

I find that February is the least predictable month in metro Atlanta. We could have snow as we did in 2020, 2016, and 2014; it might be rainy; or it could be quite nice – as I write this on Feb 2, the groundhog in Georgia has predicted an early spring and the temperature is a pleasant 66 degrees. I walked around outside, looking for signs of spring but there were few in my yard (only one trout lily leaf). Mostly I just saw what the deer have wrought over the last month or so: Christmas ferns munched to nubs, several saplings with broken branches and deer rub, and telltale piles of scat.

My friends (even in metro Atlanta) are reporting early trillium foliage so I’m sure mine will be up soon. If you’re looking for ideas to add early native spring perennials to your landscape, I have some suggestions here.

If you’d like to venture out to see early native perennials, consider a trip to The Pocket in NW Georgia (where plants can be surprisingly early) or to the spectacular Wolf Creek in SW Georgia (according to their page on Facebook, they will open on Feb 8^th this year).

Bring your raincoat, your snowshoes, and some sunscreen. The weather could be anything!

They Won’t Change Their Behavior

 

This is the time of year when the fruits of the exotic Nandina domestica shrub are particularly noticeable and reminders go out from conservation groups to remove the fruits (and even the shrubs) to protect birds. Shrubs like these were recommended in the past to support fruit-loving birds – called frugivores – during the winter. So why now the change to remove them to protect birds?

Cedar Waxwing

The advisement is primarily to protect Cedar Waxwing birds, a Georgia winter resident that sometimes gorges on abundant fruits. The fruits of nandina contain cyanide and other alkaloids. In small quantities, it appears that most birds are not harmed but there have been several incidents in Georgia (Decatur and Thomas County) specifically where Cedar Waxwings have died. It is generally understood that poisoning occurs when the fruit is ingested in large quantities, such as when gorging.

Some people think this harm is overhyped – that the number of reported cases is too low. However, it takes a lot of effort to determine what killed a bird, assuming someone reported the deaths to begin with. So it is very likely that the deaths are underreported. Some people have even suggested it's the birds fault. 

Bottom line: these birds aren’t going to change the way they feed (i.e., gorging occasionally) in our lifetime so using nandina and hoping for a different outcome isn’t a viable approach. We have the big brain. It’s up to us to do the right thing.

Nandina domestica

I should also mention this plant is tracked as an invasive species in Georgia, capable of creating new populations thanks to spread by wildlife. I pull out 2-3 new seedlings per year in my yard; if all 47 homes in my neighborhood also got two new seedlings per year that would be 98 new plants per year in just my neighborhood.

In addition to those two reasons for avoiding this plant, know that if you instead use a regionally native plant, you’ll be contributing to the ecosystem and likely providing more support for birds even if that plant doesn’t have fruit. If you’re planting shrubs specifically for fruit, choose something else.  

There you have it: 3 reasons to get rid of nandina in your garden (or avoid adding it). When we know better, we can do better.

January 2024 Moment in Nature

It's been a cold week here and I've not spent much time outside. Yet even the walk to the mailbox can bring a moment of joy in the nature around us. During this relatively dull period, the sounds of winter birds are more noticeable when there are fewer visual distractions.

One of my favorites is the brown-headed nuthatch. While they are considered year-round residents, I seem to notice them more in the winter and early spring. Their squeaky calls are very unique. They are out and about this week and their busy sounds are my #momentinnature for this month.

If you'd like to hear them, this video on YouTube captures the sound perfectly.