Saturday, October 17, 2009

On the Road Again or Invasives along our Highways

This past August I traveled up and down interstate 95 and interstate 85 from DC to South Carolina and points in between. I made two trips to DC to help one daughter move into her apartment. Early in month I drove to North Carolina to help the other daughter move into her place. Along the highways I saw all sorts of interesting foliage. Trying to make an ID while driving 65+mph isn’t easy. The trip to South Carolina I didn’t drive, so I took the opportunity to look out the windows to try and figure out what plants were along the highway.

I thought that one of the plants was Sumac, Rhus glabra. Seemed there was a lot of Sumac growing along the road. Some of the plants had a flower or berries at the top. I finally figured out that must be Devil’s Walking Stick, Aralia spinosa. Both of these shrubs/trees are native to the United States. Both also form thickets of growth. I was not sure that ALL that I was seeing was in fact one or the other. Again, going down the highway is not the most effective way to make a plant ID.

Fast forward to our trip this month back to South Carolina, another opportunity to look at trees and shrubs along the drive. As we left I thought I forgot the book I was reading. Looking around the car I found a book one of my fellow Master Gardeners gave me titled Nonnative Invasive Plants of Southern Forests. I flipped through the book as we drove along.

Lo and behold, the plant of which I was trying to make identification turned out to be Tree-of-Heaven, Ailanthus altissima, an invasive nonnative. The leave pattern is pinnately compound –very similar to both Sumac and Devil’s Walking Stick. One of the key identifiers was the autumn color. Sumac turns a beautiful bronze red color as does the Devil’s Walking Stick. The Tree-of-Heaven….pale yellow. I was amazed at the thick groves of this invasive.


Devil’s Walking Stick

see how tall it gets?

Continuing down the highway with book in hand I realized another invasive plant that is also within the National Park…Golden Bamboo, Phyliostachys aurea. It was planted as an ornamental years ago and used for fishing poles, now, it is crowding out cemeteries and homesteads as well as in ditches along the highway.

As I looked through the book there were a few more of these thugs from the book along the highway. Kudzu, Pueraria montana --we all know what it looks like. It covers everything in its wake. Skeeter did a great posting on it about a month ago at In The Garden. My photo is from the Yorktown Battlefield. Our National Parks are being encroached upon by this and other invasives. What a nightmare these plants have become.

Last week Debbie at Garden Thyme with the Creative Gardener wrote a great piece on other invasives. I read her posting after I got back from my trip and had decided to write something myself. There are so many plants out there that should not have been planted and now they are spreading by rhizomes, by seeds from birds or animals, by seeds on the wind…it can make a person mad!

There are so many plants that have been planted by the various highway departments that were used for erosion control or ornamental displays at the interchanges. You and I know many of them; we use them in our gardens. Winged Burning Bush (Euonymus alata), Chinese Silvergrass(Miscanthus sinensis), Honeysuckle (Lonicera japonica), Heavenly Bamboo (Nandina domestica) English Ivy (Hedera helix), and I could go on and on. I have listed some wonderful websites where you can go and find what is classified as an invasive in your area.

There are some Miscanthus and Nandina that have sterile seeded cultivars, be an informed gardener. Can you control the wind as it carries a seed? Will you make the birds promise not to eat and deposit the seeds away from where you can manage them?

Before you buy –do your homework! Know what you are buying. Look at natives or sterile varieties. If you have something that is ‘taking over’ perhaps it is next year’s newest member to the list of invasive plants.

National Arboretum web list about classification of invasives.
USDA website with a listing that links to photos and information on specific plants. As I couldn’t take lots of photos as we drove along the highway, please check out this site.
Golden Bamboo is covering our battlefield.


  1. Janet,

    Great posting! The largest Devils Walking Sticks I have ever seen were on Fisherman's Island at the north end of the Chesapeake Bay Bridge. The trunks on several trees are 8 inching in diameter. You have to have a research permit to explore the island, sorry.

  2. Hello,

    What an informative post. I think many of us pass by some of these invasive plants and don't give them a second thought.

    We have Tree-of-Heaven here and it is somewhat invasive, especially in the higher altitudes where the heat is not quite as intense.

    Thank you for a great post.

  3. Hi Janet, this is a great post! Out of everything you featured, I do enjoy seeing the sumac in the fall...up here, the leaves are a bright shade of red right now. However, it is everywhere along the roads, it's too bad it's such an invasive intruder. I learned a lot by your descriptions and information, thanks! Where's your daughter in this area, and the one in NC? My mother and sister just left NC to build in's lovely in NC. Are they working? Or in grad school? Have a great day...I'll be at my sons swim meet for most of the day! The weather is cold and rainy and yucky! Next week they say it'll be in the 60's and 70's--hooray!

  4. Janet girl .. my son takes trips down to S. Carolina to visit friends there .. but I'm pretty sure he doesn't look at the plants and trees like you do ? LOL
    That was a great observation trip for picking these invasive plants out.
    This is the first year Canada .. Ontario to be specific has had kudzu invade our country from yours .. our tough winters haven't stopped it and now what do we do ? yikes !!
    Hey .. where did you get your Delft plate ? Aren't they pretty ?
    PS .. please tell me you weren't reading the book while driving !!! LOL

  5. I love Sumac and have the cut-leaf variety in the front yard, but I am forever pulling out little starts from the garden comingup from the roots, not so much from seeds. When my neighbors are not home I go into their yard to do the same. They do not garden, but I still don't want my tree taking over their yard.

    I have read that interstates and road sides are great vectors for invasive species. It makes perfect sense.

  6. Janet, You've listed the worst invasives for our forests and unfortunately our yards. I've got to add the Vincas, both minor and major, to the list~~they are all over one of our local parks. I love the thickets of sumac and even plan to plant it in one spot in the yard~~where it can fight the vincas for world domination! Btw, I just picked up that book at a nursery. gail

  7. The choices that the highway departments make aren't always the best, unfortunately...

    We have Devil's Walking Stick growing beside our driveway. It is rather picturesque growing in a stand.

  8. Sometimes it's hard to believe that some beautiful plants could ever become a nuisance, but once you've done battle with one that has become a pest, it may never look good to you again. Good reminder that you may not only be impacting your own yard when you plant.

  9. Thanks for the websites!

    The worst invasive here is definitely kudzu.

  10. Good morning! I am very interested in these plants as I have a very hard time identifying them along the road too (except kudzu of course). It has been a bane to the south. Thanks for the link:) This past summer I thought everything with white flowers was elderberry now I realize it may have been some aralia; which I think has spikes. Yikes! I'd stay in the car I think. I am trying very hard to get away from nandinas because they self seed in my garden a lot. A pain. I know about the burning bushes and wish I'd never planted mine. Such pests but ever so pretty and hard to do away with. Maybe now people are becoming more aware of invasives and will use care in the future with planting-myself included.

  11. Hi Randy, I am amazed at the thorns on the Devil's Walking Stick. Wow!! Nasty. I can't even imagine the size of the one you mentioned.

    Hi Noelle, Thanks, glad you found good information. We are all guilty of not noticing some of these, or maybe not being able to identify them.

    Hi Jan, thanks, I enjoy the sumac and from a distance I enjoy Devil's Walking Stick. I give them a pass as they are natives..the Tree of Heaven isn't.
    My daughter that is near you is in Manassas and the other one is in Roanoke Rapids area. Both are teaching. Hooray!! Hope your son won his swim meet.

    Hi Joy, I bet there aren't many that look at plants and trees like me unless they are a gardener too. I can't believe Kudzu in Canada! wow.
    I got my Delft plate(s) in Germany and Holland. I love the Delft pottery.
    :-D...I wasn't driving to SC so it was safe for me to read my book!

    Hi Les, I like the cut-leaf Sumac too. Now that fall is here with the color changes we can see just how many invasives are along the highway....then again in the spring once the Paulownia starts blooming.

    Hi Gail, I listed but a few as you well is amazing to me to see the list. I agree about the sumac...if it will win over the vinca. I argue with folks here about planting Vinca major. Seems to fall on deaf ears.

    Hi Sweetbay, you are correct their choices are not the best. The Devil's Walking Stick is pretty, both the flowers as well as the berries.

    Hi Megan, very true! I used to like the purple flowers of the vinca blooming. now....not!!

    Hi Ginger, hope these websites come in handy. I like the National Arboretum one especially.

    Hi Tina, It was a great posting that Skeeter did. I guess we shouldn't try to ID things as we got by at highway speeds, eh? WE have Nandina here as well, and I am hoping to corral it. The berries drop ....not many are bird food. Think I will be cutting the berries off anyway. I am trying to be more responsible, as I am as guilty as the next person with some of the plants listed on the websites....but not as much now!!

    Hi Phillip, thanks!

  12. Great information (and yes, NC has plenty of wild invasives). There is a NC Plant Rescue and we have our own invasive list.

    My husband and I pulled out invasive variegated ligustrum this year (a standard landscape shrub planted by landscapers, ours included). He planted a few other shrubs that are on the "watch list" but not yet a threat. Someday, we may have to pull those, too. It seems that so many of the plants that nurseries sell to landscape contractors that are ones to watch.


  13. Very informative Janet. I've tried to be a good steward by planting more natives and avoiding the exotic invasives.

  14. This is such a good post. I get frustrated when I'm at nurseries and see things that are very invasive with no warning or that are on the invasives list. We have English ivy growing up everything around here and killing trees and yet I still see it sometimes for sale.

  15. Janet, invasive plants are such a problem. You are right about being an informed gardener. Here, I am battling Japanese climbing fern, honeysuckle, and the bane of my existence - Virginia creeper. Because we do not have the cold weather to knock these back, they can really get a hold on an area.

    Always Growing

  16. Thanks for such an informative post, Janet. The roadsides along the interstates here are bright with sumac right now, and I love their red color. But the Tree of Heaven is another story--we had it at our former house, and it is extremely difficult to get rid of! Mulberry trees/bushes are another plant that seems to pop up everywhere and is difficult to get rid of. I've never seen the Golden Bamboo before, but I certainly noticed the kudzu on our recent trip to Tennessee. I'll definitely check out one of these websites before planting something I'm not sure of.

  17. Your daughter is in Manassas? That's right next door. My daughter went to HS in Manassas...Osbourn Park HS. She, too, plans to be a teacher (when she finishes college). What grade does she teach, and what school? It has to be in Prince William Co...which is where I live! What a riot!

  18. Two that are invasive here are the Popcorn Tree, which people insist on planting anyway and the Chinaberry, which plants itself.

    The only redeeming feature of a Chinaberry is that hummingbirds will abandon sugar-water feeders and head for woods' edge when the Chineyberries are in bloom.

  19. Hi Cameron, We in the south have lots of invasives. Our mild winters are part of the reason. We have a Ligustrum, variegated, in the Learning Garden -- not good. You are right about the plants that nurseries sell to the landscapers.

    Hi Racquel, Good for you, we all should be good stewards.

    Hi Catherine, Each region has some invasives that really stand out.

    Hi Jan, We don't have Japanese climbing fern much around here (that I am aware of) though the honeysuckle and Virginia Creeper are very common here.

    Hi Rose, thanks! I love the red of the sumac too. I really like the websites I listed for clear information in an easily readable form.

    Hi Jan, just sent you an email with more details. Can't believe how close you are to her.

  20. Hi Nell Jean, I read about the Popcorn Tree, but haven't seen any around here. The Chinaberry is also on that list, there are some around here, I am just learning about them and how to make the proper ID. Big world of plants out there!

  21. Janet,
    Although most of these plants are unknown to me there are plenty of invasives here in the West. It is a never-ending battle. Some ag agents here were offering prizes to people who brought in noxious weeds from their property.
    This is a great post, and I can see that you have done some thorough research, Janet!

  22. Hi Rosey, I like the idea of the ag agents getting the community involved with ridding the area of some of the noxious weeds. I try to get the research done thoroughly.

  23. Oh this is so informative, Janet, thanks! We had that tree of heaven, what a misnomer in the backyard of our first house. It was the messiest most awful thing and was cut down to build an addition extending the back of the tiny house as four kids came along. So many of the invasives came courtesy of well meaning landscapers too. Then the birds helped out. I do love the sumacs and noticed their red coats on the trip to NC recently, just brilliant.

  24. Hi Frances, happy you found it informative. I am amazed as I drive around my area to see how many Tree of Heaven there are. Well meaning landscapers need to learn more about from which list to choose a plant. (in my opinion)

  25. As someone who has also spend alot of time on I-95 over the past few years, this was quite interesting - esp. regarding the sumac look-alike. I love sumac (and love it in the fields of Virginia and along a fence in my own SC garden) - but I'm not familiar with the look-alike. I'll have to pay better attention.

  26. Yay! I could leave a comment!! Thanks for letting me know.

  27. Hi Pam, Hi! Once the fall colors really come to their full beauty you will be able to see the difference!


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