Thursday, April 2, 2009

When Invasives Invade Your Garden

I think we're all aware that each state has a list of invasive species that you are discouraged from planting and in some cases, prohibited from doing so. The main reason non-native invasives are no-nos is because they tend to choke out or inhibit growth of the natives, thereby changing the local ecosystem. Since all living things in nature depend on each other for survival, these changes mean sure death for at least some of our natural inhabitants, including native wildflowers.

Ohio's top ten worst offenders are:

  1. Japanese Honeysuckle
  2. Japanese Knotweed
  3. Autumn Olive
  4. Buckthorns
  5. Purple Loosestrife
  6. Common Reed
  7. Reed Canary Grass
  8. Garlic Mustard
  9. Multiflora Rose
  10. Bush Honeysuckles
A complete list of Ohio Invasive Plants can be found here in a PDF file.

As a home gardener, I'm not very knowledgeable about identifying many of these. Some hybrids with similar names and botanical genetics are sold in nurseries, and even some of the invasive species are sold in reputable garden centers. So what's a person to do?

Familiarize yourself with the names of those plants that are known to be present in your part of the state and don't buy or plant them. Have a look at photos of their leaves and learn about their habits. You may never become an expert at it, but you'll at least know more than you did before and in this way will become a more responsible gardener. The best place to learn about invasives is to visit your state's Department of Natural Resources website.

Let's move on to the problem child living at Our Little Acre. We have a Morrow's Honeysuckle (Lonicera morrowii) at the southeast corner of our property. Romie says we planted it shortly after moving here in 1977. That's more than 25 years before I became a gardener and to be honest, I don't remember planting it. Whether we did or we didn't doesn't matter now; I want it GONE.

So cut it down or dig it up, you say. Oh, if it were only that simple! An invasive shrub that has a 25-year head start doesn't give it up that easily.

When Max's Garden was created in October 2005, my desire at that time was to tame The Monster in the Corner. This large shrub was out of control, so we cut it back severely. I'm not sure if that was a good idea, because for every branch we pruned off, twelve more grew back in its place. And where Romie used a chain saw to remove a couple of large shoots at its base, even more shot up.

I vowed to keep up with the new growth by continually cutting it out, but it was not about to let the likes of me get the best of it. Finally, last fall, I threw a temper tantrum and ordered Romie to get rid of it once and for all. I didn't care how he did it. I just wanted it out of there.

The chain saw came back out, as did the axe. He buzzed and he chipped and he chopped and he buzzed. I kept carrying the branches to the burn pile, which grew higher and higher, hour after hour.

When he had whittled it down as far as he could go, there remained an ugly conglomeration of multiple hacked-off trunks and branches about six inches high. He'd had enough and we hoped the shrub had too.

But oh noooooo...not this thug. Spring is back and so is the Morrow's Honeysuckle.

After doing some online research, I think we're going to resort to chemical means. I'll be looking for Stump Out ®, which when applied to the stump causes it to decompose rapidly.

Some interesting facts about the Morrow's Honeysuckle came to light while I was looking things up. Morrow's Honeysuckle is thought to release a chemical into the soil that inhibits growth of spring ephemerals and the heavy shade it provides inhibits native plant growth.

Many Cedar Waxwings' wax spots in the eastern United States have taken on an unusual orange hue in the last 35 years, a phenomenon that has been attributed to
Lonicera morrowii. The chemical involved in this color change is rhodoxanthin, a red dye found in the berries of Morrow's Honeysuckle. ¹

Sources on Invasives:

Missouri Department of Conservation
Center For Invasive Species and Ecosystem Health
Ohio Department of Natural Resources
Ohio Invasive Plants Council

Jack on the Morrow's Honeysuckle - February 2008



Nutty Gnome said...

Thanks for a really interesting post today - I know the list doesn't apply to me here in the UK, but we have invasive nasties of our own too! I'd only heard of Japanese knotweed - and that is becoming an issue over here too.

Much as it grieves me to resort to chemicals, it does look like it's the only answer to the Morrow Honeysuckle problem. Good luck!

garden girl said...

Yikes Kylee! It's amazing how persistent invasives can be. After I moved here I found buckthorns all over mixed in with the shrubs and about anywhere the lawn mower didn't go - most were still small enough to dig or pull, and thankfully buckthorn is pretty easy to remove even if the plant is already a few years old.

We had some mulberries all over too, and some too big to dig out. I watched them carefully two years ago, cutting off every single new sprout coming from the roots all summer. Finally around July and August they stopped sprouting, and as of last year I think I can say they're officially dead. It was a pain doing that, but removing all the sprouts seemed to do a good enough job that they finally died.

They weren't nearly as big as your honeysuckle though, and I'd probably vote for the chemicals too at this point, or having the stump ground up might do the trick too. Good luck!

Meems said...

Wow, Kylee, that is some kind of stump from a honeysuckle. And who would think an innocent little honeysuckle could be so intruding?

It is kind of frustrating that the tags in the garden nurseries (because here they sell a couple of them regularly) don't read: invasive. Or even: The possibility of invasive... something to help beginning gardeners. Of course many invasives seed themselves easily and spread without any help from unbeknownst homeowners.

Interesting notes about the wax wings.
Meems @ Hoe and Shovel

Dave said...

We have a back fence line where the honeysuckle roams. I want it out of there but I'm not sure I could every get it all! I don't want to use sprays since there are so many trees back there giving us privacy. They say that you can paint an herbicide onto the leaves and have it kill the plant off. I may have to try it!

Lisa at Greenbow said...

OH MY GOSH what a thug. That root/trunk mass is scary.

I have that Japanese Knotweed in my garden. It is coming out today. I actually bought it sevearl years ago at a Master Gardeners plant sale. Who would have thought??

F Cameron said...

What I wish is that retail nurseries would stop selling plants on the invasive lists. The landscapers for new homes don't know that they are planting invasive shrubs all over our area (happened here at my house, too). I have ligustrum and can't afford to rip those out and replace, so we keep the new growth sheared off to keep them from flowering and seeding.


Unknown said...

I have a stand of honeysuckle in my side yard that blocks the view of my neighbor's yard. It's a jumbled mess but I don't mind I'd rather see that than his shed and dog lot.

So how does the old saying go? One gardener's invasive is another's aromatic,blooming hedge :o)

Chiot's Run said...

The garlic mustard is starting to invade our property. We're fighting back by eating it, it's edible and since I need to pull it anyways, we're eating it in salads every night.

Andrew said...

Ack! Invasives are such a problem -- thanks for posting on this. The more people get the word out the better.

If you're still not sure about the chemicals, have you considered smothering? Maybe some jute matting and 3-4 inches of mulch? And of course there's always landscape fabric plus mulch, but the fabric can clog and then your soil can go anaerobic, yada yada... These things are always a dilemma for me. Good luck regardless!

Unknown said...

When i was young someone gave me a purple loosestrife plant. I didn't know what it was at the time. Of course i figured it out and destroyed it immediately. We have a problem with this invasive and someone apperantly thought it was pretty in the swamps and thought i should have some.

thanks for the post.

Connie said...

Wow, that is a baddie! Here's hoping you can eradicate it once and for all.

Becca's Dirt said...

That is a good post Kylee. Very informative. I'll have to look into the list for Alabama.

Kathy said...

We have a lot of invasives on our property. Our bush honeysuckle is Tartarian honeysuckle. I really think the hundred or so on our property all came from the neighbor's landscape specimen across the street. It is huge and the flowers on it are a deep pink. Looks spectacular in the spring, and I'm sure it was planted long before it was known to be invasive. The birds love the berries and I'm sure that's how all ours were delivered.

Mr. McGregor's Daughter said...

That Honeysuckle is one wicked Hydra. You could try covering the stump with heavy black plastic, but the most effective thing I've found is to cut the new sprouts back to nubs, and dab weed killer for brush & woody plants onto the nubs. It sometimes takes repeated treatments, but it eventually kills it completely. Good luck.

Catherine@AGardenerinProgress said...

Very interesting about the waxwings color change. I hope you can get rid of the honeysuckle once and for all!

Gardeness said...

Wow, that thing is ruthless. It did have nice blooms though. I agree that nurseries, often big box stores, aren't terribly responsible about keeping invasives out of their inventory. Thanks for the great reminder that we must be diligent. I, of course, will need to keep a list in my plant buying car!

Pat said...

We have the Japanese honeysuckle. Think it came with something we bought. May never get rid of it.
It is pretty but NOT for the garden.

Gail said...

We have bush honeysuckle, too. Our entire city including the woodlands and parks, every empty lot and shoulder of the road is covered with them.....they are too successful an invasive. Last fall I had a crew remove some of the largest bushes...No way could I afford to do the entire wayback backyard.. You will have to use a woody systemic killer to get rid of that stump. It is a Hydra! gail

Janet, The Queen of Seaford said...

Great post Kylee. That stump is certainly large. Each state has a list of invasives. It breaks my heart when I see all the Kudzu in the woods near Colonial Williamsburg and the bamboo as well. What were they thinking??

tina said...

It's a persistent thug isn't it? Gee I would be totally mad! Yes, it's for sure time for chemicals-maybe some round up and some serious mulch with landscape fabric over the stump to smother it. Good luck!

Kylee Baumle said...

Nutty Gnome ~ We may have different invasives, but dealing with them is a problem we share!

garden girl ~ We have buckthorns around here, too. We see them all the time when we take our walks down to the woods.

Ohhhh...those mulberries! We have a white mulberry that came up in our garden and we should have removed it when it was small, but we didn't know what it was. Now it's pretty big and I may attempt hacking that out, too. It has bright yellow roots, which helps when it comes to identifying its roots (there are two other small trees nearby).

Meems ~ I found that interesting about the cedar waxwings as well.

Dave ~ I've read about that method, too, and will likely do that with our honeysuckle.

Lisa ~ I have a variegated Japanese Knotweed that I purchased two years ago at a reputable Cleveland nursery, in fact, I was told it was one of the owner's favorite plants. It is likely a hybrid, but I can see how it might be invasive. Each spring, it doubles in size as far as ground space goes.

Cameron ~ Yes, I agree!

Sherri ~ I hear you. I'd be the same in that situation, I think.

Chiot's Run ~ I never even thought about being able to eat garlic mustard! If you can't beat 'em, eat 'em! LOL

Andrew ~ I'm not sure smothering would work, but if our other methods don't work, we'll try

flowrgirl1 ~ Oh yeah, the infamous purple loosestrife. I used to have one of those, too, but no more. THAT was invasive in my garden - came up everywhere. It's not THAT pretty and is one of the worst offenders.

Connie ~ I'm hoping the same!

Becca ~ Some of the things on the list are surprising and I'd imagine it will be no different on Alabama's list.

Kathy ~ A hundred! Wow! Well, that's a few too many to try and rid yourself of, I'd say!

Mr. McGregor's Daughter ~ Thanks! We're gonna need it!

Catherine ~ I thought that was really interesting, too!

Gardeness ~ The blooms were actually not very flamboyant, because the foliage was so prominent. But the bees did love them! Plant buying that!

Patsi ~ We actually have what I think is a Japanese honeysuckle and have had it for years. I'm not even sure where it came from, but it hasn't proven to be invasive here on our property. However, who knows how many birds have eaten its berries and "planted" them elsewhere?

Gail ~ We'll get it one way or another!

Janet ~ I think people have good intentions when these things are first introduced, but then things don't go as planned!

tina ~ Round-up has been an option we're considering.

Wayne Stratz said...

truly amazing how hard it can be to kill a plant that you want to die. I do believe my neighbor has one of these that stretches out to my pruners several times a year.

Town Mouse said...

What really amazes me is that these highly invasive plants are still available at regular nurseries. Shouldn't they at least come with a warning label?

Teresa said...

This is a very interesting post! Thanks for sharing.

When we moved into our house in California, the front yard had been taken over by English ivy. It was up to my waist, and you can just imagine all the critters living there.

It took us a year of hard work to regain our front yard and grow a normal garden. What a nightmare...

Kylee Baumle said...

Wayne ~ Isn't that the truth? Ha...stretches out to your pruners. Love it!

Town Mouse ~ That would be a great idea. I do believe some tags use terminology that might indicate the plant could be a problem, but don't come right out and say they're invasive.

Teresa ~ Oh my gosh! Nightmare indeed! I know English Ivy can be a real problem.

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