Tuesday, June 8, 2010

Invasive And Aggressive Plants Are Not The Same

When I first came to Astolat, twenty-plus years ago, I was enchanted with the pretty white flowers that filled the old orchard with blooms and delicate scent in late spring. HH called them 'sticker bushes' and I soon learned that the thorns of these shrubs give them a nasty bite. The shrub is, of course, Multiflora Rose (Rosa Multiflora), a very invasive plant.

We have white and pink ones.


How can something so delectable be so objectionable?
When HH decided to clean out the overgrown orchard and make it into our Woodland Walk, he had a mammoth task ahead. The multiflora rose is not the only invasive plant in there: Russian Olive (Elaeagnus angustifolia), Japanese Barberry (Berberis thunbergii), and Bush Honeysuckle (Lonicera Maackii) also abound. He pulled them out and cut them back ... to say it was hard work is an understatement. It was impossible to eliminate all of them, but they are somewhat under control. He created pathways. A bridge and arbor lead you there. 

We allow the Multiflora rose to cover the arbor at the entrance.

Invasive and aggressive plants are not the same. Aggressive plants, like mint and dandelions, are very fast growing and spreading, but they do not have the ability to compete with and outgrow surrounding plants as invasives do. One of the worst invasive plants is Purple Loosestrife (Lythrum Salicaria) which is so invasive its rampant growth threatens wildlife and wetlands throughout the country. It chokes out native plants that are integral parts of natural ecosystems. Thank goodness it does not grow on our land! The ones we have are bad enough.

Barberry is prevalent throughout the Woodland Walk.
(photo by Fine Gardening magazine)
Bush Honeysuckle and Russian Olive grow side by side in the Woodland garden.
 Russian Olive blossoms

Bush Honeysuckle

Plants that are considered invasive in one area may not pose a threat in another region of the country. Gardeners need to research what plants pose a problem in their region and avoid buying and growing them. An article in Fine Gardening magazine gives a useful list of plants to avoid. Click here to read the article. The U.S. Arboretum website provides very useful information, also.  If you have any questions you can speak with experts at nature preserves, botanical gardens, and extension services.
I must stress that none of the invasive plants in our woodland garden were planted by us! We are great advocates of native plants.

Your friend in gardening,
Pam x

PS Ruth at Muscari Musings has written an excellent post on Rose Rosette Disease. Click here to read what she says.

~~ I love reading your comments. I hope you leave one so I’ll know you visited!
I look forward to visiting your blog in return.

27 comments:

Jo said...

If you've got to have invasive plants on your land then it's good that they're so pretty. I also try to grow native plants in my garden, they're so much better for the wildlife too.

Cyndy said...

Good explanation of invasive v.aggressive. I like that you've learned to live with what is there, as it is so pretty!

gippslandgardener said...

Hi Pam, I can relate to the battle of invasives that are never quite 'all the way gone' Blackberry is my bane. As you say, these plants can be no problem at all in other parts of the country/world, but blackberry is a big environmental problem here. I guess it is not a coincidence that your rosa and my blackberry are related though!

Ruth said...

Hi, Pam, Not only are the MultiFlora Roses invasive, but around here, they are spreading Rose Rosette Disease. Last year, I had to destroy 4 of the (non-multiflora) roses I had planted and I am fearful of what this year will bring for my other roses. I think multifuloras are pretty in bloom, but now they just make me sad. I dread loosing more roses.

Thanks for your post! :)

Diane said...

Pam, it's really interesting that you posted this today, because just this very morning, for the first time ever, I pulled a plant out of my garden.

I'm not sure if it would be the invasive or aggressive variety, but it was growing (sneakily by underground roots) and getting into my other plants.

This plant is called a anaphalis or 'pearl everlasting'. It was one of the few plants left on our property when we moved here.

I felt kind of bad pulling it out, but I'm glad I did. I can see that the roots are going to need a little more attention from me before they are all gone.

Anyway this post was timely for me and very interesting!

Cheers.

pamsenglishgarden said...

Jo - You are so right about native plants being better for wildlife. The invasives don't provide the food the native wildlife need.

Cyndy - Thanks for visiting. I stopped over at your blog, Gardening Asylum (love the title), and enjoyed it very much!

Gippsy - It's very interesting that your problem plant is related to my problem plant!

Ruth - Thanks for the information about Rose Rosette Disease. I'll look out for it. It's very sad. I hope you don't lose any more roses.

Diane - I often find that the topics on other people's posts coincide with something I'm thinking about, or doing, at the time I read them. Amazing ... and fun!

Thanks everyone for visiting!

Noelle said...

Hello Pam,

This is an excellent post! I love how you explained the difference and that aggressive plants to have a place in the garden.

Corner Gardener Sue said...

Hi Pam,
I have been wondering what makes a plant considered invasive as opposed to just aggressive. I have some things I call, "spready" in pots. My octopus bellflower is probably consisdered aggressive, but it would take over the whole bed and grow right in, under, and over other plants. I am still pulling it out of an area I decided I didn't want it in, and am keeping it in check where I am letting it grow.

I was disappointed when purple loosestrife became illegal to grow here in Nebraska. I had some in a bed at church, and it wasn't even aggressive, but I was told the seeds get into the waterways. I even offered to keep it deadheaded, but they said to dig it out.

Another subject I want to learn more about is the difference between native plants and wildflowers. I'm thinking not all natives are wildflower, and not all wildflowers one can grow are native to their areas. Did I get that right?

Thanks for your nice comment on my blog. I love what you said about an aptly place watering can covering over a multitude of sins/bare spots. ;o)

Andrea said...

Hi Pam, my first visit to your new house! Somehow i thought grasses or most plants die during winter, which i found is not correct. We have more invasives and aggressives in the tropics because they can continue growing rain or shine, no winter to threaten them. They also remain good even during long dry seasons, they are really pests in the farms.

Meredith said...

Pam, what a great post. I often think about the difference between invasive and aggressive as having to do with how the plants spread. To me a plant is invasive if it escapes a person's yard and spreads to his/her neighbor's yard, or to the park down the street, or to creeks, etc. And while it might not be that person's plant that was the culprit, when you see "rogue" plants in a wildlife area or park and they shouldn't be there, those are invasive plants. Aggressive ones mean that you have to get them out of your other flowers' spots, but they are controllable.

Good work getting through all that work!

Dee @ Red Dirt Ramblings said...

Great post Pam. Here, we have the stupid Japanese honeysuckle and may have the multiflora rose, but I removed it long ago. The rosette disease is awful, and I feel tremendous sympathy for anyone who has it in their garden.

I own quite a few aggressives, but not so many invasives.~~Dee

Curbstone Valley Farm said...

Hi Pam, I'm also a transplant from England!

Great post! It is important to understand the difference between invasive and aggressive. Here, our invasive plants are things like Scotch and French broom, Vinca major, and Pampas grass. I grew up with Scotch broom! But here I understand the damage it does. We have some aggressive weeds too, that require diligence to keep in check, but the invasives, if we don't keep them in check, quickly smother our native plants.

I think as gardeners it's our responsibility to be aware of plants that are likely to escape cultivation in our respective regions, and encourage our garden centers NOT to sell them.

Town Mouse said...

Thanks for that post, Pam. This really is worth repeating. I admire you for making room for other plants and hope things you like will grow just as aggressively as some of the nasties.

Avis said...

Pam,
It's great to see your garden in spring. It's lovely. I really like your arbor. Can't wait to see more... Cheers!

country rose corner said...

What a lovely woodland walk! I have quite a few aggressive hardy geraniums especially mourning widow, and I must have pulled up 100+ large plants this spring in England.Serves me right for not deadheading last year! Best wishes from Kent, Betty x

Christine B. said...

Too true about what is invasive in one area is a lamb in another. I can't keep barberry alive (should I be ashamed of that?) to save my life.

Christine in Alaska

jodi (bloomingwriter) said...

What an excellent explanation of the difference between invasive and aggressive plants, Pam! Should be very helpful to many people.
I never know what to think about R. multiflora; the bees and birds seem to adore it, so for that reason it's a good thing. It's also used as the rootstock for many grafted roses, which is yet another reason why it has spread far and wide (while the more choice roses that were grafted withered and died, of course!)
The bane of my existence is goutweed/bishopsweed, which is just about the worst plant in the world next to purple loosestrife. I keep encouraging other people to boycott garden centres that sell it, or at the very least to NOT let it flower and set seed. It's a terrible plant. I don't think it's a wellbehaved one anywhere in the world, to be honest.

Rosey said...

Good information, Pam! I think I might have some nasty stuff around here that I need to pull out. I am still fighting those daisies. Argh.

teresa said...

That was very interesting. I hadn't really thought about the difference. Whenever I find a plant taking over, I try to get rid of it completely because they are sneaky little devils. It's nice to see you are able to use it's beauty on your arbor, sort of the old saying if you can't beat em, join em. I am always amazed when I see certain plants being sold in the nurseries and I know they are invasive in some areas. By the way your gardens look lovely, invasive or not you seem to have tamed them well.
ps. I changed your address on my blogroll. thanks for the heads up on that.

teresa said...

That was very interesting. I hadn't really thought about the difference. Whenever I find a plant taking over, I try to get rid of it completely because they are sneaky little devils. It's nice to see you are able to use it's beauty on your arbor, sort of the old saying if you can't beat em, join em. I am always amazed when I see certain plants being sold in the nurseries and I know they are invasive in some areas. By the way your gardens look lovely, invasive or not you seem to have tamed them well.
ps. I changed your address on my blogroll. thanks for the heads up on that.

teresa said...

That was very interesting. I hadn't really thought about the difference. Whenever I find a plant taking over, I try to get rid of it completely because they are sneaky little devils. It's nice to see you are able to use it's beauty on your arbor, sort of the old saying if you can't beat em, join em. I am always amazed when I see certain plants being sold in the nurseries and I know they are invasive in some areas. By the way your gardens look lovely, invasive or not you seem to have tamed them well.
ps. I changed your address on my blogroll. thanks for the heads up on that.

Autumn Belle said...

Invasive or aggressive, I enjoyed the flowers you have here. They are indeed lovely.

Carol said...

Great Post Pam! I feel for your hubby having to deal with all those thorny invasive plants. I have to do the same with many of those plus Bishop's Weed. The Russian Olive is very bad... it is said that you should not let it go to seed for the birds will spread it. I like aggressive plants and need them to survive the sea of Bishop's Weed but you are right invasive is quite different. Your arbor is so lovely!! ;>)

Edith Hope said...

Dear Pam, What a happy accident has brought me to your weblog.

I find the idea fascinating that you are attempting to combine the best of a quintessential English country garden into a wonderful American landscape.

This posting has much sound advice. Oh if only one had been warned about so many things when one started gardening, since, as you say, dealing with invasive plants can be very tricky indeed once they get a hold.

Whatever, the glimpses I have had of your garden show me that you have created a wonderfully romantic and beautiful spot.

Zoe Tilley Poster said...

I like your invasives/aggressives explanation - much more articulate (and accurate) than my "one man's weed is another man's wildflower" philosophy! Has the pygmy goat been any help with multiflora destruction? Will enjoy reading your blog! - Zoe @ pearled earth

Mad about Garden said...

Very interesting & eye opening post about the difference between the two varities invasive or not.

Thanks Pam for stopping at my blog.
BTW that picture you saw is Corn plant trying to dig more roots into the ground ,

Keep it a secret please :)

All the best.

pamsenglishgarden said...

Some very thought-provoking comments! Sorry I didn't respond to all individually. I will visit your blog soon. Thanks to everyone! P. x