Potentilla dilemma

23 posts / 0 new
Last post
Title: Guest


    I am really surprised that someone of your vast experience would know so little about invasive species issues.  I will try to address your statements point by point.

*"blaming horticulture for weeds is like blaming kids who shoot cap guns for Mexican gang warfare"

The fact is, the horticultural industry has introduced many species that have invaded undisturbed natural areas and require control efforts.  I will list some below.

Common Buckthorn - Now the most numerous plant in the Chicago Region.  No habitat has escape invasion by this species.  It was brought here for hedges.
Burning Bush
Japanese and European Barberry
Autumn Olive
Asian Bush Honeysuckles
European Cranberry Viburnum
Oriental Bittersweet

For a more comprehensive list please view the following link.


*"So called "invasives" are just weeds, and they are due to massive disturbance by farming, mining, urban and suburban development."

Many invasive species have completely dominated undisturbed natural areas.  Unlike native disturbance adapted species, invasive species are not out competed by more conservative native species over time.  Invasive species cause damage to ecosystems that is difficult, if not impossible, to mitigate.  They also have cause significant economic problems.  For example, Common Buckthorn is the winter host for an introduced insect pest of soy bean.  This raises food costs for everyone.

Giving the audience, I will also mention that I have observed nonnative species dominating the extremely limited (a few dozen acres at most) alpine areas in New York State.  Specifically, on the ridge as one hikes to the summit of Whiteface Mountain.  Having a future opportunity to grow cherished alpine plants will likely be dependent on preventing the introduction of species which can take over their wild habitats.

*"Horticulture is the solution to weeds, not the cause."

Regarding mitigation efforts for invasive species, I do not believe any effort has yet successfully eliminated an invasive plant from a continent.  In natural areas we can locally eliminate invasive species, but we must then continually monitor for new infestation from surrounding properties.

Also, horticulture cannot save a plant forever if we have altered its home to the point that it can no longer survive.  

*"The proof is that they have taken on innocent gardeners rather than those really causing the problem."

The fact is, many of the invasive plants I have listed continue to be sold by nurseries.  Natural area managers must be ever vigilant for new infestations from seed that is often spread from a neighboring landowner's garden.

"the relationship is tenuous in the extreme"

I understand that people want to be free to grow or sell any plant they desire.  It just is not fair for everyone to pay a steep price for the damage that is caused when an agricultural or garden plant escapes and takes over everything.  This is the reason I think all gardeners should only grow plants that are not invasive in their area.  It's just the responsible thing to do.



Tim Ingram
Title: Member
Joined: 2011-04-27

We had a similar debate on the AGS website about the use of peat in horticulture. Such discussion seems very quickly to polarise even though presumably we all have similar interests in plants and environmental conservation. Societies like the NARGS and AGS, with many thoughtful and educated (in the broadest sense) members, can only benefit such debate, even if it does get heated at times. The more people who develop a stronger understanding of plants the better, which is is why such specialist societies are so important.

Here in the UK we are probably fortunate in the relatively few plants that have become a menace despite the vast number of species grown. Plants do (usually) have quite specific ecological requirements, so each case needs to be taken on it own merits. Gardening does seem a more benign activity than many of the other more foolish things we get up to!

Dr. Timothy John Ingram
Faversham, Kent, UK
I garden in a relatively hot and dry region (for the UK!), with an annual rainfall of around 25", winter lows of -10°C and summer highs of 30°C.

Title: Guest


    Actually gardeners have played an intricate role in helping our parks and native species.  Each weekend volunteers meet and work in the Chicago region's preserves.


    It is an excellent community that loves to talk about plants, birds, and all other aspect of local natural history.  Some people have become so involved that they become Stewards who lead the efforts of volunteers at their site.  This program makes all the difference for these parks.
    Here is a link to one of the most involved groups.


    One activity that is not mentioned in the FPDCC link is seed gardening.  Home gardeners take local ecotype seed and grow plants at home.  They then collect seed from their home gardens for use in restoring natural communities.  Many plants in our parks have been significantly impacted by an exploding deer population.  Often, plants grown and protected by home gardeners are the only source for species that have been decimated by deer or over taken by invasive species.



Kelaidis's picture
Title: Member
Joined: 2010-02-03

I give up, James! You have a great deal more energy than I have. And Tim is right: we really do agree 99.999%. But I am cussed and stubborn too!

I don't deny that we do have culpability as horticuturists, and that there are serious issues impinging upon us...I also agree with your flattering remark about my "vast experience": I'll share just a smattering of that experience with you...

For approximately 17 years that I have lived in my current house I have been dumping the seed leavings from my pretty extensive seed collecting (I often gather up to 1000 kinds of seed from the wild, from my own garden, from friends gardens) on to the empty fields around my house. Now, don't panic! I am almost exactly in the middle of the Denver/Aurora metroplex (almost 4 million people) and despite that the five or so acres of more or less derelict and severely abused prairie around my house is totally isolated from "nature" so that if any of the seed I scattered there became established and weedy, I would not be polluting the great out of doors. [if indeed any of the seed I scattered did in fact become a potential pest, I would certainly clean them up pronto, believe me!] But I hasten to point out that in 17 years of scattering these leavings (which I would not doubt come to millions if not billions or perhaps even trillions of seed) I have had only a handful even germinate to the extent that I have noticed them in these said fields. And none of these has persisted. It apparently takes a lot to become established as a weed here. Albeit that in my own garden I manage to grow rhododendrons, azaleas, hundreds of cacti, thousands of alpine plants and plants as diverse as Lithops, Meconopsis, Aloes, Eritrichium, Sarracenia and Nerine on the godforsaken plains of Colorado.

Although we do have an abundance of weeds, practically all of which came with the Red Durum wheats brought by the 19th Century immigrants from the Volga when the dryland farming was established on the Great Plains. No wheat to weeds. No weeds, no wheat: that paradox (that we continually generate the problems concomintant on our survival) a paradox that Western Science and environmentalism just don't get. But we latter day Taoists grok immediately.

The most "notorious": of our local horticultural invaders are Russian Olive and Tamarisk (which I must admit, I have a grudging admiration for). I am not so perverse as to plant these, although I believe the reaction against them is overblown and misdirected. The riparian areas that these "horrible invasives" have colonized are really new ecosystems humans have created by damming innumerable streams (if you fly over the Great Plains of Colorado you will see hundreds, if not thousands , of impoundments..ie.e. lakes and ponds. NONE of these existed in pressettlement times.  Countless millions of dollars have been spent to eliminate these "menaces" only to discover that they have become superb bird habitat, and that an endangered native bird (Southwestern Flycatcher) is dependent on theim for its survival. Get rid of the Eucalypts in Southern California and bye bye Monarch butterflies. Nature works in strange ways. In the pre-human days these "invaders" would have long ago been scraped away by our frequent and devastating floods we have obviated (who is mourning for those floods, by the way? as natural and wonderful as any thing in Nature: obliterated by the hand of man as surely as we sow weeds). It would take a REAL environmentalist to take a stand for those floods. I don't see anyone raising their hand!

Your concern for horitcultural impact on the landscape, Jim, is valid. I am distressed that you do not acknowledge that the REAL impact on our landscapes are due to other land abuses which CREATE the habitats for weeds . It is a question of emphasis and scale. I aver that our impact is really trivial in the big picture, and it is the big picture that concerns me. 
And I am especially concerned that this imbalance of emphasis is causing people to be turned off of horticulture on the one hand (which is the most powerful link the average person has to connect with nature now that over half humanity is urbanized) and therefore becoming "desensitized" to the problem all the mre. That is a subtle argument, perhaps, but one I believe has merit.

I end by saying that the Tallgrass prairie (and Oak glades) is indeed the greatest ecological tragedy that humanity has inflicted on almost any ecosystem I am aware of, and the work that has been done by Midwesterners to restore these prairies wherever possible and raise awareness about them is one of the great success stories of both Horticulture and environmentalism. I do honor your commitment to preserving and protecting your regional ecosystems with your genuine and fierce and admirable passion! I salute you from the bottom of my heart and from the depths of my soul! (And hope one day you will forgive me for being an unrepentent gardener who perhaps loves many weeds just a tad too much).

For every minion of the peaks there are a dozen steppe children growing in the dry Continental heart of all hemispheres still unknown to horticulture.

Title: Guest

"I am distressed that you do not acknowledge that the REAL impact on our landscapes are due to other land abuses which CREATE the habitats for weeds."

I can only address so many issues at one time.  The fact is, once the ecosystems in my area have been destroyed, current knowledge indicates they will not recover completely.  This is the conclusion of researchers that have studied restoration efforts which have been continuously occurring for 50 years or longer.  Even the oldest prairie reconstruction attempts do not have the Floristic Quality Index values, the remnant dependent insects, or the microbial communities that are necessary components of the ecosystem.  This is the case even when the restoration efforts are occurring adjacent to a remnant.  Researchers have stated that sere ecosystems are succeeding towards an alternate stable state.  Although my personal observations are somewhat at odds with these results, I can say that most prairie species spread very slowly without assistance.

The irreplaceability, along with the rarity, of our local remnants makes any further loss unacceptable.  Illinois only has one tenth of one percent of its original landscape remaining.  Many of these remaining ecosystems are isolated refuges of less than 20 acres.  Most people in Illinois grow up without ever seeing an example of the presettlement vegetation.

I write the above to make people understand the importance of protecting intact ecosystems, not to discourage those who might attempt to restore areas that have been degraded.  Restoration of areas destroyed by farming or gravel mining have had great successes.  We have been able to establish nearly every plant species.  Unfortunately, we rarely achieve the abundance or quality of plant communities found in remnant ecosystems.  Also, restorations are not as ecologically resilient.  They often lose diversity over time.

I hope my writing informs people of the importance of protecting natural areas.  Let the experiences of my region be a lesson.  Do not let what happened in the Corn Belt occur where you live.

"Although we do have an abundance of weeds, practically all of which came with the Red Durum wheats brought by the 19th Century immigrants …"

It is important to differentiate between weeds and invasive species.  Local conservationists define invasive species as either introduced or native species that spread in a malignant manner.  Examples of native species that are locally considered invasive are disturbance adapted woody species that invade prairie, savannah, and oak-hickory woodlands.  Often this invasion is due to the lack of regular fire.  The USDA defines invasive species as “a species not native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.”

After more thoroughly reviewing the Chicago Botanical Gardens list of invasive species, I must admit it is too extensive.


A number of species they list as invasive do not invade natural remnant and have been shown to be outcompeted by native species in restorations.

“The most "notorious": of our local horticultural invaders are Russian Olive and Tamarisk (which I must admit, I have a grudging admiration for). …”

I am unfamiliar with your local ecosystems and therefore cannot comment on the invasiveness of the species for those areas.  However, I have heard these same remarks before.  It seems to me that people of various motivations use any small ecosystem service provided by non-native species as reason to do nothing.  I think conservationist put it best when they say, “Now I have a citation for giving up.”  I cannot stop you if you prefer to make excuses rather than face the problem.  All I can do is put my efforts toward mitigating the damage these invasive species have caused.   

“(And hope one day you will forgive me for being an unrepentent gardener who perhaps loves many weeds just a tad too much).”

I love species that are invasive too.  I just wish they had not become establish (usually with our assistance) into my local ecosystems.  Every invasive species came from someplace.  Personally, I would be happy to admire these species in their native habitat.



Kelaidis's picture
Title: Member
Joined: 2010-02-03

Dear James,
    I have enjoyed our exchanges a great deal: we are not so very far apart! I sometimes think the sort of heated discussions we have had must be the contemporary equivalent of those medieval arguments over how many angels fit on pin head.

    We both yearn for landscapes that are not cluttered with the effluvia of human indifference and ignorance. And that we as humans treat the landscape with sensitivity and respect. I don't know a gardener or conservationist who does not share those commitments, although the way we phrase them or our emphases may vary.


For every minion of the peaks there are a dozen steppe children growing in the dry Continental heart of all hemispheres still unknown to horticulture.

cohan's picture
Title: Guest
Joined: 2011-02-03

I haven't had a chance to visit here for a while- so it was interesting to see the posting in this thread! I think I discarded (while working on general rebuilding of a 30 year overgrown rock garden) a couple of those Potentilla plants (which I'm pretty sure are P recta) but they are probably not all gone, and certainly more will come up from seed..
I'm still a bit torn about the plant-- I really do love the flowers, which are a colour unlike any of the natives, and I don't think the reports of invasiveness are from Alberta so far, rather from B.C. It seems to me its drier areas where it has been problematic (some comfort that Panayotis has not had any problems with it) and my zone just outside the foothills biome is one of the moister parts of the province outside the mountains. Also, the plants did not spread at all from my  original planting 30 years ago- the plant had died out and regrew from seeds only after I'd started re-digging...
Still not fully decided, may just stick to the native P gracilis- a more standard yellow flower, but nicer foliage!
Likely I should be more worried about large patches of tall Veronica  Geranium himalayense  and (smaller patches) Campanula rapunculoides planted by my mother!
Then what about a couple of clones of Geum--sorry Potentilla -- nepalensis I have planted- the one plant established a couple of years likely made hundreds if not thousands of seeds this year- should I be worried?
I don't care about plants that make themselves a nuisance in the garden, but my property is surrounded by semi/natural land (its all farmland around here, but much is only grazed, and there are many native species) and I worry about escapes (none so far).
In this region almost all the weeds and invasives are related to agriculture (all of the ones I know of, at least outside of towns/cities)- almost all of them come directly from agriculture (as weeds or escaped forage crops) and all are spread by agriculture- cultivation and or grazing/overgrazing.
I too have thought longingly of living someplace with a 'pure' (or nearly) flora, unpolluted by agriculture.. Whitehorse, Yukon seems like kind of a cool small city  ;D

west central alberta, canada; just under 1000m; record temps:min -45C/-49F;max 34C/93F; http://picasaweb.google.ca/cactuscactus  http://urbanehillbillycanada.blogspot.com/

Lori S.
Title: Moderator
Joined: 2009-10-27

With the exception of Campanula rapunculoides, none of the plants you mention is invasive* or been recorded as naturalizing.  You can always check Noxious Weed and Prohibited plant lists for Alberta and for various cities, and USDA Plants to check on this.

*I find that Geranium himalayense spreads itself around a bit but not on the scale of things I'd call "invasive".

Calgary, Alberta, Canada - Zone 3
-30 C to +30 C (rarely!); elevation ~1130m; annual precipitation ~40 cm

cohan's picture
Title: Guest
Joined: 2011-02-03

I feel quite sure the Geranium would take over the entire acreage give the chance..lol Its in several patches of several square metres and spreads beyond them into mowed areas, and I think seeds into the mowed area (really can't call it lawn- grasses, native plants, weeds like plantain, dandelion and clover).. worst thing is, I really don't like that electric purple colour :( why couldn't it be pink or white or even violet??
The thing to me that is scary about invasives is that there is little way to know until it happens-- wasn't purple loosestrife grown as an ornamental in North America for quite some time before it became invasive?
I think at least several of the spp I mentioned above have probably been grown for quite some time in farm gardens around here, and they are not evident in 'natural' areas, so you'r probably right they are not a big threat- I think I've seen the Campanula in exactly one place outside a garden near here, and it was very near a farm yard... Still, I'm not very fond of any of those, and wouldn't mind getting rid of them, or at least gradually reducing them! I've started removing spent flowering stems from the Veronica- they seem to seed quite far from the plants (at least several/maybe 10 metres)-including uncultivated soil..
There's also a large Clematis tangutica on the corner of my mom's house, but I have never seen a seedling in spite of what seems like 20-30 pounds of seed annually!

west central alberta, canada; just under 1000m; record temps:min -45C/-49F;max 34C/93F; http://picasaweb.google.ca/cactuscactus  http://urbanehillbillycanada.blogspot.com/

cohan's picture
Title: Guest
Joined: 2011-02-03

Just because I happend across some pics while looking for some other things, here are some of the things discussed above..
1 Potentilla nepalensis, labelled Miss Willmott, not sure if that is right- google images shows various colours under that name, I really like this orangey flower; I now also have one labelled, I think, Ron Mcbeath (sp?) with deep pink flowers;
2-6 Then what I believe to be Potentilla gracilis, growing just outside my driveway



The rather aggressive Veronica, and a couple views of Geranium himalayense

west central alberta, canada; just under 1000m; record temps:min -45C/-49F;max 34C/93F; http://picasaweb.google.ca/cactuscactus  http://urbanehillbillycanada.blogspot.com/


Log in or register to post comments