Native Cultivars – Good, Bad, and Ugly

Native plant cultivars are a vexing topic.  My experience has been that gardeners who are increasing their use of native plants are likely to find the topic of native plant cultivars to be confusing, and for good reason.  There is a tremendous amount of variation in the traits for which cultivars are maintained, how the cultivars originated,  and in how cultivars are propagated.

Echinacea ‘Coconut Lime’ cultivar, image copyright William Cullina

Most people take the term “cultivar” to be a contracted version of the phrase “cultivated variety”, a phrase which carries with it the structure of a most basic definition.

Cultivars are plants which are selected and/or bred by humans based on one or more specific traits, and which are then propagated in such a way that those traits are maintained. In other words, cultivars differ from “typical” examples of the plant species to which they belong AND that difference is important enough to somebody that the person is willing to expend time and energy to preserve the difference.  Cultivars are often maintained because they have an unusual flower color, leaf color, growth habit, or disease resistance.

There are three different ways in which a cultivars can first arise.  The first, and oldest, method is selection, in which an individual plant (or population of plants) naturally exhibits an atypical appearance or behavior.  Someone notices, and propagates that plant in such a way that the atypicality is preserved.  The second method is hybridization, in which two different species or varieties of plants are bred and their offspring is propagated.  Some cultivars are naturally occurring hybrids, found in nature at the boundary between two closely related species, but many cultivars are created at nurseries by plant breeders.  The third method is genetic engineering, in which humans directly manipulate the DNA of plants to produce some desired trait. If we limit our attention to cultivars of native plants, we can ignore genetic engineering since it is restricted – because of expense – largely to medical, industrial, and agricultural applications.  Most cultivars of native ornamental plants are either selections or hybrids.

Ilex verticillata, image rights reserved wallyg

Finally, there are two basic ways that the valuable traits of a cultivar can be maintained:  the cultivar can be propagated through cloning or it can be grown from seed.  Most cultivars of native plants (about 70%) are genetic clones, which means that each plant has exactly the same DNA.  The clones are grown by cuttings, by division, or by tissue culture. Some cultivars will grow “true” to seed, which means that seedlings will have the same important trait as the parent.

Okay, that’s a lot of background:  why does any of it matter?

When you are trying to decide on a native plant for your garden, all of these details can potentially help you decide whether or not a cultivar is the “right” choice for you.

1. Cultivars look different. Almost by definition, cultivars do no look like “normal” or “typical” examples of a plant species.  If they did, there would be no need to mess with a cultivar.  Whether or not this matters to you is, well, up to you.  If you want to plant Ilex verticillata, or Winterberry holly, but the ten foot mature height is a problem then maybe the cultivar Red Sprite – at a mature height of four feet – is exactly what you want. On the other hand, if your goal is to accurately represent the native flora of your site then a dwarf cultivar may be suboptimal.

2. Cultivars have less genetic diversity. This is a tricky one, because there are no hard-and-fast rules:  even some plants that are NOT marketed as a cultivar are actually propagated clonally:  if you care about genetic diversity, you have to ask your grower whether the plant was grown from open-pollinated seed (and make sure your grower has a firm and nuanced understanding of what this means). Open-pollinated seed collected from remnant wild populations is the gold standard, but not common.  Genetic diversity is a valuable insurance policy, since a diverse population has an increased probability of resisting threats from disease and/or pests. Another wrinkle is plant gender.  In some cases, like our native inkberry (Ilex glabra), every single commercially available cultivar is female.  Without male plants around, there will be no fruit on these hollies.

 

 

 

 

Physocarpus opulifolius ‘Diablo’, image rights reserved dragontoller

 

 

 

3. Cultivars behave differently. Because cultivars have been selected primarily on ornamental traits, it is not always clear whether or not they perform the same ecological role as the native plant species.  In many cases they do not.  For example, Echinacea cultivars have become nearly a fad and some examples are quite bizarre in color or in flower shape.  These Echinacea cultivars are sometimes sterile (bad news for goldfinches, who want the seed) and often have a “doubled” flower form (bad news for pollinators, who can’t effectively reach the pollen and nectar).  Another example is Eastern ninebark (Physocarpus opulifolius), the most popular cultivars of which were selected for dark (i.e. purple) foliage instead of the normal green.  It turns out, the “improved disease resistance” of the dark-leaved cultivars like Diablo and Summer Wine results from the specialist native ninebark beetle (Calligrapha spiraeae) finding the cultivars to be an inferior host, since the leaf chemistry of the cultivars differs in important ways from the species. Another potential problem with native cultivars is fruit (e.g. berry) size:  many culitvars were selected for bigger and/or more fruit, which may be nice to look at but may also be inedible to wildlife.

So, what is a native plant gardener to do?

I have planted, and will probably continue to plant, cultivars of locally native plants.  However, my first choice will always be a locally-sourced open-pollinated seed-grown plant.  My second choice will be a cultivar that maintains the flower shape, berry size, and leaf color of the species. My goal is to never buy cultivars that exhibit radically different flower shape or color, but I will knowingly buy dwarf varieties which are otherwise similar to the species. And when I see a cultivar touted as resistant to insect damage, that one gets an automatic rejection.

I also pay extra attention to observing my cultivars in the garden:  if I don’t see pollinators on the flowers, or insect damage on the leaves, or birds eating the fruit then I am quite likely to rip out the cultivar and try the species.  This is my policy because my primary motivation for using natives in the first place is that I want to support my local ecology.  If I can’t see evidence that a cultivar is helping me accomplish that goal, I fire it and hire a plant that will.

 

© 2011 – 2014, Vincent Vizachero. All rights reserved. This article is the property of Native Plants and Wildlife Gardens. We have received many requests to reprint our work. Our policy is that you are free to use a short excerpt which must give proper credit to the author, and must include a link back to the original post on our site. Please use the contact form above if you have any questions.

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Comments

  1. says

    Great post Vincent. I have been meaning to investigate information about the Ninebark cultivars. I have the species Ninebark as well as a few Diablo near the street. I have debated on removing them for they are the only native cultivar in my yard, and to me they look so out of place. The foliage colors in the landscape trade are so obnoxious, the bright golds, wines and lime greens. I think there’s much to appreciate in the simplicity of our native plants and the subtle differences in open-pollinated seed grown plants. One of my favorite growers collects seed within a 50 radius of his nursery.
    Heather
    Heather recently posted..Robber Flies- Wolves in Sheeps Clothing

    • says

      Thanks for the compliment, Heather. This topic is a big one, and I hope I at least achieved coherency!

      The ninebarks were a tough example, since the purple-leaved cultivars have all but completely replaced the (more normal) green-leaved varieties in the commercial trade. I suppose I would prefer that someone plant a native cultivar than a non-native, but I would prefer that people have choices even more.

      I also get sad every time I see a purple-leaved Eastern redbud.

  2. says

    Those newer coneflower cultivars are crap all the way around, living out their short lives like the first drafts of a Frakenstein man. There are plenty of species cones with enough variety to satiate folks–unless they do really like that fluffy mounded quadruple petal junk. I have a ‘Coppertina’ ninebark, and pollinators love it. Not much leaf damage, though. I’m for letting cultivars revert back to species (that IS how it works, right?), and let them do their thing. I think, though, we won’t see any change in consumer buying habits towards native species, because there aren’t any in nurseries. When’s the last time you saw an ozark or reflexed coneflower for sale in person? Native elderberry?
    Benjamin Vogt recently posted..Tour My Garden – Pics &amp Video

  3. says

    Helpful information. A question about seedlings that sometimes self sow around these cultivars(although I have noticed many are sterile or nearly so), are they reverting back to the species when you see the leaf color and size or blossom are back to normal?

    • says

      I’ll throw out the caveat again about there being no hard-and-fast rules, but basically I would answer “yes, possibly”. If the cultivar has been propagated vegetatively, then the chances are good that the seed-grown offspring will perform their ecological function better than the cultivar itself did. I wouldn’t go so far as saying they will go “back to normal”, necessarily, if only because you will probably still have a severely inbred population unless you have a genetically diverse population nearby as part of the breeding pool.

  4. says

    Benjamin, you’re highlighting the issue with natives for me – they’re not available! I design them in for a client’s landscape, and I can’t fricking find the plant that’s growing along the side of the roads! Irony, hey? But I can find the purples, the rufflies, the funny colors. And I love that stuff, but I’d also like to be able to plant the normal one, too, particularly, as Vincent points out, when there is compelling reason to prefer the usual one, which is often. It’s a shame.

    Vincent, great article, you answered a number of questions for me and clarified a great many points.
    Genevieve recently posted..Deer-Resistant Plantings You Can’t F Up

  5. says

    What a wonderful article!

    My personal experience:

    I purchased the wildflower gaura at a master gardener plant sale. Then I found some naturally occuring on my rural property. What a big difference in the look and in the usage by native insects. The naturally occuring wins hands down in the benefit to wildlife, although I’m sure there are gardeners who would opt for the one cultivated to produce more prominent blooms.

    I find it sad that some choose their own needs over the needs of mother nature. Glad to see you bring to the forefront the importance of paying attention to what best benefits wildlife and rethinking what we plant if it doesn’t measure up.
    Loret T. Setters recently posted..The Blur of the Butterfly – Missed Opportunity

  6. Suzanne says

    This article should be titled, “When a Native isn’t a Native”. I appreciate the clear explanation regarding “What’s a cultivar” but wonder if a cultivar of a native can be considered a native plant, truly. I mean, where does the definition of native end and cultivar begin? Does cultivar equal native simply because it originates from a native plant? The three ways in which a native is “cultivared” so clearly explained is very much appreciated. And, observation of the garden as a clear definer of a healthy ecology, top notch. Thank you.

  7. says

    Great piece, Vincent. Toooooooooooo many people never give it a thought and wonder why their recently purchased garden gems aren’t drawing in insects. So much education to do! Thanks for covering this important topic so well! Love your ending. I too have no patience for plants just taking up space.
    Pat Sutton recently posted..2011 Wildlife Garden TOURS

  8. says

    One case in which cultivars are not only justified but a necessity is when the native species is going extinct because of an introduced invasive pest. I am all for creating cultivars of elms, American chestnuts and hemlocks. That is probably the only way to save them from Dutch elm disease, chestnut blight and hemlock woolly adelgid. How long will that take? Sigh!

    • says

      That’s a great point, Beatriz! I have been using Princeton and Valley Forge elms quite happily, and cannot WAIT for the day we have commercially available blight-resistant chestnuts. Literally, I can’t wait: I’m growing non-resistant American chestnuts as a host plant, knowing full well they will one day succumb to the disease.
      Vincent Vizachero recently posted..Want to Avoid Nativars? Look Here.

  9. says

    Great article, Vincent! This is a discussion that needs to go much further. Thank you so much for beginning it with such clarity. One trouble with cultivars is that when you change the appearance to the extent of creating extra petals often native pollinators are unable to reach the nectar, and also because the plant is putting so much extra energy into those double and triple flowers, the nectar is no longer a high quality source.
    Carole Sevilla Brown recently posted..Do Black Swallowtail Catepillars Lay Their Eggs on Dill

  10. Carole says

    I have a cultivar of lyre-leaf sage. I wonder what will happen when a pollinator distributes pollen from the cultivar to the natives and they produce seed. Will I have affected the native plants with my purchase?

    • says

      Carole, I wouldn’t worry much about your cultivar polluting the gene pool of Salvia lyrata. I’m guessing your cultivar is a purple-leaved variety, and if so it likely grows “true” from seed. This typically indicates that the cultivar is genetically stable, and many sources would consider it a variety (aka “sub-species”) as opposed to a much less desirable hybrid. While a more normal looking plant would probably have better wildlife value, it is quite unlikely your cultivar will do any harm to existing natural populations.
      Vincent Vizachero recently posted..Why is Anise-scented Goldenrod so rare?

      • says

        I think I may have read this before, but came across it again, doing a search, after reading about a cultivar found in nature, and am trying to get unconfused.

        I am not one who has many true native plants that originally grew in our area. I do have a good number of plants native to the plains. Before I found some of the natives, like phlox pilosa, I found their cultivars and planted them. I now have sets of several growing, and don’t remember which are which for those that don’t look much different. It bothers me to think they will cross with each other, and if I share with others, they aren’t necessarily getting something native. Still, there is plenty for the pollinators, and I don’t see fewer on the cultivars so far.

        We live in the middle of a city, so I keep reminding myself that a true prairie will not be achieved here. Still, at this point, I am determined to fill any hoes with species somewhat native to our area. I am pleased with the number of pollinators that frequent the plants here.
        Corner Garden Sue recently posted..Looking Back to the First Couple Weeks Of June, 2013

  11. says

    Great succinct source of good info.

    “For example, Echinacea cultivars have become nearly a fad and some examples are quite bizarre in color or in flower shape.”

    I appreciate the beauty of some of these cultivars and hybrids for what they are – a beautiful flower, but for me they do not result in the same sense of wonder I experience when I see a native species in its native habitat (in my case a very tough habitat) displaying a surprising fragility or extravagant color.

    • says

      Renee,

      It’s important to note that cultivars of native species ARE native species to begin with. To use your example, “Howard McMinn” manzanita is a cultivar of Arctostaphylos densiflora, a species native to Calfiornia.

      To your question, the offspring of most cultivars will lack some or all of the characteristics for which they are cultivated. For example, it is likely the offspring of Arctostaphylos densiflora ‘Howard McMinn’ would be less compact than the McMinn cultivar would be.

      Hope this helps.
      Vincent Vizachero recently posted..NWF and Scotts: We’ve seen this story before

      • says

        Cultivars of native species are still native? HHHHm… I want to plant ilex vert. ‘Red Sprite’ but the town says Red Sprite is a cultivar and thus not native and not allowed (habitant restoration planting). For all I see, the cultivar is the same just dwarf. Is there literature that will help in my arguement?

        • says

          Sophath,

          Cultivars of native plants are, indeed, still native.

          But whether a particular plant is appropriate for a particular project involves a lot of variables.

          One aspect of cultivars that often concern people who draft lists and guidelines like the one it seems your town is using is that most cultivars have – by design – less genetic diversity than seed-grown plants.

          All specimens of “Red Sprite” are genetically identical, and this might not be ideal for a habitat restoration project. While I adore ‘Red Sprite’ as a good dwarf variety for residential and commercial landscapes, I can understand why it might be frowned upon for a true restoration project.

          On the other hand, if your town is applying restoration criteria to a managed landscape (e.g. in front of a courthouse or in a public park) then their objection is harder to fathom.

          Perhaps if your design included ‘Red Sprite’ only where the dwarf characteristic is absolutely critical and specified seed-grown plants for less accessible or visible areas the town might accept a compromise?

          • says

            Wow. Thanks for your reply!
            We want to maintain the view to the water – thus the shorter cultivar. We’re in the coastal buffer zone, so natives are required. I still think if the birds still eat the berries and find shelter in the shrub it is a valuable plant… anything is better than phragmites that has to be removed.

  12. Linda Porter says

    The chances are great that some commonly sold “natives” are cultivars regardless of where you buy them. Cultivars of garden phlox, bee balm, purple coneflowers, coreopsis and even solidago are sold so widely in nurseries and planted so extensively in gardens that it is difficult to know exactly what you are buying. Varieties such as Echinacea “Magnus” and Monarda “Cambridge Scarlet” are so close to the native in appearance that they would test the identification skills of all but the more skilled and informed professional landscaper. It is discouraging to buy what you think is a native only to find that it is attracting almost no pollinators.

  13. says

    Vincent, nice job on articulating in a tangible way, a topic that is so confusing to many gardeners. In our native plant collection, we limit our use of cultivars – and if we do use some, I always include some non-cultivars of the same taxon. Come visit us at Birmingham Botanical Gardens!

  14. Dee says

    I learned many new things from you today, thank you for an excellent & very educational article. I’ve noticed that many cultivars don’t bring the pollinators & birds to my garden. As I’ve learned more about native plants, I’ve realized that the more man tries to “improve” Mother Nature, it’s usually a dismal failure for the local wildfire I’m trying to bring in.
    I’ll be removing several cultivars in the spring. I was very disappointed they didn’t attract any pollinators.
    I’m very limited on space & I would like to plant the Holly Bush to feed the Robins & other birds during the long hard Chicago winters. Now that I’ve learned every bush available for sale is a female, I have no idea how to find a male bush, or how to tell the difference between them. I’m back to square one.

  15. eric peterson says

    Nativars suck the life out of everything I stand and srtrive for….keep local genetics were they are found people!!!..and have fun educating your wild yard to the neighbors!!! Its a movement that you must keep faith in. Push the boundaries where ever you live:)

  16. says

    I struggle to explain to folks that, when we – as humans – tamper with the process of *natural* selection, it isn’t natural any more. When we select out for certain traits – inevitably something to do with flower color or form, foliage color or overall form (smaller/larger/more columnar), we are affecting traits we don’t even “see” – nectar quality/access, markings outside human visual range but critical to insect interactions, etc. There’s a reason these plants are the way they have evolved – it works. Human beings have major control issues, coupled with a constrained desire for novelty (the newest version of the same 12 plants everyone plants), making it a challenge to “sell” the native plant concept to the average gardener. But I am seeing progress, despite setbacks such as a recent article in Horticulture Magazine. The journey continues….

    • says

      Cheryl, I think that if our goal is to take native plants “mainstream” then realities of what that involves must be confronted. And the truth is that native plants will never be widely used in designed landscapes if designers do not have a broad selection of native cultivars to choose from.

      A “local ecotype” is, after all, just another form of cultivar: a plant variety cultivated for specific traits, only in this case that trait is geographic provenance.
      Vincent Vizachero recently posted..New Post on the Downside to Biodiversity

  17. Ann says

    I find that the key is not being overly reliant on one cultivar. Cultivars are here to stay. We have short cousins and tall cousins; we don’t exclude them from the gathering. As a designer, small spaces are particularly challenging and the dwarf cultivars fill an important need. Similarly, clients will accept the more compact forms of a native when they would otherwise not accept a random form native. Good design requires meeting the social and aesthetic challenges while creating ecologically diverse and healthy solutions. I have seen our natives in European gardens doing very well. It’s not the plant, it’s how it’s used.

    • says

      I agree, Ann. If I use cultivars then I try – when I can – to use more than one, and include some straight species specimens on the site as well if conditions permit it.

      Also I think your point about acceptance is critical. Our designs need to be not just ecologically sustainable but also socially sustainable: we need buy-in broadly enough to keep the natives in place. In an urban or suburban environment, that means keeping this “neat enough” to prevent the whole thing being ripped out and replaced with a mulch garden and boxwood pimples.
      Vincent Vizachero recently posted..Waterkeeper & CBF Win OK for Extensive Study Of Waters Near Sparrows Point

Trackbacks

  1. [...] Sonoran Sunset Agastache brings in the hummingbirds to slurp it’s sweet nectar.   I am always a little concerned about purchasing one of these ‘cultivars’ as they are often cultivated for attractiveness to people not hummers and also for their lack of [...]

  2. [...] cultivars of plants that are in order to preserve the native ecosystem (read more about cultivars here); and I think that plants do best, including in how well they attract birds and butterflies native [...]

  3. [...] Vincent is a native plant advocate and environmental educator. His thoughtful approach to educating people about the value of native plants in our landscapes is refreshing. Read his post Native Cultivars: the Good, the Bad, and the Ugly [...]

  4. [...] We want to do the right thing and select plant material that can be a food source to wildlife, but we also like flowers that are brightly colored, bloom a long time, and fit into dependable size ranges (compact, tall etc.).  So, how far can we stray from the original species?  The answer is clear as mud.  Thanks to the research of Doug Tallamy we are beginning to understand the issue a bit better, and it has everything to do with leaf chemistry, shape, and toughness.  Without further research you can’t assume that a cultivar has the same palatability as the parent species.  A grad student at UVM is beginning to conduct research on the pallatability of Nativars, and I look forward to reading her results.  Until then, I follow the advice of Vincent Vizachero who wrote a good article about Nativars for the Blog Native Plants and Wildlife gardens: [...]

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