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Seed-Sown Plants and Genetic Variation: Aster Colors

October 2, 2020

Alma Potschke colorPlants can reproduce in two ways, sexually and asexually. In sexual reproduction, the pollen from one flower meets an ovule from a different flower and the result is a seed that mixes genes from both parents. Just as two children of the same parents will not have exactly the same mix of the parents’ genes (unless the children are identical twins), seeds differ genetically from one another. In asexual reproduction, by contrast, a living plant is cloned by taking root divisions, cuttings, or tissue cultures; and each plant produced in this way is genetically identical to the parent plant.

Many of the perennial plants available to gardeners through the nursery trade are named cultivars. Cultivars are either deliberately bred through a series of sexual crosses to get certain desired characteristics or they are selected from seedlings because they have distinctive desirable characteristics. Either way, the plant with the desirable characteristics is then cloned over and over again. If I include three plants of Echinacea purpurea ‘Magnus’ in my garden, those three plants are genetically identical to one another and to all other ‘Magnus’ plants sold in nurseries. Those making a living in the nursery trade prefer cultivars because they are predictable; you can tell a customer with confidence that the plant will mature to a predictable size and will have flowers of a predictable color. The trade-off for this predictability, though, is a loss of genetic diversity.

When I decided to add New England asters (Symphyotrichum novae-angliae) to my garden, I bought the only variety available at local nurseries, a cultivar named ‘Alma Potschke.’ ‘Alma Potschke’ was selected to be cloned because it has an unusual color, a bright reddish pink that is outside the usual purple-magenta-pink color range of the species (photo at top of page). When ‘Alma Potschke’ bloomed in my garden, I realized that I didn’t like its color as much as I like the colors of wild asters blooming along roadsides in Maine. The following year, inspired by Heather McCargo of the Maine Wild Seed Project, I collected seeds from a wild aster growing in my neighborhood. By the time I was ready to plant more asters in my new front garden, I had some seedlings grown from my collected seeds and additional seedlings purchased from Prairie Moon Nursery in Minnesota. Now those New England asters are blooming on my front slope, and I am thrilled with the genetic variations of color on my seed-grown asters.

NE Aster Color Variation

17 Comments leave one →
  1. Pat Webster permalink
    October 2, 2020 6:34 pm

    I’ve also started plants from seeds harvested in fields, ditches and along highway verges. I love seeing them bloom. Not only are they gorgeous themselves, they bring me a high degree of satisfaction — I’ve grown them myself and helped the plant survive

    • October 5, 2020 3:53 pm

      Pat, I agree; it’s very satisfying — at least it is when the seeds germinate and the seedlings thrive. I enjoy the adventure of the genetic surprises.

  2. krispeterson100 permalink
    October 2, 2020 9:50 pm

    That’s a beautiful range of color, Jean.

    • October 5, 2020 3:54 pm

      Kris, It was fun to try to capture the subtle color variations with my camera.

  3. October 3, 2020 7:48 am

    Your asters are lovely! I am interested you have such great bloom on your dry slope during this drought. I lost one aster and barely saved two others in June during part 1 of the drought. The survivors are alive but not blooming. It makes me guess that the natural habitat is moist well drained soil.

    • GARY permalink
      October 3, 2020 10:59 am

      My wild Asters are growing everywhere. Dry areas aren’t affected. Are yours wild?

      • Anonymous permalink
        October 3, 2020 7:03 pm

        Mine are not wild. They are clones. In checking cultural information, wild ones are usually in mesic soils, meaning moderate moisture. I asked Jean because I know her soil is dry and sandy. She lives not too far from me and has experienced a similar drought to mine. Wild asters in the wild have put themselves where they can best survive.

        • GARY permalink
          October 4, 2020 12:51 pm

          Thanks. Just checking because I live in Gorham, not too far from you guys and suffering from the drought too. The last 4 years I’m going full bore with The Wild Seed Project and the Audubon native plant sale. These droughts are becoming more frequent lately. I hope my Donald Wyman crabapple survives. A lot of apple trees are suffering according to UMaine.

    • October 5, 2020 3:57 pm

      Harriet, I have two hypotheses here (not mutually exclusive): First, these asters are growing in the middle of the slope, where I added quite a bit of manure and compost to change the structure of the soil and make it better at retaining moisture. (I also did some supplemental watering in June.) Second, I wonder if the differences in sun exposure between my garden and yours made a difference. Maybe your sunnier conditions created hotter soil that dried out more quickly.

  4. GARY permalink
    October 3, 2020 10:57 am

    The Asters seem to be exploding this year. There is a farm down the street from me and the whole field seems to be filled with them. Beautiful.

    • October 5, 2020 3:58 pm

      Gary, I’ve been enjoying them along the roadsides here, too.

  5. October 3, 2020 5:10 pm

    Almost all of the horticultural commodities that I have grown through my career have been cloned, either by cutting, or by grafting (onto cuttings of understock). However, palms that I enjoy in my own garden can not be cloned practically. They are all seed grown. For a formal row of desert fan palm, the seed must be collected form the same stable source. Genetic variability is not an asset for such applications.

    • October 5, 2020 4:01 pm

      Tony, A course with Heather McCargo of the Wild Seed Project really shifted my thinking about this. While the uniformity of clones is often aesthetically desirable, genetic variability seems to be better for ecological health. I know I’m not the only one whose thinking has been changed by Heather’s work; at least one local nursery has begun to carry seed-sown straight species plants and these all sell out before the cultivars.

      • October 8, 2020 1:00 am

        The clones that I work with do not worry me because they can not naturalize here, and some had been so extensively bred that they are sterile. However, ‘Soquel’ redwood is a clone that concerns me when it gets planted into the wild. Although the redwood forests do not need any more trees added to their currently crowded situation, people who think of themselves as ‘environmentalists’ sometimes plant landscape trees, particularly ‘Soquel’ redwood, as ‘reforestation’ projects! Redwoods normally clone themselves into potentially large groves, but do not do so extensively throughout the forest. The preponderance of the same clone can not be good, especially since the qualities that make the clone so desirable for landscape situations are not assets in the forest. Because I work within redwood forests, I can see that genetic variability is an advantage in the wild. It is frustrating that so many either do not understand, or do not care.

  6. October 4, 2020 2:33 pm

    Wow Jean, so you now have unique, one-of-a-kind asters in your garden as they have seeded. It’s odd how when some plants go to seed, the seeds are very similar to the parents, while plants like hellebores, aquilegia, honeysuckle etc don’t come “true” from see and you could end up with almost anything.

    • October 5, 2020 4:05 pm

      Sunil, That is so true. I have another native aster in my garden, Ionactis linarifolia that has self-sown in many places, and I can’t see any difference at all among those plants. The New England asters vary not only in color, but also in the width of the petals/ray flowers, and also in height. At least one cultivar, ‘Purple Dome,’ was selected for cloning because it is much shorter than is typical for the species and makes a much neater clump in the garden.

  7. October 18, 2020 9:21 am

    Hi Jean. I love what you have done with these asters. Perhaps the new varieties you have created will also be hardier, since you combined the seeds of cultivars with those of the more native/wild plants. Thanks for the great read and inspiration!

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