easy-to-propagate wildflowers, plus ‘celandine’ confusion, with carol gracie
WHAT SPRING WILDFLOWERS can you multiply easily yourself (like now!)? How long will a young trillium take to flower–and can you really count the little ridges on its rhizome and tell the plant’s age, like rings in a tree? Why do three very different gold-flowered early bloomers—one a tenacious invasive—share the common name of “celandine?” I asked acclaimed naturalist Carol Gracie, author of “Spring Wildflowers of the Northeast: A Natural History” and the guest lecturer at my 2014 June garden Open Day, in a timely native-plant Q&A.
Carol, who was a longtime educator at the New York Botanical Garden and also worked for the Nature Conservancy, has looked beyond the obvious beauty of native plants and studied their life histories, lore, and even cultural uses. I knew she’d be able to answer my questions:
our spring-wildflower q&a
Q. I have easily and fairly quickly propagated a good number of wakerobin or Trillium erectum asexually (by division, as in the photo above) from three lonely refugees I found under my front porch 25-plus years ago. Some of the plants self-sowing, too now, Carol. How does the reproductive life cycle of a Trillium work?
A. Trilliums are a favorite of many wildflower fanciers, so much so that in Europe, where there are no native trilliums, they are sometimes stolen from botanical-garden displays. Of course, wildflowers should never be dug from gardens or in the wild, but trilliums can be rather pricey to purchase at a wildflower nursery. The reason for this is that the plants take anywhere from six to 15 years to grow from seed to mature flowering plant, depending on the species.
However, once you have trilliums established in your garden, they will increase vegetatively by underground rhizomes—and sometimes by seed dispersal as well. Those that develop from the rhizomes may flower the very next year. You may assist their proliferation by digging the plants after they flower, dividing the rhizomes, and planting them in other suitable places in the garden (in dappled shade).
This process is interesting because it allows you to inspect the rhizome and get an idea of how old the plant is. Just count the number of constrictions on the rhizomes, each of which represents one year’s growth.
The ends of older rhizomes often rot away, so this is just an estimate (trilliums are known to live up to 70 years). The one in the photo at left is gauged to be 12 years old.
Like many other woodland spring wildflowers, the seeds of trillium are dispersed by ants—and sometimes wasps—that relish the lipid-rich seed appendages known as elaiosomes and discard the seeds at some distance from the parent plant.
Q. I know that even today, with laboratory breakthroughs in propagation for certain plants and so on, some sources still sell wild-collected wildflowers. How can we know what is ethical to purchase?
A. Other than locating a nursery with a reputable reputation for propagating its own native plant material from seed, or by division of nursery-propagated material, there is no sure way to be certain that the plants being sold are not wild-dug.
It’s important to seek out a grower that you trust—word of mouth is helpful here. Internet searches will bring up sites for individual states that list nurseries certified to follow good conservation practices. But, in fact, there are no propagation police to enforce the rules. Remember: “nursery-grown” plants may have been illegally poached in the wild and then grown to marketable size in the nursery, so the key is to seek out nursery-propagated ones. This is especially true of plants that take a long period to reach flowering stage (e.g., trilliums and lady-slipper orchids).
Q. It can be expensive to get started with spring natives. In terms of making them at home in our gardens, and having success “making more plants” by division or otherwise to eventually get a good show, are there some you’d suggest we start with, and any tips for success?
A. That’s one of the many things that friends are for. A garden full of cuttings, divisions, and extras from friends is not only beautiful, but reminds you of those friends each time one of them comes into bloom. Once your plants are established, you can do the same in a never-ending cycle.
However, some plants just can’t be resisted when visiting nurseries and plant sales. Look for those known to self-sow or vegetatively spread by rhizomes (but not too aggressively, like golden ragwort and Canada anemone, which are pretty but must be kept within bounds or they take over). Good examples are Virginia bluebells (Mertensia virginica) [photo above in Margaret’s garden] and the aforementioned celandine poppy [photo below]–a pairing that I like because they flower at the same time with nicely contrasting blue and yellow flowers.
Creeping phlox is another favorite of mine that does creep to fill shady parts of the garden. Bloodroot (Sanguinaria canadensis) increases easily by rhizomes (again, dig some in the fall, cut the rhizomes into pieces, and move to other parts of the garden). Ants will also aid in dispersing the seeds, providing surprises when plants appear is subsequent years. Although the flowers of wild ginger (Asarum canadense) must be looked for under the leaves, the plants spread easily, making an attractive ground cover in shaded areas.
And mayapple (Podophyllum peltatum) is great for growing as an understory plant in areas where there is enough room for it to spread, mostly by vegetative means. However, last year I had one plant appear 30 feet uphill from my mayapple patch. This year it has multiplied to nine! Since the fruits are eaten by box turtles, I must assume that a turtle planted the digested seed for me.
Q. One of the most common questions I am asked at my May and often June Open Day events is about the swaths of buttercup-gold flowers everywhere. At first quick glance, many people look shocked (as in why did I let that weed take hold?)—and then they look again and realize it’s not the plant they thought. But when I say it’s “Celandine poppy,” that doesn’t quiet their worries—and just further confuses things. Can we talk about “celandine,” good, bad and otherwise?
A. Celandine is a great example of the utility of scientific names. There is just one accepted scientific name for a plant, and it remains the same unless there is a valid taxonomic reason for changing it. However, one species may be known by several different common names—or in the case of celandine, a common name may apply to more than one species, both the good and the evil.
There are three common, yellow-flowered spring species in the Northeast that incorporate celandine into their common names: celandine poppy (Stylophorum diphyllum) [photo above, and in top-right spot in collage below], a lovely native plant in the poppy family with showy flowers; it is a gardening favorite. Celandine poppy is not technically native to New York State, where we both live, but rather to neighboring states south and west of New York.
Greater celandine (Chelidonium majus) [above left] is also a member of the poppy family, with smaller, less-showy yellow flowers. Greater celandine is an introduced Eurasian weed commonly seen along roadsides.
There is also the pernicious invasive lesser celandine (Ranunculus ficaria) [bottom right of collage above], in the buttercup family, which carpets wetland areas in early spring. It is often admired by those who are not knowledgeable about the negative aspects of this European weed. Once lesser celandine gets a foothold [example in photo below], it spreads aggressively—at the expense of all else that has evolved to thrive in the sensitive wetland habitat. Granted, lesser celandine may appear pretty for the brief period that it is in bloom, but it should be removed at first sighting before it takes over.
To confuse matters even further, many people mistake lesser celandine for our native marsh marigold (Caltha palustris), also a wetland buttercup family member with bright yellow flowers. Careful examination of the flowers (usually eight yellow petals and three small green sepals in those of lesser celandine vs. commonly six showy yellow sepals in flowers of marsh marigold) will make differentiating the two species easy. Marsh marigold grows in clumps rather than vast carpets.
(Photos of 12-year-old trillium rhizome, of bloodroot flower with bee, and of confusing “celandines” other than Stylophorum by Carol Gracie.)