Wax Myrtle Makes Its Own Luck

12 Feb

Myrica cerifera (Morella cerifera)

(Cerifera means wax-bearing)


John and George visited Halpatioke Park today in Stuart and pondered Wax Myrtle in full “berry” with newly emerging spring flower clusters, if Feb. 10 is spring.

Wax Myrtle (photo by JB)

Wax Myrtle and Bayberry (M. pensylvanica)—think candles in Cape Cod tourist stops—are close cousins.  Myrica pensylvanica ranges from Canada to the Carolinas.  With a little overlap in range and consequent hybridization, Wax Myrtle (Myrica cerifera) grows from Maryland to Central America.  Thus some folks refer to Northern Bayberry (pensylvanica) and Southern Bayberry (cerifera).

A quick nod to noteworthy relatives:  Myrica inodora, named by William Bartram, lives in and near the Florida Panhandle.  Another Florida resident Myrica heterophylla (or M. caroliniensis, or neither),  lives  across much of the Southeast southward to central Florida.   It differs from M. cerifera by having its leaf glands restricted to the underside of the blade.  The taxonomy and nomenclature of this species is unsettled.  Readers with northern experience may recall Sweet Gale (Myrica gale) and Sweet Fern (Comptonia peregrina).

Bayberry fragrance and wax come from boiling the fruits and foliage, mainly of M. pensylvanica.  You’d have to be a big-time boiler to generate one candle, or you might mix Bayberry fragrance in with a different wax.  By the way, the plants are separate male and female.

The seeds reportedly won’t germinate if not de-waxed, and certain birds do this in their digestive systems.  The Yellow Rumped Warbler has a special taste in its broad diet for Myrica fruits, especially during migration.   Interestingly, they go also for Juniper “berries” too, which are likewise blue, pungent-oily, and wax-coated.    Migrating birds have high metabolic demands and use lipids as stored fuel.

Ecologist Clarmarie Moss devoted a portion of her 1993 Masters Thesis to these berry important matters.  Myrica fruits and Juniper “berries” topped her chart in terms of “optimal lipid profitability.”  She found the range of the Yellow Rumped Warbler tied to Myrica distribution in place and time.  She noted that the mutualism between the two species fits a model known in other bird-plant relationships were the comparatively non-showy and peekaboo fruits in the foliage shadows favor the birds adapted to the relationship.  Preferred customers.

Yellow Rumped Warblers (from Google Images)

Wax Myrtle is clearly a successful species, and as my mother used to say (well, she still does): you make your own luck.   Wax Myrtle improves its habitat by enhancing the soil and by bullying the competition.  Ever wonder why Wax Myrtles are so willing to grow here, there, and everywhere?  They belong to the select group of non-legumes blessed with their own bacterial root nodules.  In our area that clique includes Australian-Pines and Silverthorns, both weedy and tolerant of poor soils.  Oddly, most of the non-legumes with bacterial nodules all share the same bacterium, Frankia alni, a filament-shaped bacterium once thought to be a fungus, and very different from that associated with legumes.  It transforms atmospheric nitrogen to ammonia.

Does the lawn look a little iffy around the Wax Myrtles?  They poison competing vegetation, including pines, grasses, and even Brazilian Pepper.  Experimenters have doused plants with Wax Myrtle extracts and shown the herbicidal effect under “lab” conditions.  It would be interesting to study weed distribution around Wax Myrtles.  The effect may not be 100% negative, since there could be species immune to the toxin and favored by the ammonia-enriched soil.  A project for another day.

In short, next time you brush past a Wax Myrtle, show some respect.  How many shrubs provide aroma therapy, jet fuel for warblers, free fertilizer, and Round-Up-free weed control?


Posted by on February 12, 2012 in Wax Myrtle


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7 responses to “Wax Myrtle Makes Its Own Luck

  1. Steve

    February 13, 2012 at 2:16 pm

    On the southwest coast of Florida, I’ve observed clouds of 1000s of migrating swallows descend on fields of wax myrtles. It was an amazing sight.

  2. annsbirdventures

    March 1, 2012 at 6:21 pm

    I know, I’m overposting, but I just discovered you!
    Another bird that uses the wax myrtles is the tree swallow. Several years ago, I watched a vortex of hundreds of tree swallows descend into a wax myrtle at Loxahatchee National Wildlife Refuge. They were sucked right down into that plant as though a giant vacuum cleaner were at work. It was amazing.
    Ann Weinrich

    • George Rogers

      March 2, 2012 at 9:05 am

      Thanks Ann. If I had another lifetime, so nice to have experts like you and Phil spreading the bird word…such an important component of enviro-education. There’s another comment on swallows below too.

  3. Hope

    August 8, 2014 at 8:29 am

    Hi George,
    I have noticed in field observation and sampling of wild plants that the fruits of rubus that grow among wax myrtles are especially large and sweet; as a result, I began planting wax myrtle as what I hoped would be a beneficial component of our edible, permaculture home landscape. I only select and grow female (fruiting) individuals, not only to attract birds, but also because my husband appears to be allergic to the male’s pollen. I knew about wax myrtle’s potential fire hazard, but was unaware of any potential allelopathic or herbicidal tendencies – wow – thank you for educating me. Would you mind sharing a link or links regarding the herbicidal or allelopathic effects of wax myrtle (are only some competing species affected?). I still love Myrica, and will keep them in my home landscape, but will now research further what I shouldn’t plant around them (what edibles might be negatively affected). Thank you, as always, for illuminating new and fascinating facts about the native species we all may take for granted.

    • George Rogers

      August 8, 2014 at 8:39 am

      Hello Hope, Well, even if WM can be allelopathic, possibly the nitrogen-fixation is the more important “plus” with the Rubus than potential allelopathy. Sounds like thsoe blackberries might be “immune to the toxin and favored by the ammonia-enriched soil.” Probably. I doubt the literature exists to document the differential allelopathic effects on various surrounding species, no doubt highly variable, complex, and context-dependent. The underground battlefield is weird, complex, and very poorly understood. Allelopathy has diverse and sometimes indirect mechanisms (such as causing nutrient depletion), not necessarily outright poisoning to all who draw near, and your cultivated context may well compensate, and blackberries are pretty tough and lively in their own right. Also, the effects can be subtle, at a statistical level requiring measurements. What happens in cultivation can be very different from a natural setting. So many variables. My personal take would be not to sweat it too much…basically, with a little informed caution, I’d use it in the garden happily (I had it in my yard for years), esp. since it seems to get along with Rubus, and if it does fail to play nice with anyone (like your husband’s nose), you’ll have a pretty good idea why.

      • ehopec

        August 8, 2014 at 1:37 pm

        Thank you George! You are so kind to reply…and so promptly! We’re huge fans of WM, and love to have them around….they’re soft, smell good, shed n-rich leaf litter, provide refugia for birds, herptiles…even the earthworms seem to prefer the myrica-enriched soil. The WM seem like such “pure goodness,” it’s hard to imagine a species that they repel….but understand why they might want to limit opportunists that would take advantage of their gracious soil enrichment only to later overshadow them and limit exposure to photosynthesis-maximizing sunlight.

        Just for kicks, it will be fun to start noticing, in wilderness settings, what does and does NOT grow around them….now that I’m aware of their allelopathic/ herbicidal potential.

        The WM givith, the WM taketh away…blessed be the Myrica!


  4. Diane Goldberg

    March 4, 2017 at 10:38 am

    Is there an easy way to tell the males from the females when their too young to have fruit? The City owes me a new bush for one they pulled out by mistake. What should I tell them to look for? The flowers are so tiny.


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