What would it say? In this forest I can imagine it saying “give me shelter”. Pale Jewelweed’s just a humble annual plant, so weedy and abundant we don’t usually give it a second glance. But deer relish its juicy tenderness; by midsummer in this forest, any unprotected Jewelweed is looking seriously ragged.
Jewelweed might also say; with only one season to get it done, you have to be up early. As one of the first soft new things to push itself up, Jewelweed’s bright yellow-green leaf circles are everywhere in early spring.
Before deer arrived, by June there used to be a dense cover of this plant on much of the floodplain. One more thing Jewelweed can tell us is how fast the deer population is increasing.
This particular patch, including some False Dragonhead, Physostegia virginiana, is in an area off limits to deer for the past several years.
This unprotected patch has been browsed through the summer, and will not produce the lovely orange flowers beloved by hummingbirds.
Can the deer in this forest eliminate the Jewelweed? They will reduce populations severely, but fortunately this weedy annual has some intriguing defensive tricks up its stem.
In the plant world, as elsewhere, sexual reproduction is an energy expensive task. If a plant doesn’t have the energy to produce pretty flowers due to drought, browsing, etc, it needs another way to get the job done. This is especially true for annuals, with their do-and-die cycle. The solution for some is “cleistogamy”, or selfing – seeds that are genetic copies of the parent plant formed in tiny colorless flowers. No pollinators required! In fact, research has shown that most of Jewelweed’s seeds are produced this way. So even a deer-ravaged plant with no obvious flowers can produce seed. A research study (link below) even found evidence that populations of Jewelweed which have been exposed to browsing over long time periods can cope with it better than ones that were protected. http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12344/pdf
Though selfing is good for the plant’s long term survival, the absence of nectar-filled flowers is a real loss for hummingbirds and other pollinators. In the time before deer in this forest (20 years), one could walk the trails in late summer and expect to hear the fine twittering of hummingbirds in the adjacent lush stands of Jewelweed. These days, the few unbrowsed stands are either naturally, or “intentionally” inaccessible to deer. For Jewelweed to thrive in this forest now, it needs a little help from humans.
This little hummingbird happy spot was partly blocked by the log, then “enhanced” with dead limbs of Bush honeysuckle.
On the unprotected right side of the log, a different story; invasive Stilt Grass, Miscanthus, is getting a foothold without shade and competition from Jewelweed or other native plants. So when deer eat enough tasty natives, they actually open the door to exotics such as Garlic Mustard, Privet, Bush Honeysuckle, Stilt grass, etc. – all of which are avoided as food.
As an annual, Jewelweed depends on its seeds. An alternate name “Touch Me Not” is a misnomer, since the plant would rather be touched. It’s ripe seed capsules then snap open with such force that seed is ejected out many feet from the parent plant
In a way, Pale Jewelweed is speaking to us, retelling the ancient story of herb vs herbivore. This never-ending struggle gets played out on a tiny scale in our forest every season. Are we listening?
more tricks up its stem