Dear Members,
When I last wrote to you, my garden seemed dead. A few Hepatica acutiloba (sharp-lobed hepatica) flowers were coming up, but little else was happening. I had hoped the cold, snowy winter—like the ones I remember from my youth, before the climate seemed to go haywire—would have been good for the garden, but the herds of deer that roam our town were ravenous and devoured my Rhododendron maximum (rosebay rhododendron) and Kalmia latifolia (mountain laurel), plants that are toxic to them. The nets I hurriedly threw over the plants didn’t help once the snow weighed them down and the deer could reach the leaves again.
Today, the shrubs still look butchered, and some are bound to die, but at ground level, the garden is in full bloom. Thousands of spring ephemerals and ferns are reminding me that life comes back, so long as it is tended and protected. Mertensia virginica (Virginia bluebells) are spreading into blue drifts across my forest floor alongside Podophyllum peltatum (mayapple). Trillium spp. (trilliums) are blooming everywhere, while Sanguinaria canadensis (bloodroot) and Jeffersonia diphylla (twinleaf) have already had their brief blooms. Matteuccia struthiopteris (ostrich fern) is nearly full size, while Polystichum acrostichoides (Christmas fern) and Osmundastrum cinnamomeum (cinnamon fern) are beginning to unfurl. This is the narrow window before the trees leaf out, when sunlight still reaches the ground, and the forest floor can flower—one of the most beautiful times in the native plant year.
The tragedy is that it would be hard to find anything like this in most forests and parks in our state. In too many places, the spring flora has been browsed down by deer and eradicated. Deer browse is a huge problem for native plants in our state, more immediately destructive to the forest understory than climate change. Climate change alters the conditions under which forests grow, but deer can turn the next forest into a veritable biodiversity desert, browsing down native plants while leaving invasive species behind. Due to the topography of my yard, I can’t build a deer-exclusion fence, but a maze of Orbit Garden Enforcer motion-activated sprinklers protects most of my plants during the growing season, allowing my garden to function as a small refugium in a state that now has more deer than at any time before European colonization. Without that protection, much of what is flowering here would simply be gone.
Sadly, the problem isn’t limited to New Jersey. On a recent trip to Japan, I saw how sika deer—native there, just as white-tailed deer are native here—have damaged forests and wetlands when their numbers rise beyond what the land can bear. In parts of Nikkō, deer browse has helped turn the understory over to Sasa nipponica (dwarf bamboo), a native plant that can form dense, persistent carpets and suppress much of the rest of the forest flora. The lesson is not simply that deer are a problem. It is that a species does not have to be non-native to become ecologically overwhelming. We have smaller warnings here—Dennstaedtia punctilobula (hay-scented fern), for example, can expand after heavy deer browse and disturbance—but Japan shows how severe native super-abundance can become when the checks on abundance disappear. I won’t usually promote my own website in these letters, but if you are interested in this topic, I wrote about it in greater depth on my blog.
Humans are part of this story, too. We are not outside nature looking in; we are a native species almost everywhere we live, and the most super-abundant native species of all. Super-abundance of deer is a crisis we created by exterminating predators and then avoiding difficult management questions for decades. If we care about spring ephemerals, birds, forests, and the future of native plants, we have to talk honestly about native super-abundance—and our role in creating it. Until then, all we can do is build refugia.
I also want to offer an apology about this year’s Native Plant Month BioBlitz. I had not realized that the project was set to exclude non-native and cultivated species. That was my mistake. Native-only data is valuable, but so is the broader record of what is actually growing in New Jersey—native, introduced, invasive, and cultivated. Next year, we will plan for two concurrent BioBlitzes: one focused on native species, and one open to all plant observations. Both kinds of data matter.
Thank you to everyone who observed, planted, taught, volunteered, and paid attention during this National Native Plant Month.
Happy gardening,
Kazys Varnelis, Ph.D.
President,
the Native Plant Society of New Jersey