Spending time in natural areas helps us feel that we are part of something bigger than ourselves. Giving our effort in accordance with the health of our environment can further relax our sense of separateness. Being outside can come as a privilege or hardship in passing swells, and returning to the reality of our work as an integrated and continuous aspect of the whole of the land can calm these beguilements.
The old borrow pit pictured above was just treated with a seed drill containing 55+ species of native herbaceous plants. It has been bare for decades, and several springs emerge from this slope during exceptionally wet periods. That is a long time for a wet site to stay bare. The seed drill breaks the soil crust while it plants the seed, but if nothing takes, some sort of organic material or soil amendment may be due.
Seeding in April, though perhaps a little behind the curve, is not without its advantages. By this time of year, many sites that have at least some vestige of an appropriate seed bank have already started to green up, and so those bare patches in greatest need of additional seed call loudly out to us from across the property. “Over here, dumb@#$!”
When we seed in the winter, we allow some time for cold stratification and seed coat-weathering (which may or may not matter for a given species or in this particular central Texas clime). Perhaps most importantly, we also allow some time for cool-season (C3) species, like Bluebonnets, Cutleaf Daisy, Texas Yellowstar, Melicgrass, and Canada Wild Rye, to take full advantage of mild weather at the turn of the seasons.
A risk of seeding in the winter though, is that prior to spring green-up, we might mischaracterize which sites our seed will have the best chance of surviving in. Seed banks can contain thousands or tens of thousands of viable seeds per square meter, so another handful of our stuff might not have much of a chance. Seeding in the spring can help with this problem.
There are a few species that we leave out of our general seed mix, such as Switchgrass, which can establish from seed on sites radically unlike their native niche, and dominate those sites at the expense of diversity. There are others that we include in the mix despite that we anticipate only a few of the seeds will establish, like Inland Sea Oats, which requires more shade than many (but not all) of the sites we seed.
We also include species that can establish well outside of their niche, but that do not seem to be invasive (and thus not to hamper diversity). This is maybe the most interesting thing that happens when we seed a site with our high-diversity wild-harvested mix. A few years ago, we learned that Melica could behave this way. Recently I discovered a dry, rocky hilltop we seeded a couple of years ago after a summer burn that reduced canopy cover substantially. The area was sparsely populated with bushy bluestem (a strictly riparian species, under normal circumstances). Then I found a seasonal head-water seep on the south facing slope of the hill:
These kinds of occurrences are most interesting because of the questions they beg: after establishing broadly, will they persist? Will they eventually contract to the part of the site that is most like their native niche? Will they migrate to the nearest occurrence of their niche (in this case, down-drainage)? Why did they establish where they did and not elsewhere? Was it random? Or the work of some unknown series of filters? A little odd, but still so neat.
This time of year, late March into mid-May, is perhaps the best time of year to manage non-native invasive species. Let me count the ways:
- Plant metabolisms are highly active as they transition out of winter dormancy. The movement of fluids makes plants vulnerable to treatments that work on vascular tissue, like girdling and herbicide.
- Plant species become easier to identify as they put on new growth and even flowers.
- If you are working on finding and treating them as new foliage and flowers develop, you can get to them before they produce ripe seed, which will be helpful in follow-up treatments.