I notice that certain years, certain plants seem to do better than others.
For example, two years ago there was a massive explosion of this native, annual weedy plant Bidens frondosa. There was a meadow near me where it was the dominant plant, and it was showing up all over the place.
The next year though? There was much less of it. This year? Still much less. Both years there were only a few isolated plants, here and there, and it was nowhere dominant.
Sometimes there are factors that I can observe that clearly explain why certain plants do better in certain years. One year there was a spell of about 6 weeks with no rain, and that hugely hindered the growth of plants that rely on that time-period for germination and establishment. I noticed that that year, the drought killed a lot of stuff in spring and early-summer, and annuals that establish a bit later, like Erechtites hierachifolia or the various Acalypha sp. did better that year, whereas garlic mustard was set back, and it also harmed the native black raspberry a lot. Some years are wetter than average and I see moisture-loving annuals like jewelweed moving onto drier ground, or the moisture-loving perennial honewort establishing on usually-drier sites. On consistently dry years I see areas that are normally wetlands filling in with drought-loving annuals like partridge pea.
Sometimes there is a clear masting year for a certain tree, like last year, the northern red oaks in my area were masting, and accordingly, this year, there are a ton of small red oak seedlings everywhere. Two years ago, beech was masting, and I saw more beech seedlings last year, and this year I have not seen a single one.
But sometimes, I’m just perplexed. I cannot figure out why Bidens frondosa had such an amazing year two years back, and why there was so little of it the following year. Where did all those seeds go, did they not germinate? Did animals eat them? Did they germinate but the plants got out-competed? Do the seeds persist in the seed bank and germination only gets triggered under certain conditions, so some years more germinate than others?
Last year, my parsley crop failed. I planted four plants in different location and all four struggled and eventually died. My parents, about 50 miles away, 250 feet elevation higher, completely different soil type (fine, silty limestone-based soils, compared to my coarser, slightly more acidic soils) had the same thing happen that year. Why?
This year, in my area, I notice Elymus grasses (wild-ryes) are doing really well. I am seeing more of them than ever before, of multiple species. I’m also seeing first-year plants with really good seed production, whereas in the past seed production is usually poor on first-year plants.
I want to understand this stuff, and I’m curious for factors to look into other than weather conditions. Are these things affected by periodic insect outbreaks? Our area had 17-year cicadas this year. One year some sort of caterpillar infestation defoliated many of the Catalpa trees, but only those. One year there were a lot of Japanese beetles, and they defoliated certain plants, including evening primroses (Oenothera sp.), Roses (mostly the invasive multiflora rose), and various Hibiscus sp. This year, besides the cicadas, there are no disproportionate insect outbreaks that I notice.
I wonder if there are invisible factors though, that I’m not noticing, like maybe microscopic pathogens that are dominating in some years, or maybe insect infestations going on underground, things eating the root systems of various plants?
I find this stuff fascinating but I feel like I’m barely beginning to understand it because it’s so incredibly complex.