A recent piece in the Washington Post about the seed bank that sits dormant in our landscapes has me thinking a lot about seeds as I weed and work in the garden. It also informs how I may approach managing my landscape in the present and for the future.
As any gardener can observe, our gardens and landscapes are not simply filled with the individual plants that we are cultivating, but the soil is filled with dormant seeds that will sprout and grow when their conditions for germination are met. This is both a blessing and a curse, and occasionally somewhere in between. When the seeds that germinate are invasive weeds,such as garlic mustard or oriental bittersweet, it just means we will have more weeding to do in the future. If the seeds are those of natives such as wild geranium, native asters, or Jacob’s ladder, we may see it as a net positive, depending on our plans for that area. And sometimes it brings along a plant that may be native, such as pokeweed or jewelweed (also known, for some odd reason, as spotted touch-me-not), and a gardener may see this positively or negatively depending on one’s opinion of such plants and their place on one’s property and how they meet the needs of local wildlife and pollinators.
This seed bank is a collection of seeds that sits dormant beneath the soil’s surface and builds up over the years. It is simply waiting for the seeds to be given the water and light they need to leave dormancy and push forward their seed leaves to the surface. From there, the seedlings will mature, flower, and set seed—replenishing the seed bank from which they came. One of the most famous displays of such a seed bank in action is often referred to as the Super Bloom in the California desert, which comes on when heavy winter rains bring a flurry of growth to the desert. In this case, many of the plants that come forward, such as California poppies, are annuals, but seed banks also contain seeds of biennials, perennials and woody plants that will begin their longer life cycle after breaking dormancy, provided conditions support them.
Ecologists and evolutionary biologists are starting to study how these banks can be used to restore landscapes that have been overrun by invasives, examining whether the seeds from these seed banks are more effective in restoring a landscape than the introduction of seeds from another source, as the seeds that are in situ have evolved on that site to meet its specific conditions. Though these conditions may be evolving with changes in weather patterns, it is hoped that the seeds will be adaptable and will help in the restoration of wild areas. I know that whenever I leave an empty space behind on my property, I will find something moving in to appropriate the site with lighting speed. I only wish that I liked more the celandine poppies that move in, and that the other self-sown plants, such as Jacob’s ladder and native phlox, were as aggressive as the celandine poppy and the pokeweed. However, I am greatly pleased when I find an occasional perennial, such as amsonia or baptisia, making its way forward, sometimes leaving it in place and on other occasions moving it to a more desirable location.
These seedlings have me thinking differently about how I approach the care of my landscape as well. If I am going to cede some land over to the seedbank that lies beneath it, I want to ensure that the seedbank is primarily made up of plants that I hope to have in my garden. The best approach to this is twofold. First, ensure that undesirable plants—and this can range from aggressive exotics such as bittersweet to the aforementioned native pokeweed—are edited from the landscape before they have time to set seed. This can be done by weeding, or string-trimming the plants before they set seed, if weeding is not going to happen in time. At the very least, by doing this, I am lessening the percentage of these undesired seeds in the composition of my seed bank and in my basket of weeds removed each subsequent season. Second, allow your preferred plants to set seeds each year to replenish the seed bank, whether they were re-introduced into the landscape by you or were the product of the seed bank they are adding to.
In advising an overwhelmed neighbor the other day, I simply told her to begin removing what she doesn’t want and allowing what she does to move forward. When I received a text from her the next day, telling me how relieved she was to begin with this simple approach, I knew I was on to something. One could say I had one in the bank.
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A gardener grows through observation, experimentation, and learning from the failures, triumphs, and hard work of oneself and others. In this sense, all gardeners are self-taught, while at the same time intrinsically connected to a tradition and a community that finds satisfaction through working the soil and sharing their experiences with one another. This column explores those relationships and how we learn about the world around us from plants and our fellow gardeners.
