Every forest has a certain amount of turnover during its natural life cycle. Even in rare untouched forests, trees will die or lose branches. From this death comes new growth due the increased sunlight that has now been allowed to break through to the forest floor. Within that much lengthier cycle, there are also seasonal changes that occur multiple times through the year. Each of these changes allow different flora to come to life and to have their chance at dominating their section of the landscape. A wide selection of variables may determine the specifics of these cycles and the cultivars that have the best chance at success. In an untouched system, vigor, among many other variables, will allow individual species to prevail. Usefulness to humans is not nature’s priority. In our food forests and gardens we tend to want to maximize the production of our growing areas in order to reap a bountiful yield. We do not want to leave it up to chance. Our gardens and food forest, however much in disarray they may seem, are fairly organized by us, the planter, in order to maximize production. In most places on earth there is still a virtually endless bank of seeds, rhzomes and other sources of weeds ready to pop up if we were willing to give them a chance - even in our food forests.
In a system that we create with the intention of mimicking nature we need to look at how it handles exposed soil. When the earth becomes exposed to sun and moisture the most likely natural response, as we said above, is to sprout the littles seeds that have been waiting for their turn. The big difference is that we have the ability to control what fills our empty spaces in the landscape before they are taken over. If we have a productive area that sits bald for long enough, it is possible that unwanted weeds will show up. We need to beat it to the punch. You may have heard people refer to this as a cover crop.
This space may not be large enough for a new perennial species to be added to our collection due to competition and spacing constraints. When it is not smart to plant a perennial in this void, it may be wise to resort to planting annuals to temporarily fill in the space and make it productive - and out-compete the weeds.
Annuals certainly shade and can reduce growth of the less desirable species, but there can also be a variety of other benefits that they can provide to adjacent plants. Annual plants can do anything from fixing nitrogen in the soil, to attracting pollinators, to even being a good chop and drop source for mulching around the neighboring plants.
Be creative with your annuals. Many people even put their leftover plants from the vegetable garden in these open spaces. And it’s amazing how something as simple as scattering zinnia seeds, sunflower seeds or throwing a few beans in the ground can increase your yield and hold back the weeds.