One of the most forward-thinking forms of plant breeding is to attempt to perennialize a plant that exists currently as an annual. Why would you want to do that? Well, first off is that you never have to replant it once you get it established. No replanting means less work for you. The health of your soil will improve, your watering needs will go down and you will get a return crop year after year without issues.
If you are trying to build a forest garden, you will find that many annuals are not able to hold their own in a forest style garden. Annuals are often the pioneer plants that restore open land and fade away once more permanent things get established. This is, in fact, why we regularly till soils to grow them. We are steadily resetting the soil back to a state where pioneer plants are favored.
And should you decide you really don’t care about that, consider that there is a profit to be made selling perennializing varieties of annual plants. There are a surprisingly large number of people biting at the bit for perennial versions of annual favorites. You might find a market for your unique breeds.
So what does it take to perennialize a plant? Well, that depends. If you are in an area that rarely freezes, it could be as simple as creating a microclimate area with thermal mass and similar things. This sort of perennial is not going to be marketable, as it will only function in the microclimate you have created and even then it is hit or miss since some plants will die off even without a freeze. Your greater hope is to grow the plant in a temperate climate in large numbers and carefully observe for the right mutations.
Before you begin freaking out and saying that has to be an impossibility, remember that many plants have an insanely high number of genes in them and only need 2 to move from annual into perennial. That is right, science has proven that an annual will become a perennial in a single generation with the adjustment of two genes. Okay, you say, but how likely is it for that to happen? I just said plants have a /lot/ of genes to work with.
Well, mutations are rare overall, but not in comparison to the number of times cells replicate and the number of cells in total. For every 10,000 to 100,000 replications of DNA, one cell will mis-zip together with a mutation. Most of these aren’t viable and will either be a detriment or even lethal. The cell itself will die off or become a cancer. Poor genes remove themselves regardless most of the time. Good and viable genes however will stick around. So let’s assume your plant in question has between 50,000 and 100,000 (coincidentally the same number as we have more or less). That means that if every cell in the plant divides at once, we would have between 1 and 10 mutations on average. The cells are dividing regularly, so every plant is bound to have a number of mutations. If one of these mutations happens to be part of what we are looking for and is passed onto the next generation, we now have part of what we need. If it happens again, we have the whole thing.
So what do perennials tend to do? Well, they tend to set down deeper roots, especially tap-roots. They tend to flower in the second year or later instead of the first. They often show signs of woody growth. All of these things point towards the storage of energy to last the winter and make it into a new season. If one of your plants is showing such traits, let it go after saving any seed that might occur. If it makes it to resprout the next year, you have a winner and need to start breeding with that plant. I will not go into the details of plant breeding right now, but it is actually not nearly as complex as it is often made out to be.
So now you have some insights into what it might take to turn a temporary plant into a permanent one. Hopefully it was interesting if nothing else. Personally, I love the idea of catching that golden mutation that lets me get a perennial crop from some of my favorite annuals. If I ever have the space to really give this sort of thing a solid go or if I luck into that golden mutation, I will make sure to post it on here with pictures.
