While arguments can be made in favor of annuals, this little manifesto lionizes perennials. Perennial plants are hard working plants that survive for years, which means they mazimize your benefits (from enjoyment of flowers and edibles) while minimizing plant maintenance and the negative effects of disrupting your soil. Good things live in your soil, things that pass on valuable information from one plant generation to the next, and responsible planting can help maintain healthy habitats.
Plant Once, and Grow for Years
It's kind of like the old saying, "buy once, cry once." You may spend a little more on a perennial than you would on an annual plant (and maybe cry about the cost), but you will reap the benefits of enjoying the perennial year after year, while you will likely have to replace annuals each growing season. (The exception being self-sowing annuals, like snap dragons and sweet alyssum, and planting tropical plants in a zone with no frost.)
There are more than financial reasons to plant perennials, rather than annuals, though. Digging up your earth (tillage) each year to plant new annuals releases Carbon into the atmosphere. Additionally, tillage can harm beneficial organisms living in your soil. It particularly disrupts the complex communication between fungi that live in your soil and help plants thrive.
There are beneficial fungi that live in the soil called mycorrhizal (or mycRorrhizal; I've seen it both ways) fungi, which are enormously important for both the soil condition and the health of plants. These fungi are very similar to the extensive communication system between plants and trees depicted in the movie "Avatar" (Hollywood actually got something correct; well done).
Mycorrhizae are amazing transmitters in the soil. They help move and distribute nutrients throughout the soil, reducing the need for externally added fertilizer. They also transmit warning signals when plants of the same species (there is some evidence that mycorrhizae may transmit them across species, too) are attacked by disease or insects. When one plant is harmed by disease or pests, it releases chemicals in its defense, as well as warning signals that attached mycorrhizae transmit to plants of the same species in the area. The uninjured plants pick up the warning signals and produce defense chemicals that reduce their susceptibility by innoculating them against the attack. What's more, mycorrhizae fix Carbon in the soil, lessening atmospheric Carbon emissions.
Digging in your garden every year will disrupt mycorrhizae and potentially kill them, which can open up your plants to greater susceptibility of disease and insect attacks. Massive scale farming practices tillage, which is a large contributor of Carbon emissions, in addition to being a destroyer of mycorrhizal colonies in the soil. Because of this, crop issues have spiraled downward (plants are more susceptible to disease and pest attack, so farmers use harsher chemical pesticides, those chemicals runoff during heavy rains into local watersheds, contaminating water and harming the fauna, humans and animals may actually ingest the fauna that has ingested these horrible chemicals... get the point?), negatively impacting our watersheds and beneficial insect populations. Erosion, pesticide/herbicide use, invasion of weeds, and compaction are a few other things that harm a soil's health and the health of the helpful organisms that live there.
Welcoming the Fungi
Mycorrhizal fungi will appear on their own in your garden if you allow perennials to grow undisturbed in your garden, but they may take years to arrive. To speed things along, you can buy inoculant, which has fungi spores of several species.
However, keep in mind that your soil probably already contains some mycorrhizae, and that because mycorrhizae are heat sensitive, the ones you can order may be dead before they make it to you (if, say, the truck carrying your package is left in hot weather too long). Furthermore, it is always a risk (of varying magnitude) to import foreign things into your garden, and unless you know exactly which mycorrhizae you are importing, there is always the possibility of disturbing a natural balance.
To encourage mycorrhizae to move into the neighborhood of their own accord, provide them with a welcoming environment by planting perennials and trees, and then leaving the soil be.
So you want to keep your soil healthy, and improve your plants' resistance to disease and pests, you say? Perennials are just what the doctor ordered.
Here are a few things to keep in mind when you choose your perennial garden plants:
-Survey your land for sun/shade and water retention,
-Stagger heights and blooming times of perennials in each bed to maximize pollinating time and beauty throughout the year,
-Keep in mind shrubs and trees for nesting sites,
-Incorporate perennial vegetables in your plantings to reduce the burden on your annual vegetable garden site.
All the Colors
Many people plant annuals for the color, but when so many perennials also provide colorful blooms, you can stagger bloom times, and you do not have to go to the trouble of planting new ones each year, why would you plant annuals?
These are just a handful of perennials you can plant for color:
Some perennials are even edible:
You may have heard the argument to become a vegetarian explaining that not eating meat reduces our negative impact on the earth through a chain of cause and effect; growing perennial vegetables takes that up a notch. By growing perennial vegetables (and fruiting trees), not only are you are lessening your dependence on annual gardens and reducing the Carbon emissions mass farming releases through annual tillage, you are actually helping fix Carbon in the soil. Bravo!
Less Weeding to Do
Perennials additionally demonstrate their good qualities by reducing the amount of weeding you have to do once the initial wave of weeds are pulled after planting. Make sure you pull those initial weeds before they can flower, though, otherwise you'll run the risk of letting them self-seed and propogate. Also, if you plant your perennials as close as spacing allows, you'll further reduce weeds because they cannot reach sunlight through your stronger-growing perennials.
On a separate, but related note, mycorrhizae play an important role in the health of our forests. In forests, old trees, called Mother Trees, are necessary for passing along knowledge through mycorrhizal fungi to foster regrowth of forests.
The Mother Trees literally pass on knowledge of survival to the younger generations of trees. And when we cut down these Mother Trees, the younger trees' survival rate is diminished, both because we have removed the source of ancient botanical data, and because we have disrupted the mycorrhizae. Scientists are fortunately studying the importance of Mother Trees, and we can help spread the word by learning more and actively discouraging deforestation.
Exultation of Perennials
Have I praised perennials glowingly enough? Go ahead and plant a few annuals in pots, but plant those hard-working perennials in your garden beds and help out your mycorrhizal fungi populations. Over a few years, you'll see a difference in the overall health of your microenvironment, while you sit back and let your garden grow beautifully.