Why focus on annuals versus perennials?
For ecosystem designer and author Dave Jacke, perennials present a wealth of opportunities.
Looking to the future
“We live in an economy, and a time, based on cheap oil. In the future, energy will be more expensive,” says Dave. “We need systems that can meet our food needs and be sustainable. We must learn to live within our energetic means and rebuild ecosystems that support human life without diminishing the ability of the ecosystem to support our children and grandchildren. Perennials can help us do that,” says Dave.
Perennial plants need to be established only once, and yet yield for several, if not many years. This reduces the energy costs and soil damage associated with tillage. Their longer lifespan also helps stabilize the ecosystem, providing habitat for beneficial insects and all-important soil microbes.
“If you are planting annuals you are generally thinking ahead one to two years. By definition, when you focus on using perennials, your planning time frame is much longer,” Dave notes. Planting decisions have longer consequences, and they deserve more thought.
In addition to addressing long term sustainability, a variety of other reasons also make perennial polycultures appealing.
Plant Cooperation not Competition
“Annuals are early succession plants and tend to be generalized species. Perennials tend to be more specialized in their ecological niche,” Dave notes.
The specialized characteristics of perennials can be combined to create great results. For example, different types of root systems can be combined for a wealth of plant cooperation instead of competition. “When you combine deep and shallow root systems, the plants aren’t competing, they are helping each other,” Dave emphasizes.
For example, “most typical fruit trees are flat-rooted, so these combine well with deeper-rooted trees, such as the heart-rooted persimmon or trees that have tap roots such as chestnut or paw paw trees,” notes Dave. Other examples of deep rooted perennials include comfrey and alfalfa.
Many nitrogen-fixing plants are tap-rooted allowing us to reduce competition in the root zone while creating beneficial relationships around nitrogen supplies,” says Dave. Beyond root systems, perennials can be combined based on light tolerances, their relationship with pests and other characteristics.
Pest Impacts Minimized
Each plants’ appeal to pests can be considered during the design of the system. For example, persimmon trees do not attract a lot of pests. Aromatic plants, such as any of the perennial onions and many mints, can confuse pests with their scents, preventing them from finding crops.
The “architecture” of the ecosystem also plays a role. Studies have shown that pests tend to move down rows, and that their progress is halted by changes in the vegetation structure. Mixing up taller and shorter plants in rows can inhibit pest movement and population growth.
Simply increasing diversity helps too. “By mixing a diverse set of plants, the crop plants are hidden from pests,” says Dave. “The pests spend more energy finding host plants. Not only does this open up the pests to more predation it also means they have less time and energy to multiply,” he adds.
Beyond the bad bugs, well-designed perennial polycultures also have an excellent ability to attract beneficial insects, butterflies and birds. “If done well, you can attract important native pollinators like orchard mason bees, shaggy fuzzyfoot bees and bumblebees,” notes Dave.
Many wild predators exist to reduce pest populations, including bees and wasps, predatory flies, various beetles, ambush bugs, and others. Perennial plantings tend to provide better habitat for these insects, and the stable vegetation makes it easier to provide other critical habitat elements these species need too.
Improved food security is a common goal of those looking to perennial polycultures. Crops can include fruits, nuts, vegetables, herbs, mushrooms and other useful plants.
Many also have very high market value. “Blood root not only benefits from shade but has revenue potential because of its high medicinal value,” says Dave. Hardy kiwis, heartnuts, chestnuts, wild leeks, mushrooms, perennial kale, and a range of medicinal plants are also perennial crops that could be marketed.
A Foundation of Soil
“We have to build soils,” notes Dave, “and ecosystems based on perennials are the only natural ecosystems that build soil.”
“Plants plug the primary nutrient leaks from the soil ecosystem. They energize a networked system of plants, soil organic matter, soil organisms, and soil particles that gathers, concentrates and cycles nutrients,” says Dave.
Stronger & Self Sufficient
Perennial polyculture systems are diverse. “It’s about not having all of your eggs in one basket. Diversity can create a healthier, stronger ecosystem if it is done right,” notes Dave.
Perennial polyculture designs are also focused on reducing maintenance requirements. “Stepping back and letting the system do its own thing is a significant reward. It also requires us to take a deep breath and resist the temptation to try and control the system,” notes Dave.
To gain a greater understanding of these and other benefits of Perennial Polycultures Dave will be presenting at the Guelph Organic Conference on Thursday, January 29th.
The session will be designed to be interactive and appeal to different perspectives from that of the home gardener to homesteaders to organic farmers.
Dave is an engaging and passionate teacher of ecological design and permaculture as well as a meticulous designer. He has consulted on, designed, built and planted landscapes, homes, farms and communities in the United States and overseas for over 20 years.
For more information visit http://www.guelphorganicconf.ca/workshops/thursday/
To register visit http://www.guelphorganicconf.ca/register/ and then scroll down to make your selections for the seminar, parking and lunch.
** Please note – Organizers believe the event may sell out and encourage interested individuals to register early to avoid disappointment.
Dave Jacke’s Books
Brad Peterson of Brad Peterson Environmental Management and Landscape Architecture will have limited quantities of Dave’s Edible Forest Gardens two volume set available for sale ($198.45) at the seminar and at the Conference expo in the lower level.
Additional titles by Eric Toensmeier and Wayne Weisman will also be available. Purchasing in advance is recommended. For more details contact Brad at firstname.lastname@example.org or 519-763-5260.
One to One Consultations
Dave is also available for one to one consultations on Friday, January 30th and Saturday, January 31st. Arrangements for these can be made by contacting Dave directly at email@example.com or 603-831-1298.
You Tube Video Links