The analogies of projects are like gardens has gone through a couple of iterations. The first is The Gardening Analogy. Here the conversation is straight forward, a Garden is a systems of interacting elements, from the environment, the machinery of the garden - plants, water, structures that support the plants, and of course the gardener.
Without the gardener, the garden is called weed patch, an open field, a wilderness forest. But one good starting spot is Gardening and Project Management.
The notion that "untended," "emergent," "self organizing" attributes of a system are somehow desirable seems to bit of counter intuitive.
So here's another approach. For my birthday (last Friday) our son gave me a nice book, A Bee in a Cathedral: And 99 Other Scientific Analogies. The first example is the Second Law of Thermodynamics. This law simply says.
Entropy of a closed system never decreases
Entropy is a measure of order, or rather disorder. It is a concept that applies to both information and energy. In the context of the Garden is the "order" of the plants. In the software context, the order of the code, the requirements, to development team, anything related to the project.
A critical notion of the garden analogy, the entropy of the project is that energy is required to decrease the entropy of the system. External energy must be applied to the system.
The gardener needs to "tend" the garden to prevent weeds from taking over, to provide water where there is none, to drain water when there is too much, to fend off bugs, rabbits, and other unwelcome guests.
Another simple example is the Rubik's Cube. Which starts off with each side a solid block of color and when twisted randomly, the colors quickly breakdown and further random twisting will not get the colors back to the original state.
Only with direct, planned, intention, twisting will restore the randomness of the colors to their original state.
For the project, the role of external control is this intention energy applied to the system.
How much energy, when to apply it, in what form to apply it are all context dependent.
Here's a comment to this effect from April of 2009, The Gardening Analogy of Project Management.
