There are a myriad of ways to conserve energy in your efforts to beautify your home and gardens. Use fewer resources in the garden. Lawn mowing uses up millions of gallons of fuel each year. If you have an acre of lawn to mow there may be other design ideas which will reduce the maintenance required and the amount of fuel used to care for it.
Controlling the light with plants. Design your garden with a sloping planting plan, that is use large trees and shrubs towards the direction of the sun and work your way down to the smaller shrubs and herbaceous perennial and annuals.
Know the sun and shade patterns throughout the year. Tall deciduous trees can create shade in the summer, cooling the garden. They can also block the sunlight from coming through your windows during the heat of the day in the summer months, reducing the need for air conditioning. In the winter, after the trees lose their leaves deciduous trees allow the sun to filter though into the window helping heat house.