Double helix garden design occurs when you lay out the pattern of your garden with two intertwining lines. The lines can be structural elements like bricks or rocks or the plants themselves. The twisting lines create separations, allowing you to highlight certain flowers or separate flowers from edible herbs and vegetables.
Measure the planting area to determine how to design the double helix garden. If it's a long and narrow space, plan on making the edge one side of the double helix and one curving line in the middle of the garden as the other side of the design. If the garden is large, you can create several double helix designs.
Sketch the double helix design on paper before beginning in the garden. Lay out where you want the double helix to start and stop.
Use a can of outdoor spray paint to create the double helix design. Start the line on the left side of the garden, and move the can in an upward motion, creating a wavy pattern. Continue it by moving the spray paint in curvy lines, somewhat like waves.
Start the second part of the double helix at the same spot on the left side. This time go downward with the spray paint, then back upward. Cross over the first line, creating the double helix design.
Place stones or bricks along the double helix you've drawn. You may also choose to plant individual flowers or vegetables along the lines, using them to create the design.
Plant other types of plants throughout the garden. Use the double helix as a separator, allowing you to segregate certain flowers. This will serve as a way to highlight them.