Creating a Garden Border: When should I start in the spring? You can start planning indoors on paper in January Outdoor work can begin as early as March in the Midwest, or as soon as the ground is thawed.  The layout work can be done as long as there’s no snow on the ground so you can see what you are doing. Planting is best to be done in the spring for Herbaceous Perennials.  Trees and shrubs can be planted in the spring, or fall for the best success rate.  You can still plant in the summer, but you have to be religious about remembering to water to protect your green investments! 10 Steps to Getting That Garden Started: Be sure to have all your utility lines flagged before you start! Lay out the flower bed with a garden hose to achieve the shape. Then spray Roundup on the grass now to kill it off. Or, if you don’t want to mess w/Roundup, lay out the bed w/garden hose…spraypaint the border, Rent a sod cutter …