We regularly fuss with the top four to six inches of soil in our perennial beds, but what about the soil around the roots?
If some plants don't flower as much as they once did, or are all stems and no foliage, it might be time to move beyond compost and mulch topdressing to truly rejuvenate the beds.
Perennial flower beds can get pretty crowded after just a few years if the plants are healthy and the growing conditions are ideal. And healthy plants use many nutrients from the soil around them. Nourishing the plants with compost and water-soluable fertilizers helps, but within five or six years, the soil could use some help.
Flower beds that have been untouched for many years also need rejuvenating before new plants are added. Untilled soil gets compacted and won't hold moisture or nutrients well, so gardeners need to shake things up a bit.
Once Mother Nature gives the "all-clear" to plant, start digging. By Mother's Day the ground is warm and dry enough to dig.
But don't redo every bed. Make a list of garden beds around the lawn and plan to rejuvenate one every year. For very large beds, rejuvenate them in sections.
Using clean and sharp tools, dig around each plant in the bed, leaving rootballs large enough to minimize disturbance to the roots. Label the plants with their names, the color of their flowers, and how much sun they need. If you liked their placement before rejuvenating the soil, make note of that, too, so they will be returned to the right place.
Carefully put the plants in old plant containers or a wheelbarrow, gently inspecting the roots for damage and disease. Remove any soft roots or insect-damaged areas so they won't be returned to the bed.
Put the plants in the shade, cover their roots with more soil, and keep the roots moist while you work on the plants' new home.
Divide any plants that have overgrown their boundaries and save them for another bed or give them to a friend.
Once the plants have been removed, focus on the soil. To make sure the plants get the nutrients they need, a soil test is in order. I recommend doing this at least every other year. To take a soil test, grab a clean shovel and bucket. Scoop a soil sample from 10 to 12 spots around the bed, being sure to dig down 12 to 18 inches where the roots are. You don't need much from each scoop. Mix all of the samples in the bucket, then spread the soil on a piece of newspaper to dry.
The local extension office can supply the name of a soil-testing location that will tell you how to amend the soil. Make sure the testing location knows flowers or vegetables will be in the bed. Nutrients differ for vegetables, flowers, and turf.
After the soil has been tested, appropriate nutrients may be added to the soil before tilling. As a rule of thumb, the soil will probably need two to three inches of compost and a thin coating of slow-release fertilizer. Gardens with heavy clay may need more compost and some peat moss to lighten the texture. Sandy soils may need compost and clean topsoil.
Till the bed, making sure to break up the big clumps of soil and to remove rocks, sticks, and large roots. The bed should be at least 18 inches deep.
Next, return the plants to the bed. This is a great time to adjust the landscape plan or to add a focal point; to get rid of that "plop garden" theme and coordinate colors and textures, and to sneak a few new plants into the bed. Just slide the newcomers in next to the holdovers, but make sure you cut off the tags from the store first!