The robins are back and soon we'll be back in the gardens. One of the first things to consider in the perennial garden is dividing your mature plants. Dividing overgrown plants can eliminate problems with floppiness, stunted and overcrowded plants. It also brings big plants down to size increasing air flow and light penetration to help reduce disease problems.
Dig and divide summer and fall blooming perennials as they start to grow. Dividing spring bloomers now may delay or eliminate the floral display for this season. Though it won't hurt the plants, you may want to wait until early fall to divide your early bloomers.
Use a sharp shovel or garden fork to dig the perennial to be divided. Dig just outside the outer ring of stems, then lift the clump out of the ground. Use a sharp knife or two shovels or garden forks back to back to divide the clumps. Cut the lifted plant in half, fourths or eighths. The bigger the division the more impressive the show that season and the sooner you will need to divide again.
Prepare the soil before planting the divisions. Mix several inches of compost and a bit or Osmocote or Milorganite into the soil. Place the division into the soil and the previously planted height. Cover the roots with the amended soil, gently tamp to ensure good soil to root contact and then thoroughly water.
You can plant one of the divisions back in the original hole after the soil is amended. The excess plants can be shared with friends and neighbors or increase your perennial garden in another area.