How Do You Know It's Time to Divide Perennial Plants

  • 01 of 03

    Center of Plant is Dying Out.

    The dead center of this ornamental grass is a dead giveaway that it needs to be divided.
    How Do You Know It's Time to Divide Perennial Plants The dead center of this ornamental grass is a dead giveaway that it needs to be divided. Photo: © Marie Iannotti

    Many perennial plants can live for years without division. Some perennial plants even resent division, mostly those with long tap roots or woody crowns, like Russian Sage and Baptisia. But most other perennials will eventually deteriorate, if left to grow indefinitely and benefit from being divided, either to rejuvenate them or to keep them from being squeezed out of the garden. There are 3 basic reasons for dividing perennial plants:

    1. To make more plants
    2. To revive an older plant
    3. To keep the plant’s...MORE size in check

    You can divide a large plant anytime you want to make more plants, even when you first bring it home from the nursery. In fact, buying a large plant can actually be a way to save money, if you plan to divide it into many plants immediately.

    But how do you know when your mature garden plants need division? They’ll show you with the following signals.

     

    Your Mature garden plants will give you signs when they need to be divided, but it’s always best to try and get them divided before these signs appear. A sign that a plant needs division is also a symptom that the plant is struggling. If you can avoid that by dividing your plants in a more timely manner, your plants will be healthier.

    Signs a Perennial Plants Needs Division Now:

    1. Dead Area in the Center of the Plant

    As plants grow, they tend to spread out from the center. Eventually the older, center section will get woody and die out. This dead core will never regrow, the plant will just continue to grow out from the sides or decline altogether.

    You shouldn't wait until it gets this bad before dividing. Once you see the center dying out, you can either chop off the healthy side pieces to move and replant or lift and divide the whole plant. Either way, discard the dead center.

    Continue to 2 of 3 below.
  • 02 of 03

    Splitting Open from the Center.

    Plants that split open in the center probably need to be divided.
    How Do You Know It's Time to Divide Perennial Plants Plants that split open in the center probably need to be divided. Photo: © Marie Iannotti

    Signs a Perennial Plants Needs Division Now:

    2. Plant is spilling apart in the center, probably flopping over.

    Even though the center of the plant doesn’t appear to be dying out, the plant is still fading away in the center. This plant is on it’s way toward have a dead center core. The outer stems are sturdier than the center stems and a once upright plant can now barely support itself. Yes, some types of perennial plants simply need staking, but if you have a plant that has been supporting itself...MORE for years and has suddenly begun flopping open in the center, it needs division.

    Note: Plants will reach toward the sun and appear to be flopping, but the whole plant will flop in the direction of the sun. Plants that need division will flop open from the center.

    Continue to 3 of 3 below.
  • 03 of 03

    Less Flowers than Prior Years

    Coreopsis that Need Division because it is not blooming profusely any longer.
    How Do You Know It's Time to Divide Perennial Plants This Coreopsis plant is baring blooming. It would benefit from division. Photo: © Marie Iannotti

    Signs a Perennial Plants Needs Division Now:

    3. Blooming is becoming sparse and flowers may be smaller.

    This symptom is the hardest to detect. It can be a subtle change, but eventually you’ll become concerned that your plants just don’t bloom as much as they used to. If nothing else has changes, such as more shade from growing trees or lack of water, it is probably a symptom that the plants needs to be revived by division. The poor plant is exhausted and needs some rejuvenation.

    Tips for...MORE Successfully Dividing Perennial Plants

    1. Spring is the best time to divide most plants. Fall is the 2nd best time.
    2. Replant ASAP after dividing, even if it’s in a temporary spot or pot.
    3. Divide and replant on cool, overcast days. If that’s not possible, at least give the plant some shade.
    4. Water the plant well the day before division and don’t let the roots dry out.
    5. Keep the plant well watered, at least until you see signs of new growth.