PDF download Download Article PDF download Download Article

Irises are beautiful flowers that are easy to care for in your garden, but they can be easy to forget about once summer ends. To keep your flowers in tip-top shape, get in the habit of trimming back your irises every fall so they grow back once warm weather arrives again. If your flowers seem a bit overcrowded, take some time to divide and replant them so each iris can get plenty of nutrients. This task doesn’t require a lot of gardening experience, and can be completed with common gardening equipment, like pruners and a gardening fork.

Method 1
Method 1 of 2:

Trimming Your Plants

PDF download Download Article
  1. Keep an eye on your iris plants even after they stop blooming. Look for leaves that are visibly broken, along with leaves that show signs of disease. [1] Take a pair of bypass pruners and clip these leaves down so they only stick 2 in (5.1 cm) out of the ground. [2]
    • Cutting back damaged or sickly iris foliage can help prevent the disease from hurting your plants in the next growing season.
  2. Check on the weather reports throughout the week. Specifically, wait for the first few frosts to arrive, which will kill off most of your iris foliage. Once most of your leaves look brown and dead, set aside some time to trim your plants. [3]
    • Make a note on the calendar each time a frost occurs. Once 3-4 frosts occur, you can get ready to cut back your irises.
    Advertisement
  3. Take a pair of bypass pruners and cut straight across each iris leaf. Leave about 2 in (5.1 cm) of leaf sticking out of the ground, so the plant’s roots don’t have to expend energy keeping the leaf alive. Repeat this process with all of the other iris plants in your garden. [4]
    • Any kind of shears of trimmer will work for this, as long as it cuts your plants in a straight, even line.
  4. Cut along the left and right sides of your trimmed iris plants at a 45-degree angle, which creates a fan shape. [5] This helps make your irises look more uniform, and can prevent diseases from spreading on the leaves.
    • This is more effective if you have a lot of irises in your garden. If you only have a few irises, it won’t make a huge difference if you fan the leaves or not.
  5. Collect the leaf trimmings in a trash bag as you cut them off. Toss the leaves out completely, or add them to your compost bin, if you’d like. [6]
    • Double-check your town’s compost regulations before adding anything new to your bin.
  6. Give your plants time to recharge and grow back with fresh, healthy leaves and buds. Keep in mind that you probably won’t see any progress until springtime. [7]
  7. Advertisement
Method 2
Method 2 of 2:

Dividing Irises to Prevent Overcrowding

PDF download Download Article
  1. Wait for your irises to stop blooming, which will be sometime in the late summer months. This time period is the best, as your irises won’t be as likely to develop any bacterial rot. [8]
    • Ideally, you should divide your irises every 3-5 years to prevent your flowers from overcrowding one another. [9]
    • Don’t divide your irises in winter—at this point, they’re just starting regrowth, and dividing them will cause a setback.
  2. Take a pair of bypass pruners or shears and cut in a straight line across your irises. Cut the entire plant back enough so it’s much shorter, or about â…“ of its original height. [10]
    • This will make it easier to dig up your irises, and will help your plants focus on nurturing their roots instead of their leaves.
  3. Stick a large garden fork beneath the soil of your irises. Lift slowly and carefully to remove a clump of flowers from the ground. [11] Set this clump aside in an open area where you can examine and sort each flower. If you have multiple groups irises in your garden, remove all of them with a pitchfork. [12]
    • Because of the way they grow, all of your irises will be in clumps instead of growing as individual flowers.
  4. Remove your trimmed flowers from the clump and pull apart any irises that are stuck together with your fingers. Note that each iris should have a thick, healthy rhizome, or plant base, along with multiple thin roots threading out from the bottom. [13]
    • The goal of this process is to split apart individual rhizomes, which will make your irises easier to replant.
  5. Brush off any dirt and rinse off each individual plant in an empty bucket or basin and look for any signs of rotting or infestation. If the plant looks healthy, set it aside for replanting. [14]
    • Watch out for iris borers, which are white worms that feed on irises.
    • Unhealthy or rotted rhizomes tend to have a foul odor, and may feel really light or hollow.
    • If you’d like to go the extra mile, you can sanitize your shears or cutting tool with a mixture that’s 9 parts water and 1 part bleach. This will kill any potential bacteria and make the division process more sanitary.
  6. Place the base of the rhizome about 1 in (2.5 cm) or so into the soil. Separate the roots so they’re ready embedded in the soil, but leave a few millimeters of the rhizome peeking out over the soil. [15]
    • The rhizome is brown, while the rest of the iris plant is green.
  7. Take out a measuring tape to ensure that your irises are evenly spaced and separated in your garden. This will help prevent overcrowding, and will make sure that your flowers can plenty of nutrients. [16]
  8. Fill up a watering can and water each iris until the top 3 in (7.6 cm) of soil is damp. After this, leave the irises be until the weather is dry and warm. [17] You can cut back on watering if you experience a lot of rainy weather. [18]
    • Irises need to be watered on an as-needed basis, but not daily.
  9. Advertisement

Expert Q&A

Ask a Question
      Advertisement

      Video

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Thanks for submitting a tip for review!
      Advertisement

      Things You’ll Need

      Trimming Your Plants

      • Bypass pruners
      • Hedge clippers (optional)

      Dividing Irises to Prevent Overcrowding

      • Bypass pruners or clippers
      • Garden fork
      • Basin or bucket
      • Water
      • Watering can
      • Measuring tape

      About This Article

      Thanks to all authors for creating a page that has been read 77,977 times.

      Did this article help you?

      Advertisement