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Month-by-Month Guide to Caring for Your Irises

Here is the useful iris care checklist developed by avid iris lovers, Leon and Norma Vogel, who have a lovely garden in Murrieta, California with their irises planted among many other flowering plants. 

January and February 

  • Fertilize again for the Spring burst of blooms. 
  • Check for aphids that hid all winter at base of leaves. 
  • Discard all dead leaves and weeds. 
  • Check to see if all labels are properly set by proper iris clumps. 
  • Keep irises watered if a dry winter. 
  • Foliar feed for bigger and brighter colored blossoms. 

March and April 

  • Look for first blooms in mid-March and all through April. 
  • Check for aphids and white fly and spray if they are seen. 
  • Water regularly if a dry winter. 
  • Make last foliar feeding for more flowers. 
  • Clean weeds and dead leaves. 
  • Give Japanese and Louisiana iris an application of an acid food -- a camellia-type fertilizer is good. 

May and June 

  • Continue to enjoy lots of blooms into early June. 
  • Check to see if all the iris labels match their name (check bloom description).. 
  • Cut the bloom stalk near the ground when done blooming. 
  • Feed heavily (one tblsp. per rhizome) with 6-20-20 or similar mix when bloom season is over. 
  • Check for aphids near the rhizomes, also for leaf rust. 
  • Keep weeds and dead leaves removed. 
  • Do not neglect to water enough to keep them growing, but be careful not to over-water. 

July and August 

  • Dig clumps that are over-crowded. Divide and share rhizomes with friends. 
  • Dig whole beds if necessary to thin the clumps. 
  • Be sure to add amendments to soil such as fertilizer, peat moss, compost, gypsum and new top soil. 
  • Rototill the soil well and allow to stand for a week if possible before planting new iris rhizomes. 
  • Feed (fertilize) at least 3 times yearly. Foliar feed in between for stellar results. Irises are heavy feeders. 
  • Irises can remain out of ground for 3 weeks or more before replanting. Keep dug rhizomes in cool dry place for storage. 
  • Replant rhizomes, the top 1/4 should be showing above the soil line to prevent rot and allow them to breathe. 
  • Trim the roots back to an inch when replanting-- they send out all new roots within a few weeks. 
  • Do not neglect to water enough to keep them growing. New beds require more water. 
  • Reblooming irises may surprise you with flowers in July-February. 

September and October 

  • Complete digging and replanting of your irises. 
  • Fertilize again. Irises grow all winter long in Southern California. This differs from colder climates where you would want your irises to go dormant in the winter. 
  • Plant any new iris you may have purchased. Label your irises. Be sure mark in water-proof ink. 
  • Keep weeds under control. Check for aphids and white fly and spray with insecticidal soap, if necessary. 
  • Pull off and discard all dead leaves. 

November and December 

  • If for some reason you didn’t get all the things done, it is not too late to fertilize or plant new irises. 
  • Pull weeds as necessary. 
  • Check for aphids often particularly if the winter is mild. 
  • Keep the beds clean of everything except growing iris. 
  • If you have reblooming iris, they need extra fertilizer and water. You can have iris blooms year-round if you include “reblooming” irises.