Question
A friend gave  me some irises three years ago.  The first year that I had them they bloomed.  Last year and now this year they have not.  I am going to seperate them this year
will that help, if not what can I do?

Answer
Hi Janet,
Thanx for your question.  Irises tend to slow down or stop blooming if they become crowded or if there is disease presence in the rhizomes.  Periodic (once every three years) thinning will help keep the iris patch robust, blooming and healthy.  Iris borers are the most common pest to attack irises.  Dispose of all diseased rhizomes and either burn or send to the rubbish.  Do not compost as this will not guarantee the pests' demise.  Too much shade and too much nitrogen will also deter blooming.  Has the iris patch become more shaded with the growth of nearby trees or shrubs or new construction?  Have lawn chemicals possible seeped into the iris patch?  Lawn chemicals are very high in nitrogen which encourages green, leafy growth at the expense of floral growth.  Best time to move irises is late summer or early fall.  I hope this helps.
Tom