A Gardener’s Diary: Bearded irises are easy to grow

Jocelyne Sewell offers tips to grow these colourful perennials

September is at the door and I am hoping it brings cooler temperatures and the rain we so much need. I intended to divide my irises starting in July but here we are at the end of August and only a few have been dug out.

There are many groups of irises but today I will write about bearded irises. They are easy to grow and in no time, you will have enough to share with friends. They bloom in late spring and can give quite a show of rainbow colours. Sometimes they are also called German irises. They are very hardy plants and they don’t complain too much even when some weeds grow with them. They were growing very nicely on Bella Vista Road until road works destroyed some of them. I noticed this spring that some were blooming again.

Bearded iris roots are called rhizomes and they should be partly exposed to the sun. If they are planted too deep, it might inhibit blooming. Of course, they can break the rules as I see some on the banks buried and still blooming.

Bearded irises should be divided every four to five years so that the weak rhizomes can be removed and the soil can be improved at the same time and fertilized. The best time to do this is about four to six weeks after they have finished blooming. Choose only the best ones for transplanting. Add bone meal over the spots and work it in. They like an addition of compost and the soil should have good drainage as it will protect them from root rot. I lost a few that were at the bottom of the bank where some of the water accumulated and they just rotted away.

Each rhizome will only produce one flower stalk. New rhizomes grow from the side of the main one and will produce flowers later when mature. If they are not divided, they grow into each other’s path and on top of other rhizomes and become overcrowded and will starve for the lack of soil nutrients. The blooms will get smaller and some of them might never bloom.

This is the latest time now to transplant your bearded irises for them to put new roots in the new location and have time to establish themselves before the frost. There is a possibility that some of them might not bloom the following year after transplant. Just be patient and it will happen. When you dig up the clumps, just wash them and you will see the old growth and this should be cut off and discarded. A small knife will do a clean job. You will see some brown roots with no life and this is where I usually cut off the rhizomes. The really small rhizomes are not worth the bother. The mother rhizome will never bloom again but I find it gives stability to the ones growing from the sides. You can always cut them off after they are well-rooted.

Do not cut off the leaves unless they are brown. Remove the dead ones but keep as much of the green ones, as they feed the rhizome. Cut off the spent flower stalks. Cut off also the dead roots but leave the other ones. Spread the roots and bury the rhizomes but leave the top showing. I have lots of purple ones and they are free for the taking. Just phone me.

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