Choose and prepare your iris flower beds now for July planting

Bob Dluzen
Special to The Detroit News

Our earliest bearded irises have started blooming just in time to add color to the garden as the last of the spring flowering bulbs are fading. As such, they occupy a valuable niche in the flower garden timeline.

Other iris varieties in our garden are forming flower buds and will begin to bloom in succession continuing the iris season well into June.

Generally, irises are fairly easy to grow, even for beginning gardeners. That holds true only if they are planted in the right spot. If placed in the wrong spot, they will never grow properly and will be a source of aggravation.

Unlike many other plants, irises are planted in July or early August. However now is the time to choose and prepare your iris growing area.

Irises absolutely require over eight hours of full sunlight. If you don’t have a spot that is exposed to that much daylight, it’s probably best not to even attempt to grow them. They’ll never gain enough energy to grow well, much less produce flowers.

The other critical requirement is very well-drained soil. I’ve found that our irises do best in the driest soil we have.  If the spot you’re looking at is moist through much of the year, don’t plant bearded irises there, consider planting blue flag iris that will tolerate moist conditions.

This early yellow iris grew from a piece of rhizome dropped unnoticed along the porch where it receives no direct rain. It is significantly more vigorous than the same plant growing in a moister part of the same garden.

Existing perennial weeds can be a real nightmare to control in any flower garden. If you start preparing your iris bed now, you will have plenty of time to eradicate those weeds for July planting. Trying to prepare a planting bed right at planting time often yields poor results because if you miss any small pieces of perennial weed roots like quackgrass or thistle, they will sprout and grow back with a vengeance.

Be sure to allow plenty of space for your new irises, they don’t do well if they’re crowded by other plants. Crowding can cut down air circulation leading to conditions favorable to plant diseases.

Garden centers get their iris shipments at planting time so don’t look for them yet. Another popular source of iris rhizomes is other gardeners. July and August is also when irise are dug up and divided. This is done every three or four years as new offshoots grow and begin to crowd the plant. As the plants get older, gardeners will divide them to keep them vigorous. Rather than throwing out or composting extra plant rhizomes, most gardeners prefer to give them to someone who will  grow and care for them.

Dwarf varieties like this purple variety are less than a foot tall.

Early in my career, I was given several iris rhizomes that were supposedly descended from Sir Walter Raleigh's garden. Somewhere along the line as I moved, they were left behind. I wish I still had them. They were a nice blue color as I recall, but not particularly notable. They were a great conversation starter however.

Start working on your new iris bed now a little at a time. It’ll be July before you know it and you’ll be in great shape when your iris roots arrive for planting.