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I May Be Crazy, But…

Updated: Jul 6, 2021

One goal I have in developing my Fragrant Iris business is to grow iris rhizomes in containers and get them to bloom while in those containers.

I’ve asked a lot of experienced irisarians about my chances for success and have gotten a wide variety of answers. Some assure me that it’s only by rare chance that a “potted” iris will bloom unless the pot is very large.

Others tell me it will take two years before the plants will bloom. That’s too long to try to hold a plant in a small container without it getting seriously root-bound. The plant will become stunted and, once the pot is completely filled with roots, virtually impossible to keep it sufficiently watered.

My plan is, if I can produce intensely fragrant, blooming irises in one-gallon or two-gallon containers, I can then offer those plants, in bloom, through local retail nurseries and garden centers.

I think if people can see the beauty of the iris in bloom plus experience the incredible fragrance first-hand, they won’t be able to resist taking a few home.

I want to make the plants affordable, thus the need for smaller containers. Smaller pot = less soil = lower cost to produce. Plus, anything larger than a two-gallon container becomes a bit heavy and awkward for people to transport home.

Last Fall, as I was searching for online sources for iris rhizomes, I could find only one business that ships bare-root iris rhizomes in Spring. Most everyone in the iris business will harvest rhizomes during their “dormant” period, which is around four weeks after Spring blooming. Typically, the digging time ranges from June to early August, depending on the climate zone.

Old House Gardens specializes in historic irises (those that were introduced more than thirty years ago). They ship irises in both Spring and Fall. So, I ordered three rhizomes each of three different varieties for delivery this Spring.

Those arrived yesterday. I soaked them for several hours in rainwater with Miracle Grow fertilizer.

Today I planted them in containers. I’m experimenting with three different containers, a one-gallon RootMaker® air-root-pruning container, a two-gallon smooth-sided (traditional) container and a two-gallon RootMaker® air-root-pruning container.

This photo shows the one-gallon RootMaker® on the right, the two-gallon RootMaker® on the left and the two-gallon smooth-sided in the middle.

Here’s another photo looking down into the containers. The RootMaker® containers are pretty obvious due to the holes for air-root-pruning in the side walls.

When planting iris rhizomes in the ground you want to dig a hole and create a mound in the center of the hole. The rhizome sits on top of the mound with the roots straddling the mound and directed down into the hole on either side.

In the photos below you can see that I’ve used that planting technique in these pots.

When your’re finished filling in soil around the roots the rhizome should sit right on top of the soil or with just about half the rhizome covered. The main concern is not to plant the rhizome too deep.

For this experiment I’m growing three varieties, Iris germanica, Iris flavescens and Iris Caprice.

I. germanica and I. flavescens are both considered to be species, although some consider I. flavescens to be a natural hybrid dating back to 1813. Caprice is a historic iris that was bred by Vilmorin in France and introduced in 1893.

So, I have three varieties with one of each planted in a one-gallon RootMaker® container, one of each planted in a two-gallon RootMaker® and one of each planted in a traditional, smooth-sided container.

I know from past experience that plants grown in air-root-pruning containers will grow at an accelerated rate. That’s what I’m hoping will allow me to produce blooming, container-grown irises in one season. I’m growing the same varieties in a two-gallon traditional container as a “control” so I can see if there is a noticable difference in the plants’ growth rates.

I’ll grow these this year to see if any of them will bloom this season. I realize it’s a long shot but I figure if I don’t test I won’t know.

Success or failure, I’ll keep you updated as this experiment progresses.

And maybe one day I’ll bring intensely fragrant, blooming irises, in containers, to a nursery or garden center near you!

Randy Smith

RootMaker® is a registered trademark of Lacebark, Inc. an Oklahoma corporation.

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2 comentários

19 de jan.

Hi Randy, could you please provide some updates on how your experiment turned out?


Randy ~ Iris WILL bloom in two gallon, conventional smooth sided containers within a year of planting with some luck. I purchased potted rhizomes from our local iris society late summer / early fall in 2020 and most of them bloomed in 2021.

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