Hello, this is the first winter that I have tried overwintering iris in pots. I am hoping for the best. So far we have had a fairly mild winter for zone 6. My first question is about fertilizing? When and how much. Thank you!

Hi Teresa. I have some in pots too. I don't usually fertilize them over the winter. If they were planted in a potting mix, or fertilized when potted then they should have plenty of nutrients.

About a month before bloom time is when they recommend you fertilize the planted iris. You could give the pots some at this time too. Just be careful to not get the fertilizer on the rhizome. Mix it gently in around the outer edges of the pot perhaps. I would go with a light application.

Hopefully others will also chime in with some advice.

Thanks Leslie, I was wondering about how close before bloom time. Not now. I have been using Osmocote on my garden plants, so I plan to use that. Does a tablespoon sound like to much for a gallon pot?

I just started using my Scott's superbloom again on all the pots. It can touch foliage and rhizomes since it's water saluable. I'll apply it once a week to already moist soil.

Otherwise as Leslie stated about a month before blooms, which is a tough guess these days. Just make sure to scratch it lightly into the soil, and water good. Depending on your pot drainage, 1tbsp and no more per pot. It does take time to break down, but you'll notice results really fast. Especially since they're waking up soon.

Thanks, Gabe. Looking forward to seeing some new blooms.

@bluegrassmom
Teresa,

I looked up osmacote and its numbers are 19-6-12, not the optimum ratio for iris. Maybe someone else can comment who knows more than I do.

The 19 is high, and may be too much Nitrogen for a contained space like a pot. You can pick up some bulb food, like Sta-Green that is 4-10-10, or even Miracle Gro Shake N Feed for Roses (make sure it is the Rose formula) which is 9-18-9. Either of these can be used in the gardens as well.

I am wondering if you have irises that have been in pots that have formed a good root system, can you plant them in the ground now in Spring or will that mess them up or keep them from blooming? (Like they would bloom in a pot anyway?)

They can be planted, but I would wait until there is no threat of prolonged freeze so the iris doesn't have stress while trying to establish itself. It may delay bloom, but I think that will vary by plant.

I had many iris bloom in pots last year! They did great.

I had a more than few bloom last year when I made my first raised bed last March possibly.

Thanks, Leslie for mentioning the ratios