Yes, you will need to repot. How often depends on the size of the pot, the planting media used and what's growing in it.

Potting soils deteriorate over time. They collapse and compress, impacting both drainage and aeration. So they need to be replaced periodically. The less textural and durable the potting mix - something like Miracle Gro - the more frequently this will need to be addressed.

Plants will become rootbound in a container, some a lot faster than others, and this is complicated further if you have multiple plants in the same container. If left untended, this can create issues with growth and productivity. So they will need to be unpotted and the root issues addressed, either via root pruning or by up-potting. And of course the size of the container will have a bearing on this as well.

I use a very high quality, durable, custom potting mix that holds up well and tend to use pretty generously sized containers as well. My mixed perennial containers get repotted every 2 to 3 years and often recreated at the same time with the larger, older plants recycled into the garden. With trees and shrubs, the process is every 3-5 years.

The routine fertilization of containerized plants is a given regardless of the need for repotting.

And to minimize the 'intrusion' might it would be best to repot as early as possible in the season? (Oh and thanks for the reply gg).

It depend on how much root manipulation is necessary. I try to time the need for any root pruning to coincide with dormancy or before active growth. But otherwise I repot whenever I have the time and inclination.....and recognize the plants are crying for attention!! I do try to avoid the heat of summer, however.

media is a water management system within the pot ...

when you can no longer properly water the pot ... because the media is filing.. its definitely time to repot ...

the whole plant may sink ... due to the deterioration mentioned above ... water might not easily flow thru all the media... so it might be sodden on the edges and bone dry in the center ... which might also be a function of the root mass getting to large in a small pot ...

with small pots.. you can just slide the gob out.. and look at it ... of course when you start getting into huge pots.. that wont work ...

i would prefer a sterile media ... and add what was needed with water sol fert .. rather than starting with a media that already has fert in it ...

imo.. your equating the fert with whether or not the media is viable ... is not addressing the water management side of the issue ... you cant manipulate fert to overcome a failure of proper watering ....

ken

Yup. I will repot a few this spring. Thanks for the expertise.

The less textural and durable the potting mix - something like Miracle Gro - the more frequently this will need to be addressed.

I am sure some of you make your own proprietary potting mix. The difficulty in posting the recipe is terminology ie what something may be called in your area may be different in my locale. In any event I would love to see your recipe.

I overwinter various excess perennials potted (or repotted from what they came in) with our garden soil but only for use the next spring.

For my purposes, I really take Gardengal's comments to include a general reminder not to buy root-bound perennials in garden centres. These may be available, and at sale prices, in spring.

If they survived the winter in pots you will tell in May and re pot then. The best thing for them is to be in the ground, unless that isn't an option.

Any perennials I pot for (multiple) overwintering have come from our garden so root bound for sure isn't an issue....at least initially.

'Matt', we really like having the flexibility of having potted perennials (and annuals). They are an important component of our overall garden.