Guidance regarding perennials in pots/planters...

Those are hardy perennials and should easily overwinter right in the container left outdoors in a sheltered location if possible (to avoid too much snow mounding on the container--not for the plants but for the safety of the pot!)

Anything in a container is going to need feeding but these are not fussy plants. Feed in spring after last frost, after first flush of blooms, and once more in mid-summer. It's always a good idea to top dress with an inch or two of compost periodically through the season so you're feeding the soil as much as the plants.

You're plants will be fine in the soil (as long as you topdress with compost as noted above) for several years but at some point you'll need see the soil level going down. That will likely be right about the same time you need to divide these perennials (3 years probably) at which time you'll unpot, divide and replant.

It's a nice collection. I've grown chocolate cosmos for years and years...!

You may have to bring them into a slightly heated area like a garage or a basement. Do not leave them outdoors in the pot over the winter, the soil will freeze and the plants will die most likely.Water them deeply monthly over the winter months until its safe to put them outdoors again. Always check for any insects or diseases that can hitchhike inside from the leaves or soil if left outdoors during the growing season.

Re: soil changing, you can change it but you would be disturbing the roots the plants are trying to put into that soil (some of those feeder roots might break off during transplanting).

Generally if you have annuals in a pot, you remove the soil after they die, and using a 1 part bleach to 9 parts water, clean the interior of the pot to get rid of the salts collected on the sides from the fertilizers and it also kills any fungal spores. I would use fresh soil (container mix type bags) for annuals.

Perennials can stand a little of the ground soil, but if they are really a small sized perennial that will eventually get larger, I would use the sterile container mixes instead. Sometimes fungi in the soil can overwhelm a seedling or a very small plant and it could die.

See, always differing opinions. I leave my perennials in pots overwinter in the Northeast and they come back every season!

On 4/4/2014 gardensla said:

See, always differing opinions. I leave my perennials in pots overwinter in the Northeast and they come back every season!

I would 'heel' them into the ground, pot and all.

On 4/4/2014 JustJazzmom said:

On 4/4/2014 gardensla said:

See, always differing opinions. I leave my perennials in pots overwinter in the Northeast and they come back every season!

I would 'heel' them into the ground, pot and all.

A good idea, for sure

On 4/4/2014 JustJazzmom said:

On 4/4/2014 gardensla said:

See, always differing opinions. I leave my perennials in pots overwinter in the Northeast and they come back every season!

I would 'heel' them into the ground, pot and all.

Exactly what I was going to suggest. It's the safest way to carry perennials over in pots.

Thank you so much gardensla, JustJazzmom and gardenman for the incredible responses! So much terrific information! (I posted a similar question on Roberta's fb page but cannot imagine a reply with so much information anywhere else but here!!! )

I so appreciate your taking the time to share your knowledge and experiences!

As mentioned, I have never attempted to winter over potted plants. (I have only planted annuals or Dahlias - I remove the bulbs for storage with those - in the many, many pots we have...I was concerned about the roots surviving in pots and continued nourishment.)

I was not familiar with heeling plants in...and have now done some research. Could I ask those who do heel plants into the ground how you do so? Looks like some do so in the pots, while many prefer to remove the plants from the pots for heeling.

I learn so much here...again, thank you everyone for so much help!!!

Usually 'heeling' is done with you planting the pot with the plant inside it. Then when the weather warms up, you remove it from the soil and take care of it like any other containerized plant.

The heeling keeps the plant warm through the winter and you don't have to worry about watering it due to the snow or rainfall. If you had left the plant in the pot outdoors w/o heeling, the air surrounding the pot would dry the soil out faster than it would dry if the pot was buried into some soil.

And to follow up on what JustJazzmom said, you don't even have to use soil to heel the plant in. You can fill the hole with mulch rather than soil and that will make the plant less likely to grow out through the drainage holes to get into the soil. Some aggressive growers will send out roots right through the drainage holes and take root in the soil making it a real challenge to lift the pot in the spring if it's in soil. Even though the top of the plant may appear dormant, the roots are often still pretty active. Instead of just lifting out the pot, you can find yourself in a real tug of war with a plant that's firmly rooted itself into the subsoil. A thick layer of mulch under the pot tends to minimize that risk. Mulch isn't quite as effective as soil in protecting the plant, but it does make removing the plant in the spring much, much easier.