Question
I have two small (4'-5') double purple Althea trees that I would like to plant in huge tree vase pots; see exact pot at home depot link(http://www.homedepot.com/Outdoors-Garden-Center-Planters-Planter-Accessories/h_d...) This pot practically swallows the tree completely. It will have 2-3' of soil on bottom and top of rot ball and approximately 1' of soil on sides of root ball.  Is this pot big enough to to protect root health from freezing and sustain life over the winter outside in northern IL(Stephenson county)/southern WI (Walworth county)? I know in-ground is best and really no wintering needed then, however I had a beautiful, abundant, 3yr-old double purple althea that was in ground and I uprooted to relocate to IL and it did not survive the move. I was heartbroken. I want to avoid the trauma and loss of possible uprooting by simply potting this time. 1 Thank you for your help

Answer
Hi Theresa,
Thanx for your question.  The pots would be fine but remember, they still have to be shielded from the cold north wind, especially where you are in the north central states.  If we're talking about Hibiscus syriacus (called Althea and Rose-of-Sharon), this is a hardy shrub or tree, hardy to Zone 5.  It's a pretty tough plant.  Like I said, the pots are fine but they still need to be sheltered from direct contact with the cold north wind.  Put them behind a wall or in an unheated shed in the winter or place them in an area that is sheltered from the cold north wind.  I hope this helps.
Tom