Thanks, all, for your contributions to an interesting discussion.
I still maintain that Knockouts do well in pots. They do stay a smaller size than when planted in the ground. Our Iowa garden is in Zone 5, so roses in general don't get as tall as they do in warmer zones. Since my audience consisted of Zone 5 gardeners and since the rose will stay a smaller size when potted, ungainly size was not an issue in my presentation.
In my experience, Japanese beetles are not fussy about what species or cultivar the rose is. Actually, I had fewer beetles on the Knockouts last summer than I did on my other roses.
Rick, I'm puzzled about your comment that Knockout blooms don't look like roses to you. Could you please elaborate?
Renée, if you want to keep your rose potted over winter, it's best to bring it inside or at least move it to a sheltered area. Pots are subject to windchill, which can damage the rose's roots.
Woofie, the size of the pot will depend on the size of the rose. If the rose is about two feet tall when you buy it, a 12" pot would be ideal. Depending on how fast the rose grows, you may want to plant it in a slightly bigger pot the next year or, as has been suggested, prune your rose (in early spring) to keep it in bounds. If you use a potting medium the first year that has timed release fertilizer in it, there's no need to feed it that season. The second year and in succeeding years, a general timed release fertilizer is best.
Thanks Vicki and Sue, for your kind comments.
Monica, thanks for the root pruning suggestion. You're right, many gardeners tend not to think of pruning the roots.
Thanks for your kind comments, Shoe, and for the Drift series suggestion.
Yes, alas, Knockouts have no fragrance, as is the case with many hybridized plants these days. One of the reasons I included alyssum in the planting was that it imparted fragrance to the arrangement.
