I got new knockout roses in late winter, my zone is middle northwest Florida above Panama City. Having a very wooded lot, finding sun was a problem, so I put them in very large pots that have water drain and saucers, added miracle Grow potting soil to the local soil, known to be poor. Also added a light dosing of Miracle grow (crystals added to water), After a long period of blooming all the time they are now without buds and some small branches are turning yellow. Will they have to be taken out of the pots? After trimming one tree I can now move them from full sun to a north wall that receives good sun and then are protected?
Knockout Roses in Pots
I would recommend moving them from the pots and into the sunny spot. It sounds like they may be becoming root bound in the pots. They could also be staying too wet. Even though a pot has drainage holes, if they sit in a saucer with water in it all the time or for long periods of time, the soils can stay too wet. This wet condition leads to root rot and disease problems in the root zone. Once watered and the saucer has water in it, they should sit in the water for an hour at most. Then the excess water removed. When taken out of the pots to plant in the ground, the root systems may have started growing in the shape of the pots. If this is the case, pull the roots apart a bit so as to try and get them out of that shape. Doing so well help the roots to spread out and grow as they should into the surrounding ground. Use some good bagged planting soils when transplanting them in the ground to help the root systems get going well. I highly recommend watering them in with some water that has both a product called Super Thrive and a root stimulator product mixed into the same water. This will help them deal with transplant shock and help to get the root system growing well into the new soils home. Water them with a freshly mixed batch of this same mix the next 4 to 5 times they are watered. I also recommend finding a good organic or organic based rose food/fertilizer to feed them with. The miracle gro alone does not do enough to build the soils home and keep it healthy. Giving them some Kelp Meal helps both the roses and the soils home doing well.