If these were one or two gallon size plants, chances are they were simply too immature to set buds last summer/fall. Even for larger sizes, it's quite common to not have any bud set in the first year after planting out. Given your experience with the root balls, it is probably worthwhile to dig up one or two to see what shape they are in even if this has little or nothing to do with the lack of bud set. Seriously matted root balls need more than a bit of prying with a shovel. You need to eliminate circling roots at the edges and bottom. This may mean cutting with a sharp knife, using a hand cultivator as a claw and/or a forceful stream of water from a hose to expose1-2 inches of the root ends. You'll lose some roots and think you're committing rhododendron murder, but it's the only long term cure. Once that's done, water by immersing in a bucket for the ones you dug and letting a hose trickle at the base of the plant for a half hour or so each time they need water for the rest and after replanting. A sprinkler hose will not wet a dry peat-based root ball. You want to wet the root ball, not the surrounding soil. Saturated soil makes it more difficult for the roots to extend out from the existing ones. You may have to water like this for a second year as well.

Yes, Prince Charles will reach 12 feet ++ at maturity. This is a wonderful clematis, provided it is planted well for years of pleasure. I mix in lots of manure, compost and bone meal at planting time and I dig a very large and deep hole for the huge root system which will develop within a few years. Perle d' Azure is a weaker clematis, in my opinion. There are some that do very well after a long time to establish and others which do very poorly, but Prince Charles does well much more quickly and the flowers are also quite beautiful. It is a vigorous and lovely clematis. I prefer Prince Charles. Suzy

Update with a pic to come in a little while. I had to give mine a bit of a trim. One of the habits of the plant is that some branches will just start dying off. The leaves will start drying up, and leave the bare branch behind. I noticed this on both of the plants I had last year. I was worried it was some type of a disease. One of the master gardeners came by. After checking things for a bit he came to the conclusion that it is just something the plant does. It does it the most as the temps start to climb over 85 during the day. Though by the time the it became much of an issue here I had already harvested two bushels of tomatoes off of each plant. I then took a few good cuttings, and rooted them. I kept them in a shaded area until the heat wave broke. I planted them out again, and got a few more before the first frost. For me since they were so prolific, and early I am planting one again this year. I will do the same again next year. I just know to pull the plant when I get the last of the ripe fruit off of it. Pics to follow here in a while. Nate. Seysonn I am supporting it with one of the 4 ring cages. For my purposes it will work out just fine. By the time the plant outgrows the cage I will be pulling it anyway. I think the cage is 52 inch or so. I got a few of them for free when helping my wife clean up a rental property for the owner, to get it ready for the new lease holders to move into. A closer look at the fruit. The larger ones are the size of baseballs.

Jayvee That is very nice set-up for your plants! Back to 'Black Prince': *It is potted little too low in the pot - there is lots of space between top level of the soil and top of the pot, plant is sitting too much inside. While not a huge problem, this decreases air circulation slightly, especially in hot and perhaps more humid climate. Every little thing adds up... *There is no need for such large pot. It holds too much soil, and if it's not so well draining - too much moisture for too long. *New plants should be acclimatized to good sunlight - usually, it is difficult to know where was plant before the purchase. Most succulents like full sun, but from the color of your plant (quite a bit of green in the center) it looks like it spent some time just prior to you buying it in lower light (this plant is typically have dark color thru-out). It is best to put plant in semi-shade for few days, moving it into more and more sunlight gradually (every 3-5 days or so). *Well-draining potting mix and drainage holes in container are important - plant could be watered well when needed, and extra water will drain. Whatever sits in saucer about 20-30 min after thorough watering should be disposed off. Rina