Question
Every year I try to plant several large containers with plants like the ones I see at the nurseries in my area; but, I don't have the sme luck with them.  This year I saw an arrangement that contained Ipomoea Sweet Caroline Purple, Sun Chimes Lavender Diascia x Hybrid, and Laguna White Lobelia Hybrid.  I started out with a whiskey barrel and planted two (2) of the ipomoea in the middle and one of each of the other plants on the right and on the left.  In total, there are 6 plants in the barrel.  The ipomoea are getting very, very big (bigger than the 6 - 8" on the info stick) and are towering over the other four plants causing them to not grow very well and they are starting to die off.  Can I stop this process now?

In the nursery, the container with these plants looked fantastic.  With mine, both the lobelia and diascia are very, very small and they have not lived up to the info on their plant stick.  Please help.  What am I doing wrong?

Are there any general rules of thumb when planting container gardens?  I seem to have the above problem very often.  How come they look so fantastic at the nursery; but, I don't get the same results at home.  Thanks for your help.

Answer
The question I will try to answer is, "why don't my containers look like the nursery container?"
I will start by saying that Ipomoea is "morning glory vine". It may only reach 6-8" high like the stick says, but it will get 15 to 30 FEET long. That is enough for many whiskey barrels. It is a runner. Moving along the ground, and when it blooms it seeds itself every where.
To keep this plant looking the way it does in the nursery, I would guess that they are pruning it constantly to keep it the size they want. (It would be nice if you could talk to the person planting, and caring for the containers you like, and find out just how they do it.) But I will try to figure it out. The smaller plants that aren't doing well, sound like a case of too much dirt. I hear you saying, what does she mean, too much dirt?  If you ever look at a nicely planted container, you will almost always see that it is jammed with plants. It may look too crowded to do well, but there is a reason for the jamming that has nothing to do with the way it looks. When there are only a few plants in a large container, and lots of empty dirt, the water is wicked away from the plants, and they wilt and die. Having little space for the water to go, means that the water stays on the plants and they stay wet. There should be some dirt between the plants so that they aren't touching, but learning to judge how much room they need is an important part of the creation. I am guessing that you are using a standard whiskey barrel, and you have only planted 6 plants in it.
Here are some ideas you might try with your whiskey barrel.
Pick plants with a long bloom time. Annuals are the best.
Pick a tall focal plant for the center, medium filler plants for the middle around the tall plant, and draping plants for the outside edge all the way around.
If it is against a wall, then you can do a half circle, with the tall plant in the back- middle. Fill it with color and texture. Knowing how to use the colors is as important to the design, as knowing the plants. Knowing both is what makes the best containers. Perhaps trying to copy the nursery planting, without know what technic they use to get the results, is where you are going wrong.
How do you stop the process? Put the morning glory vine in a hanging basket. Then go shopping. Use the process I talked about to pick your plants. Buy three or four of the same plants to give the creation unity. White is good to give the colors a contrast. Have a theme in mind. Remember a whiskey barrel is "rustic".  So that could be your theme. The lobelia is a great plant to soften the ruff edges. Alyssum is another. But the best for color on the edge are Million bells. Find a place to set your plants in the store, so that you can visualize what they will look like together, and how much room they will need. You may need to put some plants back, I always do. It sounds like you are very good at reading the lables, and looking for the size. That is very important. Now get creative. It really can be alot of fun.

bakerplanter