I like to start with a center focal point plant and two or three other plants in a 14 inch pot. Plants that I use for a center focal point are the dwarf cypress papyrus, a red cordyline australis ‘red star’, a striped phormium, lemon grass, a bamboo or even a black- stemmed sugar cane.
Here's a mixed container that I just started this past weekend. It has a dwarf Papayrus, aStrobilanthes, a Pelargonium and a variegated bougainvillea in the back.
An article in Fine Gardenin magazine a couple of years ago referred to the assembly of mixed containers as the Thriller, the Filler and the Spiller. Keep this in mind when you are assembling your mixed containers.
The Thrillers are the centerpiece plant. The Filler plants are some of my favorite accent plants. These are usually upright growers with lots of color or form. You can use short growing coleus,Nemesias. Begonia ‘Christmas Candy’, Angelonias, Heliotropes. I use Heliotropium aborescense alba. I love this white flower filler because of its vanilla scent. Heliotropium arborescense 'Iowa', a purple blooming plant with a slight wine-scent is another good choice.
Abutilons are also great plants to use, such as our Abutilon ‘Kristen’s Pink’ has wide open bells.
Our Summer Breeze collection is one of my favorites.
Finally, the Spillers or trailing plants can be plants such as Ipomeas. There are chartreuse green ones, black ones or even variegated ipomoeas that trail. I used Pink Frosted in my container that will bring out the colors in the other Pelargoniums balcon royale are good choices. Another great trailer is scaevola or fan flower or Plumbago auriculata 'Imperial Blue'.
Try two mixed containers of the same plants and balance a walkway or front entrance to make a dramatic effect! Like this Guardian Gate collection which boasts Cypress Papyrus, Begonia Christmas Candy and Scaevola