Inland Northwest, High Desert
Give an Inch, Give a Foot
Seen those cute pot feet? They're often in the form of animal toes of one sort or another and they are essential for larger containers. Pot feet set a planter up an inch or so from the deck, allowing water to drain easily. That's important for preventing root rot. And the pot feet set the planter up high enough to encourage air circulation and prevent water rings on the deck, as well.
Leave No Air Pockets
Roots need air. When water drains properly through the planting medium, roots have access to oxygen. Air pockets are quite another thing. Make sure you don't leave empty pockets between the cuttings. Poke around with your fingers to make sure you feel potting soil protecting all sides of every cutting. Otherwise, your baby plants will dry out and die in no time.
Choose Something Radical
Planting in containers is like flower arranging outside. In a good arrangement you need height. Dracena has been popular the last couple of years. How about something with more oomph? A baby pine tree? Or an 'Emerald Green' arborvitae? Or a tree rose? Maybe a small pyramidal trellis or a cute tomato cage for sweet peas to climb? Think up, and use your imagination.
Create Layers in Containers
Lightweight plant stands are usually designed to hold three potted plants in a decorative tower. You can place one in a large container and put trailing plants in pots on the middle layer, something upright on top, then fill in around the base with more trailing plants. Euonymous works great on the bottom.
Be a Big Drip
Drip systems for containers, even a series of hanging planters, are available as kits in some hardware stores. They'll mind your beautiful flowers with less water, even while you're on vacation.