Plants don't care what holds their soil as long as it doesn't leave their roots soggy and water logged. Make sure whatever you use for a plant pot has drainage holes. If it doesn't, plant the flower or bush in a pot with drainage holes, remove it for watering and replace it in the decorative container when the water has drained out of the flower pot.
In a rustic garden an old bicycle leaning on its kick stand with its basket filled with flowers looks like its waiting for its rider to return. Line the basket with coconut fiber and potting soil and then plant with flowers. Gerbera daisies are cheery and informal. Geraniums are old fashioned. Petunias look sweet. A few trailing flowers soften the edges. A child's wagon filled with spring bulbs is easy to put together. Buy the bulbs already blooming or use pots you've planted up the previous fall. Put a 2 inch layer of gravel in the bottom of the wagon. Pack the pots closely together. Cover the tops of the pots and the spaces in between with sphagnum moss.
Mad Hatter's Tea Party
Create a mad hatter's tea party. Fill old tea pots and cups with succulents. In the bottom of the pieces of china put 1 inch of activated charcoal, the kind used for aquarium filters, and then a 2-inch layer of gravel. Plant the succulent in cactus potting soil. Water very sparingly. Tip the china to drain as much water out as possible.
Find old metal watering cans. If the bottoms are a bit rusty and leak, so much the better. Punch drainage holes in the bottom of the cans. Fill with potting soil and plants. Thread a few vines through the pouring spouts. Spray-paint new watering cans. Punch holes for drainage and plant. Line the watering cans up on a shelf, on top of a fence against a wall or all in a flower bed.