Unusual containers for your plants can be a lot of fun and add unexpected pleasure or whimsy to your garden displays. If the container is not entirely suitable (an odd shape, or not conducive to providing good drainage), simply nest a plastic pot inside it and let developing plants hide the actual container from view over time.
Check out these options:
Hanging baskets: With a hanging basket, always make sure that you've accounted for drainage and that the resulting display is adequately supported by wires, chain, string, rope, or what have you, because a full hanging basket can be quite heavy. If taking the display down to water it is a hassle, try using a watering wand. Some possibilities include plastic, clay, wood, and coconut- or moss-lined wire rigs.
Wall containers: A wall garden is a clever and often quite charming way to display container-grown plants. You fasten them to a fence, courtyard wall, or other vertical surface (or a trellis against one), preferably at eye level so you can readily appreciate them.
Many containers intended for this use have one flat side so they can go flush against the wall (these containers are sometimes called a half pot); though this feature isn't a requirement, it does look better and allow the plants within to grow upright. Obviously, the supporting wire, brackets, or hooks have to be equal to the job, and that means holding the weight of a filled container. Although you can rig something yourself, well-stocked garden-supply stores often have a nice selection of these containers, and they come with whatever support is necessary.
Old shoes and boots, tea kettles, wicker baskets, cookie tins, old tires, wagons and wheelbarrows, and more: You can recycle all sorts of wacky and whimsical objects to hold and display potted plants — just use your imagination! Browse garage sales, thrift shops, junk piles, or even your own garage, basement, or attic. Any vessel of weather-resistant material can be a candidate. Containers that at one time held toxic chemicals like oil barrels should be avoided, also those constructed of wood products that contained harmful preservatives, like creosote.
Oddball choices work best when the plants within don't overwhelm them or spill over the sides and hide them from view, so choose smaller plants or ones that are slow-growing. Also, refer to the caution about attending to drainage.
Whiskey barrels are pretty standard at garden centers and home supply centers, along with plastic look-a-likes. The word whiskey comes from a Gaelic phrase for "water of life," and plants can certainly live a happy, well-watered life in a (whiskey-free) whiskey barrel. Half whiskey barrels are a popular choice for planting many or larger plants, including small trees or even waterlilies and other aquatics in a plastic-lined miniature pond.
Line a barrel with plastic or use a plastic insert made for this purpose before planting; you want to prevent the rot and loosening stays and slats over time and also to protect the soil and thus plants from absorbing any leached tar or creosote that may be lingering. And don't forget that one of these barrels filled with anything is mighty heavy, so move it to its intended site before you fill it.