Often times we think plants for our outdoor gardens need to be planted in soil. But I'm here to say: Ditch the dirt! There are some wonderful options that just simply require a container of water, such as Pistia Stratiotes, more commonly known as water lettuce. This is not a lettuce that you would eat, but instead a water plant that adds a little diversity to your outdoor plantings. Usually found in Florida, water lettuce can actually cause havoc on local streams and rivers in mass quantities as it latches together to form a thick mat, preventing boats from passing through. Although, in controlled smaller spaces, it's an intriguing specimen that most are unfamiliar with. Water lettuce might look like typical lettuce leaves, but upon closer inspection they have no stalk and the leaves have a fuzzy low pile on their surface that you kind of want to pet. Most visually intriguing about the water lettuce is its fine feathery roots and offshoot "pups" that it grows, creating a network of pond buddies.
Flickr photo by udariza
Water lettuce is tolerant of part shade but prefers full sun to look its best. If you purchase very young plants, acclimate them to the full sun so that their younger leaves do not get bleached out. They are easy to water since you can visually inspect when water is low without having to guess. Water lettuce is a perennial that will only tolerate temperatures down to 59 degrees Fahrenheit, so enjoy it while you can. They can be used in conjunction with fish, just make sure that there is plenty of exposed water surface as they block much of the air supply that the fish require. Prune off any yellowing leaves to keep them in top shape but be gentle as to not damage the root system.
These funny floating plants are perfect to spruce up an outdoor space and add that hint of something special that will set you apart from all the other decks on your block. If you do not have a big enough space to have a built-in pond, try them in a larger clear container so that your guests can ogle over the intricate root structure. Take a look for them at your local garden center, or you can even find them online ready to ship to your doorstep. Sometimes you just have to think outside the box, or in this case bag (of potting mix), and try a water plant to mix things up.