Metal trellises: If your plant is heavy and needs a lot of support, a trellis made from metal may be a good solution. Metal trellises tend to cost more than wooden or vinyl trellises, but withstand the elements best and will likely never need replacing. Trellises made from copper tubing will acquire a beautiful natural patina over time. Aluminum is lightweight and very durable, especially when painted. With steel and wrought iron trellises, make sure you look for a rust-proof finish.
Wooden trellises: Trellises made from wood are probably the most popular choice among gardeners. They are inexpensive to buy and if left unpainted, blend in seamlessly with the landscape as they age. If you're handy, there are also plenty of free trellis plans on the Internet, so you might even consider building your own. Wood trellises will eventually succumb to the elements, but you can extend their lifespan by choosing insect and rot-resistant woods like redwood, cypress, and looking trellises fastened together using galvanized nails or screws, not tacked together with staples.
Vinyl trellises: For a low maintenance trellis, one that will never rust and never need painting, try one made from vinyl. Although typically only available in limited colors (usually white, green or brown) vinyl trellises are becoming more popular with gardeners because of their durability. They key is to find out if the vinyl is treated and rated UV stable, meaning the vinyl is resistant to mildew and it won't fade or splinter due to long term exposure to the sun.
Flat trellises (ladders or fences): Flat trellises are usually designed to be anchored to structures like garages, sheds, walls, or fences. A flat trellis consists of a framework in which the slats are connected to form a ladder of squares or rectangles. These trellises come in a variety of heights, and depending on the width, can easily support multiple plants.
Obelisk trellises: With its tall, pyramid shape rising several feet up into the air, this three-dimensional trellis instantly becomes a dramatic focal point of the garden. Obelisk trellises add a vertical design element to your landscape and are meant to be viewed and appreciated from every side. Because their framework consists of 4 sides (usually made from metal), these trellises can support a variety of climbing vines and plants.
Fan trellises: These trellises are made to be freestanding or mounted. They can be used in the same way flat trellises are used, but they are usually designed to support only one plant. Their shape is narrow at the bottom and fans out at the top, which makes them ideal for setting inside of containers and supporting annual vines like sweet peas.