Native to Australia, a bottle brush shrub, also known as Callistemon, have large thick cylindrical blooms that look like bottle brushes, hence their name. They attract both butterflies and hummingbirds and are lovely accents for the home garden or landscape and when planted in rows, make an attractive border or hedge. Bottle brush shrubs are commonly grown in the south and can tolerate some mild freezing temperatures, but if temperatures dip below 20 degrees F, an entire bush can be wiped out. A bottle bush shrub requires well-draining soil and place in the sun to grow well.
Determine which plant hardiness zone you reside in. Visit the National Gardening Association or Arbor Day Foundation websites and search for your USDA zone using the zip code search function (see Resources). If you live in USDA zones 8 to 11, you can grow most bottle brush shrubs outdoors in your garden. In cooler zones, dwarf varieties can be kept in a container and brought indoors once temperatures dip below 45 degrees F.
Decide which kind of bottle brush shrub to buy. For example, the stiff bottle brush variety (Callistemon rigidus) will tolerate colder temperatures, so if you live in zone 8, this may be a good choice for your landscape. Growing only 5 feet high and 8 feet wide, the narrow-leaved bottle brush variety (Callistemon linearis) may fill in nicely to create a lush hedge or border. If you want a taller variety, the crimson or lemon bottle brush (Callistemon citrinus) grows 10 to 15 feet in both height and width, but the Little John dwarf cultivar of this same variety makes a good container plant. The prickly bottle brush (Callistemon brachyandrus) tolerates hot, dry conditions, making this a suitable choice for hotter climates, such as in zone 11.
Purchase bottle brush shrubs at a local nursery. Choose shrubs that have green leaves, do not appear to be diseased or damage, and just overall, look healthy. If you live in a cooler climate where bottle brush shrubs are not sold locally, purchase them through a reputable online or catalog nursery. Buy enough bottle brush shrubs to fill in your space, which differs among varieties and based on their mature width.