Bottlebrush shrub, also known as Callistemon, is a subtropical plant native to Australia and is easy to grow in warm climates with mild winters. The fine, strappy foliage is evergreen, and bright flowers bloom at the stem ends, giving them a pipe cleaner look. Pollinators of all types flock to Callistemon during its long flowering period from mid to late summer. Several forms of Callistemon are available, ranging from upright, 15-foot shrubs to ground-hugging, dwarf varieties that are suitable for container gardens.
Photo by K M, unmodified, Flickr, copyright CC BY 2.0 DEED
This shrub requires moist, but well-draining soil and full sun exposure. Bottlebrush is hardy in USDA zones 8b-11; however, gardeners in colder climates can grow it as a houseplant over the winter. Bring the container indoors to a sunny location, or use a dedicated LED grow light through the darkest months of the winter.
Shrubs To Plant With Bottlebrush
Bottlebrush pairs effortlessly with other subtropical shrubs to create a low-maintenance garden border or informal hedge. For long blooming periods, select from Australian tea tree, grevillea, Coast rosemary, and Natal plum. All of these shrubs require little pruning and fertilizing. Other Mediterranean plants like rosemary, thyme, lavender, and junipers look nice with bottlebrush in a dry garden or waterwise design.
Perennials To Plant With Bottlebrush
Bottlebrush flowers attract beneficial pollinators in droves, especially hummingbirds. Use bottlebrush to anchor an area dedicated to colorful pollinator plants, like lantana, aloe, sedum, kangaroo paw, and golden sage. You can also include hardy perennials such as allium, coneflower, blue fescue, and yarrow, which all flower prolifically for weeks at a time. Several groundcovers grow well with Bottlebrush, including creeping thyme, ajuga, pachysandra, liriope, and catmint. Use the groundcovers to form a dense, weed-proof barrier that additionally attracts pollinators when in bloom.
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Annuals To Plant With Bottlebrush
Planting annuals around bottlebrush shrubs is a great way to create a specific mood. Long-flowering bedding plants like cosmos, cleome, snapdragons, and California poppies are prolific self-seeders and can fill in a space quickly. They provide a naturalistic, informal feel. Late-season tropical plants typically sold as annuals like canna lilies, large-flowered hibiscus, mandevilla, tradescantia, and purple fountain grass provide rich saturated color that lasts well into the autumn. Use these colorful plants to set a tropical tone in the garden.
Best Companion Plants For Bottlebrush in Containers
Smaller Bottlebrush varieties are ideal for smaller garden spaces and containers. Include smaller rooted filler and spiller plants if the planter is large enough. For contrast, use trailing bacopa, calibrachoa, sweet potato vine, or creeping zinnias with bottlebrush. These annuals additionally have a long bloom season and attract pollinators.
The containers can be moved to a frost-free location through the winter months. Choose a container that is at least 2 inches larger than the rootball to grow the shrub as a single specimen.
Photo by K M, unmodified, Flickr, copyright CC BY 2.0 DEED
Plants Not To Grow With Bottlebrush
Bottlebrush shrubs require 6 hours of direct sun to bloom well. Plants that prefer part to full shade are not suitable companions and may show signs of sun scald next to bottlebrush. Leave most ferns, large-leaf hostas, rodgersia, and trilliums in their woodland setting where they are best suited.
Best Plants To Grow With Bottlebrush
Ultimately the best companions to grow with Bottlebrush shrubs are perennials and shrubs that thrive in full sun with well-draining but moisture-retentive soil. Many subtropical plants have similar growing requirements and offer showy flowers and foliage. Plant bottlebrush with viper’s bugloss (Echium ssp.), angel’s trumpet, eucalyptus, and clumping bamboo for a spectacular, low-maintenance design in USDA zones 9-11.
Sources: “Lemon Bottlebrush Garden.” Waterwise Garden Planner. waterwisegardenplanner.org