The beautiful bottlebrush is a woody, upright shrub that can be grown into a small, weeping tree about 20 feet tall. Callistemon sports bright-red bottlebrush-shaped blooms that are attractive to hummingbirds and bumblebees. Very young specimens have pale green, soft and fuzzy leaves, but they'll outgrow that. The foliage of mature trees is shiny, darker green and stiff. This fast-growing Australian native is winter hardy in North American Zones 9 to 11. The bottlebrush can withstand short cold periods that don't drop below freezing, or even very light frost as long as it's kept fairly dry.
Plant your bottlebrush in a very well-draining, moderately rich soil in full sun from late spring through midsummer. These plants love warmth, humidity and sandy soils and thrive best with either neutral pH or a slightly acidic environment.
Apply a 2- to 4-inch layer of organic compost to the bottlebrush's planting site each spring. This will not only help to retain moisture, but it will significantly reduce problems with weeds.
Water the bottlebrush plant deeply spring through fall. Keeping the soil evenly moist, but never soggy or wet. Mist the foliage every week with lime-free water throughout the growing season if humidity levels are low. Lime will stain the leaves. Let the plant dry out completely between waterings during the winter months.
Feed your bottlebrush a monthly application of good all-purpose liquid fertilizer throughout the growing season.
Clip the stems right behind the blooms as they are spent throughout the growing season. This is all the pruning that bottlebrush really requires. Stop clippings during the fall so that you don't encourage any more new growth, which could sustain heavy damage during subsequent winter frosts or cold snaps.
Shape the young tree gently with light tip prunings of new growth very early in the spring while it's becoming well established, if you feel that you must. Know that you might be sacrificing some blooms by doing this. But it's much healthier for the plant than attempting extensive radical pruning when it matures, which will cause the bottlebrush to be very unattractive for quite some time.