Blood red blooms cover the top of this dwarf evergreen plant for an extended season. Dense branches are covered with blue-green leaves. The versatile dwarf size is perfect for today's smaller gardens. The ones pictured below are known by their scientific name, Callistemon Citrinus, or "Little John".
The common name, "bottlebrush", perfectly describes this plant's bright red flower spikes. Hummingbirds love the flowers, and this plant is hardier than most other bottlebrushes. The flowers are followed by small, woody capsules that look like bead bracelets on the bark and which last for years. Although normally offered as a shrub, bottlebrush can be trained as a tree to 15 feet. It makes a nice screen or tall unclipped hedge. Pruning to develop several trunks and removing some lower branches can create a fine small specimen tree. However, the average size of "Little John" is only 3 ft. tall by 5 feet wide.
The leaf arrangement is alternate, the leaf color is blue-green, and the leaf blade length is from 2 to 4 inches. There is no fall color change. Flower color is red, and they are quite showy in the spring and summer. Each bottlebrush-shaped spike is composed of many separate flowers. The pollen is contained on the end of the long filament. The seeds are contained inside a small fruit that forms on the stem. The fruits tend to stay on the tree for one or more years before they release the seeds. If you want to grow the bottlebrush from seed, collect the closed fruits and put them into a paper bag. Then whenever the fruits open and the seeds spill out, sow the seeds into well-draining soil in the spring. The round fruit is about .5 inch in length and brown in color.
This shrub performs best if grown in full sun. It also prefers good drainage, and its drought tolerance is high once established. Bottlebrush tolerates any soil except very poor, alkaline, or poorly-drained. It is pest resistant, and its long-term health is usually not affected by pests. If the soil becomes too moist, root and crown-attacking fungus diseases can be a problem. Therefore, keep the plant on the dry side with good air circulation. Chlorosis, a systemic condition which causes new leaves to turn yellow, can be corrected with treatment of the soil using iron sulfate or iron chelate. Fertilize regularly to maintain good flower color and dark green foliage.
The bottlebrush will thrive in warm climates, but it can tolerate the occasional frost or temperatures below freezing for a short time. During the winter months, the bottlebrush should not be watered, which will allow the plant to go dormant. Whenever the weather warms in the spring, begin watering again. Make sure you place the bottlebrush in full sun so it will produce healthy flowers.
To maintain your bottlebrush tree, keep it trimmed and pruned so it can put more energy into producing flowers rather than new branches. Pruning should be done on the new growth, not on the older existing wood near the center of the tree. If you prune too much of the new growth, however, the tree might not produce flowers for a season. On older trees, trimming off older branches will allow it to produce new growth and flowers.
While the bottlebrush can be grown from its seeds, it can also be propagated by cuttings. Take cuttings from the healthiest plants. Find stems that are somewhat mature, but not the oldest or youngest stems. You can place the stems in a bucket of water until roots form and then plant in the ground or plant them directly into the soil and keep the soil moist until the stem is established.
Clear a planting site for the Little John bottlebrush as soon as you can work the soil in the spring. Find a location with moist, well-drained soil and full sun to partial shade. Remove all of the foliage from the area and provide space large enough for the mature size of the dwarf bottlebrush. Dig a planting hole the same depth and at minimum twice the width of the container or root ball. Take the bottlebrush out of the container, loosen the roots, and cut off any damaged, frail, or encircling roots found. Place the Little John bottlebrush in the hole, backfill with the removed soil until nearly full, and then fill the hole with water to settle the soil around the roots. Finish filling the hole and soak the area with water again. Cover the ground around the bottlebrush with a 2- to 3-inch layer of mulch. Do not put any mulch up next to the shrub's stem. Extend the mulch out to cover the area under the shrub's canopy. Water the bottlebrush plants daily for the first 7 days after planting. Water 2 or 3 times weekly for the next month and once weekly after that through the first growing season to establish the plants.
One of the benefits of the bottlebrush plant is the fact that it is extremely low-maintenance and will grow well in the right environment with little care. Once a bottlebrush is established, it is somewhat drought tolerant and does not need much additional watering. If a long drought period occurs, the plant might need to be watered occasionally. If the plant becomes rangy and too straggly for best appearance, it can be pruned back heavily which can restore a more compact shape and encourage new growth.
Since the bottlebrush is also highly disease and pest resistant, it is an ideal plant for the right climate. If planted in the right conditions, a bottlebrush plant should thrive for 20 to 40 years.