Lemon bottlebrush is an exceptionally beautiful plant that positively drips with distinctive red flowers that look like bottlebrushes. It can be grown here, but it’s not ideally suited to grow in the desert southwest. Here’s everything you need to know about planting and taking care of this Australian native.
Lemon bottlebrush (Callistemon citrinus) is an eye-catching plant that gives desert-dwellers a feeling of being in a tropical oasis.
It can be grown as either a large shrub or small tree. Its narrow, leathery, evergreen leaves start out tinged with copper. It’s unique fuzzy flowers form at the end of branches, creating graceful cascades of crimson.
The name lemon bottlebrush refers to the minty-lemon scent that’s released when its leaves are crushed.
Its striking red flowers attract hummingbirds and bees like crazy!
Why I Like This Plant
- Show-stopping floral display
- Garden friendly — no thorns, non-toxic
- Attracts hummingbirds and bees
Things to Watch Out For
There are many Australian native plants that are beautifully suited to grow in the desert southwest — the various emu bushes and some acacias come to mind. These plants are native to Australia deserts and tolerate our extreme heat and alkaline soil.
But lemon bottlebrush has a very different natural habitat. It grows in acidic soil along creek beds, in swampy areas, and in areas prone to floods.
Consequently, it is a moderate (rather than low) water use plant that is extremely susceptible to developing iron chlorosis.
It also has brittle wood, which makes it prone to storm damage. (I lost one to monsoon wind and was heartbroken. 🥹 )
While researching this plant, I was surprised to read how bad some of its press was.
Arizona State University’s online plant library called this plant “mostly useless in Phoenix” due to its soil incompatibility, propensity to developing chlorosis, and its struggle in extreme heat.
Southern California’s water conservation site, Waterwise Garden Planner, states that, “we would not recommend installing this plant in new gardens, landscapes, or plantings in southern California.”
So while lemon bottlebrush can be grown here (I’ve seen some spectacular specimens), it could be a challenge, depending on your situation.
Optimal Growing Conditions
If you’re still thinking of adding a lemon bottlebrush to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Lemon bottlebrush should be grown in USDA Hardiness Zones 9 – 11. It is cold hardy down to around 15°F and is relatively heat tolerant. However, plants struggle when temperatures go above 110°F, as they often do in our hottest areas.
Sun Exposure
Lemon bottlebrush is usually grown in full sun. It can be grown in part shade, but will have fewer flowers.
Size and Growth Rate
Lemon bottlebrush is considered a moderate grower, and a typical specimen will eventually reach a size of 15 feet tall by 10 feet wide. But if a plant is happy with its location and care, it can grow much bigger — up to 25 feet tall by 20 feet wide.
Soil
In its native habitat, lemon bottlebrush grows in acidic sandy or loam soil. So as you can imagine, our dry, rocky, alkaline desert soil is not ideal. Plants will tolerate most well-draining desert soil types, but may develop iron chlorosis.
Lemon Bottlebrush:
The Essentials
| Common Name | Lemon bottlebrush |
| Scientific Name | Callistemon citrinus |
| Origin | Australia |
| Plant Type | Evergreen shrub, tree |
| USDA Zones | Zones 9 – 11 |
| Cold Hardy | To 20℉ |
| Flower Color | Red |
| Flower Season | Spring, summer, fall |
| Mature Size | 15’ high x 10’ wide |
| Growth Rate | Moderate |
| Sun Tolerance | Full, part sun |
| Water Needs | Moderate |
| Pests & Diseases | Iron chlorosis |
| Garden Friendly | No thorns, non-toxic |
| Wildlife | Attracts bees, hummingbirds |
How to Plant
The rule of thumb when planting any shrub or tree in the desert is to dig a hole three times as wide as the root ball but no deeper. Since it prefers fertile, acidic soil, consider amending your hole with compost or a commercial soil mix.
Top with organic mulch rather than gravel, which helps to retain moisture, increase soil fertility, and reduce alkalinity.
When to Plant
The best time to plant lemon bottlebrush is in the fall. This gives your shrub three seasons to grow roots and get established before the following summer.
The second best time is in spring, the earlier the better. This still gives your plant time to get established before the intense heat of June arrives.
How to Care for Lemon Bottlebrush
Whether you’ve recently planted a lemon bottlebrush or have an existing plant in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water New Plants
Once you’ve got your bottlebrush in the ground, watering is your most immediate concern. Here is the recommended watering schedule for new shrubs planted in the spring or fall.
| Weeks 1 & 2 | Every 3 – 4 days |
| Weeks 3 & 4 | Every 6 – 7 days |
| Weeks 5 & 6 | Every 7 – 10 days |
| Weeks 7 & 8 | Every 10 – 14 days |
After week 8, gradually extend the time between waterings.
How to Water Established Plants
As your shrub gets established, there are two watering factors to consider.
- First is how often to water. This will vary with the seasons.
- Second is how much water to give your shrub with each watering. This depends on the current size of your plant.
To determine the ideal watering schedule for any desert shrub, you’ll find everything you need to know, including easy-to-use charts, at How to Water Desert Shrubs: How Often? How Much? (Be sure to use the “high water use” chart, not the “desert-adapted” chart.
Should You Fertilize?
As a non-native and prolific bloomer, lemon bottlebrush benefits from an annual or semi-annual application of fertilizer.
If your plant’s leaves are turning yellow, it may have iron chlorosis. You can learn how to identify and treat iron chlorosis here.
How to Prune
Lemon bottlebrush naturally grows as a large, multi-trunked shrub and needs little pruning. However, if you chose to shape it as a tree, I urge you to hire a certified arborist (not a landscaper) to prune it. Correctly training a shrub to grow as an attractive, healthy tree is a special skill that the typical landscaper rarely has.
While lemon bottlebrush can be trimmed as an informal hedge, frequent pruning will reduce flowering, which defeats the main reason people grow it.
Lemon Bottlebrush Hybrids
Lemon bottlebrush comes in several hybrids. Interestingly, most hybrids grew spontaneously and were discovered as opposed to being deliberately bred.
Lemon bottlebrush typically has red flowers, but there are several other colors to choose from. Here’s a sampling of varieties you may come across when plant shopping and their flower color:
- ‘Mauve Mist’ (mauve)
- ‘Burgundy’ (purple-red)
- ‘White Anzac‘ (white)
- ‘Reeves Pink’ (pink)
Don’t Confuse Lemon Bottlebrush With…
Bottlebrush is sometimes confused with Baja fairy duster, a native of the desert southwest. Not only do they both have feathery red flowers, they also have similar-sounding scientific names — fairy duster’s Calliandra to bottlebrush’s Calliestemon.
BTW, Baja fairy duster makes an excellent, easy-care alternative to bottlebrush if you’d prefer to “plant native.”
Plant Lover Facts
Lemon bottlebrush (Callistemon citrinus) also goes by the common names scarlet bottlebrush, red bottlebrush, and crimson bottlebrush. You can just call it “bottlebrush,” but it may get confused with one of the many other plants that go by that common name.
The genus name Callistemon means “beautiful stamen” in Greek, and citrina means “lemon scented.”
You may also see this plant go by the scientific name Melaleuca citrina. There’s an ongoing debate as to whether Callistemon should be a separate genus or should be moved into the Melaleuca genus.
Many authorities now put Callistemon in the Melaleuca genus, but there are two reasons I didn’t do that here.
First, the nursery trade uses Callistemon almost exclusively, and I want you to find the right plant when you go shopping or looking for information. And unless you’re a botany nomenclature geek, you’re probably OK with that. 😉
Additionally, the Australian Plant Census, which is “the” authority on Australian plant nomenclature, is not on board with moving these plants to the Melaleuca genus. And I am happy to defer to their wishes.
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for over 15 years.
