Bottlebrush, Bottle Brush 'Harkness'


Family: Myrtaceae (mir-TAY-see-ee) (Info)
Genus: Callistemon (kal-lis-STEE-mon) (Info)
Cultivar: Harkness



Foliage Color:

Unknown - Tell us

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Water Requirements:

Drought-tolerant; suitable for xeriscaping

Where to Grow:

Unknown - Tell us


12-15 ft. (3.6-4.7 m)


12-15 ft. (3.6-4.7 m)


USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:

Full Sun


Unknown - Tell us

Bloom Color:


Bloom Time:

Late Winter/Early Spring

Mid Spring

Late Spring/Early Summer

Mid Summer

Late Summer/Early Fall

Mid Winter


Grown for foliage

Other details:

Unknown - Tell us

Soil pH requirements:

5.6 to 6.0 (acidic)

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

Patent Information:


Propagation Methods:

From woody stem cuttings

From semi-hardwood cuttings

From seed; direct sow after last frost

Seed Collecting:

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed


This plant has been said to grow in the following regions:

Tucson, Arizona

Fort Walton Beach, Florida

Lady Lake, Florida

Rincon, Georgia

Madisonville, Louisiana

Tomball, Texas

show all

Gardeners' Notes:


On Oct 15, 2017, Kell from Northern California, CA (Zone 9b) wrote:

Per Gill Muller of Port Elliot, South Australia about her photos of this plant:

"The red Callistemons are in full flower all over Port Elliot and other towns on the Southern Fleurieu, I'm sure they are in Adelaide and everywhere else too!
Callistemon 'Harkness', also known as 'Gawler Hybrid' would have to be one of the hardiest, most floriferous of the reds, also one of the largest! Planted extensively in SA as a street tree, it's a bird magnet at this time of year, particularly for the Rainbow and Musk lorikeets around here.
I had planned on going on a hunt for some good ones, then when I looked at the ones in my street I realised I didn't have to go very far! I wanted to find some Callistemon 'Kings' Park Special' as well, I think that's another beauty, they... read more


On Jun 3, 2016, Streliziapete from Mel,
Australia wrote:

Beautiful Bottle brush. Rumoured to be a hybrid of callistemon Viminalis, it originated in Gawler South Australia. Very long (over 20 cm) blood red thick spikes in Spring and Autumn. This one is a little slower growing than the similar kings park special and has different leaves the flower color is also a bit lighter and the leaves are a light green.


On Sep 22, 2009, Stake from Barmera,
Australia wrote:

Callistemon "Harkness" or "Gawler Hybrid" sets very little seed and cannot be reliably propagated by this method. The only sure way as with other hybrids is by vegetative reproduction.
This hybrid was in a batch of plants grown by Mr GLH Harkness in 1937 at Gawler Sth Aust. but not reproduced until 1948 when it was recognised as one of the best of all Callistemons and it has not been surpassed since for its ability to produce large numbers of big bottle brush flowers. It is widely used as a street tree in Sth Aust Towns and can attain a height of 20 ft or more but is usually more like 12ft.


On Jun 26, 2007, southernbeauty from Madisonville, LA (Zone 8b) wrote:

There are 34 currently called Callistemon, it is sometimes difficult to tell which genus the species belong to. Bottlebrushes can be found growing from tropical north to temperate south, they often grow in damp or wet conditions, (along creek beds or in areas prone to flooding). the flower spikes can be red or yellow, the flower produces small woody fruit which contains hundreds of tiny seeds, the seeds are usually not released from the fruits for several years, most species are very hardy and will tolerate drought and are low maintenance. Plants grown in full sun produce the best flowers, I have also seen Bottlebrush thrive in Anaheim California, and have always loved the spectacular flowers and the way the birds and insects find it irresistible.