Callistemon or Bottlebrush is a genus that we have special interest in at Xera. They may be ubiquitous in California and through out zone 9 – where two red varieties dominate. Callistemon citrinus ‘Splendens’ Zn9a and Callistemon viminalis Zn9b. Neither of these large shrubs, small trees are sufficiently hardy anywhere in the PNW north of Bandon on the southern Oregon Coast. That doesn’t mean we can’t grow some red flowered bottlebrushes. Callistemon (ka’-LIST-ee-mon) which means beautiful stamens- the main structure of the conspicuous flowers-is actually a very large genus- replete with a multitude of species in their native Australia. They occupy nearly every biome on that continent and are aromatic members of the Myrtle family (Myrteaceae)- which also includes Eucalyptus among other cultivated plants. Its those from the highest, alpine elevations of the interior that thrive in our gardens. There are two reds that have been successful in the mildest gardens west of the Cascades.
Callistemon rigidus ‘Woodlander’s Red’ has become a classic red Bottlebrush for the milder PNW (above)
Callistemon rigidus ‘Woodlander’s Red’ is the most commonly seen red variety. It is hardy to Zone 8a (10º to 15ºF), It requires placement in the warmest locations of a garden- against a south or west facing wall or near the reflected heat of asphalt. It can be damaged in our coldest winters (below 10ºF). Recovery happens though if dead parts are removed regular irrigation speeds its re-growth during the dry summer months.
Callistemon subulatus ‘Dark Red’ has some of the deepest sanguine flowers of the genus. It requires the protection of a wall. (above) Xera Plants Introduction
Another red flowered bottlebrush that has shown a fair amount of cold resistance is the species Callistemon subulatus ‘Dark Red’. Its a fine, fine textured arching shrub to 3′ x 5′ in our region. Deep red flowers appear on new growth throughout the growing season. It also blooms well in a pot and can be kept in a container that can be moved into protection when temperatures plunge. It is hardy to about 15ºF and it can vigorously recover if frozen back. (Not all Bottlebrushes have the vigor to regrow and this one does). Place it next to a warm wall, south or west facing. Blooms appear for months. This is a wonderful species for the Oregon Coast (Zn9a).
The Hills are alive with Bottlebrushes
A very hardy species that is wonderful west of the Cascades is Callistemon pityoides or Alpine Bottlebrush.. As its common name alludes it is from the high mountainous regions of Australia- in snowy, frosty conditions. It is a very variable species with the two most common traits fine, needle-like leaves and pale yellow flowers. Nearly 20 years ago, touring a garden in Corvallis I found an Alpine Bottlebrush whose owners pledged that it was growing there and undamaged by cold (that means bouts of 0ºF) for more than 30 years. It is a thin, fine textured shrub with globose small pale yellow flowers that remind me of baby chicks when they decorate each branch tip in May/June and again in September. All selections of this species share the propensity for two seasons of bloom. Callistemon pityoides ‘Corvallis’ grows to 5′ tall and 3′ wide in 10 years. As with all in this genus it absolutely requires full, all day sun to perform. Regular water speeds growth in this species, which is drought tolerant if pressed into that service. It should also be noted that these aromatic and somewhat sparse shrubs are excellent where deer are a problem. These will be left alone or they will be the last thing molested by Bambi in the garden.
Callistemon pityoides ‘Corvallis’ is an alpine bottlebrush that is the hardiest of the genus to 0ºF. The flowers are adorably reminiscent of little fluffy chicks. 5′ tall by 3′ wide. Zone 7a (0º to 5ºF). (above) Xera Plants Introduction
One of our finest discoveries of this species is our selection that we have simply christened ‘Excellent’. Its a crazy growing shrub with the finest needle like leaves that would make a pine tree blush. Its greatest attribute is its 5″ long pale yellow wonderful Bottlebrush flowers (again in spring and then fall). Its a winding, arching shrub with great personality and it is a very, very heavy blooming selection . To 3′ tall and 5′ wide for full sun in any type of soil. Very drought adapted. Cold hardy to Zone 7b (5º to 10ºF)- it shows slight damage below 10ºF- but its recovery is perhaps the fastest of any Callistemon I have grown. This is my own personal favorite Bottlebrush. Its flowers are luminous and cohabitates gracefully with other flower colors. Short of a wacked out conifer, nothing else approaches it in fine textured good looks. New growth in this species is conspicuously furry which is also adorable.
Callistemon pityoides ‘Excellent’ is just that. A subtle flower color and wonderful textural plant. Fine needle like foliage, superior long brushes decorate this graceful plant in May/June and again in September/Ocober. (above) Xera Plants Introduction
Another perfectly hardy species for our gardens is the wonderful Mountain Bottlebrush from Tasmania, Callistemon viridiflorus. This is a remarkably handsome shrub with fantastic leaves, corky, white bark and large beautiful bottlebrush flowers from late May to early July. This is a cold hardy shrub, unperturbed by 5ºF and sports the largest flowers of the hardiest varieties. 1″ wide 4″ long chartreuse/yellow brushes glow from the branch tips and it is a very heavy blooming plant. The nectar filled flowers (as they all have) are obsessed by hummingbirds for the weeks it is in bloom. Almost 10 years ago we did a batch from the seed of a parent plant that had survived 0ºF with light damage, just to see what we might get. Out of hundreds we separated out 4 seedlings that had distinctive traits. Our first selection of that brood is a phenomenal plant that we are proud to grow. We have dubbed it Callistemon viridiflorus ‘Xera Compact’. To just 4′ tall and 3′ wide it is an insanely floriferous shrub, thick, vivid 3″ bottlebrush flowers smother each branch tip. The scimitar shaped foliage lines the stems with a pronounced vertical component that is different than the species. This Mountain Bottlebrush has everything for greatness and we are focusing on making as much as we possibly can. The deep green leaves take on maroon tints in winter- which contrasts with the taupe bark in a wonderful way. Look for this great plant at our retail shop- thats the only place it will be available.
Bottlebrush have the unenviable trait of not looking the best in nursery containers- they really find their own in the ground. So with an open mind and a happy heart try out these Aussies in your garden. We are always on the look out for new selections. Allow yourself to be swept away.
Callistemon viridiflorus ‘Xera Compact’ one of our greatest introductions to date. To only 4′ tall and half as wide, it blooms like a fiend popping off brilliant chartreuse yellow flowers for six weeks from late May to early July. So floriferous and its also perfectly hardy to cold down to 5ºF. (below) Xera Plants Introduction