The Bottle Tree - Brachychiton rupestris
Each time we receive a shipment of Brachychiton rupestris we are further intrigued by the unique forms this species takes on. While other species of plants usually arrive with relative uniformity, Brachychiton rupestris, with their irregular trunks and idiosyncratic branches, each have a completely unique shape which cannot be replicated even if grown in the same conditions.
Like many species that reside within shrubland habitats, this species is well adapted to contending with bush fires. It’s thick, water-storing trunk protects nutrients during high temperatures, which can often trigger a period of flowering and regrowth of leaves following the blaze. It is commonly described as a ‘bottle tree’ due to the rotund shape of the green, woody stem it produces as it matures.
Image 01-02. Unloading a delivery at the entrance to Middleton Mews.
CHOOSING A BRACHYCHITON
The look of the unique trunk paired with the delicate sparse foliage is captivating. Brachychiton leaves are deeply divided, with slender lanceolate leaf blades. These dainty leaves, intricately spread through similarly slim branches are present in plants of all ages; some plants have a more sparse, sculptural silhouette whilst others have grown a much fuller, more lush canopy. But there are a few things to consider when choosing a Brachychiton. First consider the age of the plant, as that particular, swollen and unusually shaped base is more common in older plants. Younger specimens often have an upright shape, usually with a slim single stem with few lateral branches; the contorted, bulbous trunks develop with maturity.
Because of the wide variety of their shape, the trees are catalogued by "Contortion grade" in addition to pot size and height. "Contortion grade" is a measure of the tortuousness of the base of the trunk: the larger the number, the more twists and turns the specimen has.
Image 03. Brachychiton rupestris specimen.
Image 04-05. Trunks of Brachychiton rupestris.
CONTORTION GRADE
The thick, water-storing and contorting trunks of Brachychiton rupestris are their most distinct feature. Each specimen comes with its very own unique shape, even if grown and kept in the same conditions. Some juvenile specimens may already begin a whorled and convoluted growth habit, while other mature specimens might grow with an unusually straight trunk.
While most specimens have a single stem and sit within a snug nursery pot they may have multiple loops or points of contortion. Some may have two stems, each with their own or combined contortion.
Image 06-07. Contortion grade 2 specimen.
The contortion grade measures the loops, turns, and stems of a specimen, assigning a grade where higher numbers indicate a more convoluted shape. The lower end of the scale includes specimen which have a simpler and straighter trunk.
Image 08. Contortion grade 3 specimen.
Image 09. Contortion grade 6 specimen.
Image 10. A mix of small Brachychiton specimens.
CARING FOR THE BOTTLE TREE
Brachychiton originate from subtropical areas of Queensland in Australia, where temperatures can get extremely high during the summer months, but also below freezing at times. These weather extremes make the bottle tree quite hardy, and adaptable to a variety of conditions. Although it can withstand low temperatures, it’s best to keep the plant indoors in the UK climate. Place it in a spot with full sun, ideally a south facing window, or under skylight.
Image 11-12. Comparing different silhouettes of the tree.
As a succulent it is also drought tolerant, but it prefers to be watered regularly during the active growing season of spring and summer. During this time water thoroughly only when the soil has completely dried out, increasing watering gradually once spring starts. During autumn, start to decrease watering, and then refrain from watering during the dormant winter months or once leaves begin to die back.
Image 13. Mature specimens of Brachychiton.
Despite the differences in age and plant height, there can be little variation in pot size until plants reach a much advanced age. Their root systems are relatively small in comparison, and they prefer to be kept in snug pots to reduce the chances of overwatering, as they can store water in their succulent stems for exceptionally long periods. We recommend keeping these plants in their nursery pots for a number of years, or if repotting, ensure the planter has a drainage hole (terracotta planters are ideal) and use a well-draining mix with added pumice, grit, or clay based materials. To encourage new growth during the spring and summer months, feed with a succulent fertiliser every other month.
Image 14. New growth emerging after winter dormancy.
Having cared for several Brachychiton rupestris over the years, as with many plants, you begin to understand them better through time; we have found these 'bottle trees' to be surprisingly low-maintenance both indoors and outdoors despite their delicate appearance and provided they receive adequate sunlight indoors and are kept dry during winter months when temperatures are low outdoors.
Although usually deciduous during the colder months, if temperatures and light levels remain consistent they are less likely to shed their leaves indoors. We have found in our Lower Clapton Road store especially, the warmer of our two locations, specimen retained the majority of their foliage throughout the autumn and winter months. If plants retain their foliage through winter they will shed it when spring comes around, as new growth will push out the old leaves.
SPECIMEN PLANTS
Typically the specimens within our collection are tall but with slender stems and contorted bases, so when we receive a mature specimen it’s particularly special. With age the trunks become exceptionally swollen, no longer the usual contorted silhouette we are used to seeing. Such large sizes of Brachychiton are rarely available, so when these arrive in store they are placed in a category of their own as a 'specimen' plant.
Image 15-16. Mature Brachychiton specimen standing at over 3 metres tall with a 40cm wide trunk.
Image 17. Brachychiton trunks.
All specimens available are located at our physical London stores, so if you're unsure please ask us for images. Email our online orders team via onlineorders@conservatoryarchives.co.uk.