sicklethorn

Asparagus falcatus
infestation in bushland (Photo: Sheldon Navie)
scrambling habit (Photo: Sheldon Navie
climbing habit (Photo: Sheldon Navie)
habit in flower (Photo: Sheldon Navie)
older woody stems with large thorns (Photo: Sheldon Navie)
close-up of smaller thorns on younger stems (Photo: Sheldon Navie)
thick, whip-like, stem growing from underground tubers, which resembles the young edible stems of garden asparagus (Photo: Sheldon Navie)
close-up of leaves, with finely wavy margins, and flower buds (Photo: Sheldon Navie)
elongated flower clusters (Photo: Sheldon Navie)
close-up of flowers (Photo: Sheldon Navie)
close-up of immature fruit (Photo: Sheldon Navie)
Vine
Whorled
Fern-like
White
Green

A robust climber or shrubby plant with some climbing stems. Its woody older stems are light grey with thorns (5-10 mm long) that are angled downwards. Its 'leaves' (2.5-8 cm long and 2-5 mm wide) are produced in clusters of 3-6 and are either straight or slightly curved. Its small white flowers are arranged in slightly elongated clusters (1.5-3 cm long) in the upper 'leaf' forks. Its rounded fruit (7-10 mm across) are bright red and contain 1-3 seeds.

Common names 
Also known as: sicklethorn, sickle-leaved asparagus, sickle-thorn asparagus,
Family 
Asparagaceae
Deciduous 
No
Flowering time 
Spring - Summer
Native/Exotic 
Exotic
Origin 
Native to eastern and southern Africa and Sri Lanka.
Notifiable 
No
Council declaration 
SIL – Special Investigation List
Known distribution 

Locally naturalised in south-eastern Queensland.

Habitat 

A weed of forests, forest margins, urban bushland, riparian vegetation and gardens.

Habit 

A robust climber or shrub with some climbing stems (i.e. scandent shrub) growing up to 7 m long.

Impact and control methods 

Sicklethorn (Asparagus falcatus) is an emerging environmental weed in south-eastern Queensland. It is occasionally cultivated as a garden ornamental, and like other asparagus ferns (Asparagus spp.) it is spread into nearby bushland areas by birds and other animals that eat its fruit. This species prefers moist semi-shaded situations, and in recent years it has become more and more common in vegetation along waterways (i.e. in riparian areas) in and around Brisbane.

Stem and leaves 

"The older stems are woody and light grey in colour, with hard thorns (5-10 mm long) that are angled downwards (i.e. recurved). The younger stems are smooth, rounded, and hairless (i.e. glabrous).

The leaves are reduced to minute scales and what appear to be the 'leaves' are actually flattened stem segments which function as leaves (i.e. cladodes). Several (3-6) of these 'leaves' (2.5-8 cm long and 2-5 mm wide) are produced in a cluster above each scale leaf. They are hairless (i.e. glabrous), straight or slightly curved (i.e. falcate), and have pointed tips (i.e. acute apices). These 'leaves' are dark green, shiny in appearance, and have a mid-vein."

Flowers and fruits 

"The small white flowers are arranged in slightly elongated clusters (1.5-3 cm long) in the upper 'leaf' forks (i.e. racemes). Each flower is borne on a short stalk (i.e. pedicel) 1.5-4 mm long and has six 'petals' (i.e. tepals or perianth segments). These 'petals' (2.5-3.5 mm long) are white or cream in colour and somewhat oval in shape (i.e. broadly elliptic to obovate). The flowers also have six stamens, usually with white filaments and yellow anthers, and an ovary topped with a short style (about 0.5 mm long) and stigma. Flowering occurs mainly during spring and early summer (i.e. from September to December).

The fruit are rounded (i.e. globular) berries (7-10 mm across) and contain 1-3 seeds. These berries are initially green in colour, but turn red as they mature."

Reproduction and dispersal 

This species reproduces by seed, which are mainly spread by birds and other animals that eat the fruit.

Similar species 

"Sicklethorn (Asparagus falcatus) is similar to the climbing asparagus ferns (Asparagus africanus and Asparagus plumosus ), ground asparagus fern ( Asparagus aethiopicus 'Sprengeri'), bridal creeper (Asparagus asparagoides ), garden asparagus (Asparagus officinalis ), ming asparagus fern (Aspargaus retrofractus) and asparagus fern (Asparagus virgatus ). These species can be distinguished by the following differences:

■sicklethorn (Asparagus falcatus) is a shrubby climbing plant with long-lived and thorny main stems. Its 'leaves' (i.e. cladodes) are borne in groups of three to six along the stems, are elongated in shape, and are quite large (35-125 mm long and 2-5 mm wide). Its flowers are borne in elongated, many-flowered clusters (i.e. racemes) and its fruit turn red or whitish when mature.

■climbing asparagus fern (Asparagus africanus ) is a climbing plant with long-lived and thorny main stems. Its 'leaves' (i.e. cladodes) are borne in groups of more than three along the stems, are linear in shape, and are relatively small (6-15 mm long and only about 0.5 mm wide). Its flowers are borne in small several-flowered clusters and its fruit turn orange when mature.

■climbing asparagus fern (Asparagus plumosus ) is a climbing plant with long-lived and thornless or slightly thorny main stems. Its 'leaves' (i.e. cladodes) are borne in groups of more than three along the stems, are linear in shape, and are very small (4-7 mm long and only about 0.5 mm wide). Its flowers are borne singly or in pairs and its fruit turn black when mature.

■ground asparagus fern ( Asparagus aethiopicus 'Sprengeri') is usually a low-growing or scrambling plant with spreading or drooping branches bearing some small sharp thorns. Its 'leaves' (i.e. cladodes) are borne in groups of one to eight (usually 2-5) along the stems, are linear in shape, and are moderately large (15-25 mm long and 2-3 mm wide). Its flowers are borne in elongated, many-flowered clusters (i.e. racemes) and its fruit turn red when mature.

■bridal creeper (Asparagus asparagoides ) is a creeping or climbing plant with short-lived thornless stems that die back each summer. Its 'leaves' (i.e. cladodes) are borne singly along the stems, are oval (i.e. elliptic) in shape, and are relatively large (10-70 mm long and 10-30 mm wide). Its flowers are borne singly or in few-flowered clusters and its fruit turn red when mature.

■garden asparagus (Asparagus officinalis ) is an upright plant (up to 2 m tall) with short-lived thornless stems that die back each summer. Its 'leaves' (i.e. cladodes) are borne in groups of one to five along the stems, are linear in shape, and are relatively small (12-25 mm long and 0.5 mm wide). Its flowers are borne singly or in pairs and its fruit turn red when mature.

■ming asparagus fern (Aspargaus retrofractus) is shrubby plant with somewhat woody branches bearing some small sharp thorns. Its 'leaves' (i.e. cladodes) are borne in large clusters along the stems, are linear in shape, and are moderately large (8.5-25 mm long and only about 0.5 mm wide). Its flowers are borne in large rounded clusters and its fruit turn black when mature.

■asparagus fern (Asparagus virgatus ) is an upright plant (up to 1.5 m tall) with short-lived or long-lived thornless stems. Its 'leaves' (i.e. cladodes) are borne in groups of three along the stems, are linear in shape, and are relatively small (6-20 mm long and 0.5-1 mm wide). Its flowers are borne singly and its fruit turn orange when mature."