Quilpie Mesquite

Prosopis velutina
Tree
Opposite
Compound
Cream
Green

Species vary in growth characteristics. Quilpie Mesquite can occur as a multi-stemmed shrub with branches drooping to the ground, around 3–5 m high, or as a single-stemmed tree with a spreading canopy growing to 15 m.

Common names 
Also known as: Algaroba, Cloncurry Prickle Bush , Quilpie Algaroba,
Family 
Mimosaceae
Deciduous 
No
Flowering time 
Spring - early summer
Native/Exotic 
Exotic
Origin 
Native to North and South America
Notifiable 
No
State declaration 
Category 3 - Must not be distributed or disposed. This means it must not be released into the environment unless the distribution or disposal is authorised in a regulation or under a permit.
Council declaration 
As per State Declaration
Known distribution 

Mesquite has spread along waterways and floodplains, along roadsides, and in horse-paddocks near homesteads across Queensland.

Habitat 

Mesquite was originally favoured as a shade tree around homesteads and as fodder for stock. However, sparse stands will often form into impenetrable thickets. Many infestations are along waterways, both natural and constructed. However, plants will do just as well away from water. Even in rangelands it is an aggressive competitor and can quickly invade upland country.

Habit 

A shrub either single or multi-stemmed.

Impact and control methods 

Foliar spray
Quilpie Mesquite were introduced to Australia as fodder for stock, ornamentals in station homestead or town gardens, and used in mine dumps and other soil stabilisation programs. It is a prohibited invasive plant under the Biosecurity Act 2014. The Act requires that all sightings of Mesquite be reported to Biosecurity Queensland within 24 hours. By law, everyone has a general biosecurity obligation (GBO) to take all reasonable and practical steps to minimise the risk of Quilpie Mesquite spreading until they receive advice from an authorised officer.

Stem and leaves 

Older bark is rough and grey or brown. Small branches have smooth bark, dark red or green in colour, and in a zigzag shape. Mesquite has a rather untidy appearance, with individual zigzagged twigs sticking out beyond the main canopy. Leaves are fern-like in appearance. Each leaf has 1−4 pairs of leaf branches (pinnae), with each ‘branch’ having 6−18 pairs of individual leaflets. Leaflets vary from oval-shaped to long and narrow depending on the species. Foliage is usually dark green but can vary to bluish green. Paired thorns usually occur just above each leaf axil.

Flowers and fruits 

Flowers are small greenish-cream ‘lamb’s tail’ shaped that grow near the ends of branches in wattle-like spikes, 5–12 cm long. Seed pods are 10−20 cm long, straight to slightly curved, smooth, with slight constrictions between the seeds. When ripe the pods are straw-coloured, or purplish in some species. Each pod contains between 5−20 hard seeds.

Reproduction and dispersal 

Generally, the first flowers and seeds are produced when they are between two and five years old, although pod production within one year has been observed under ideal conditions. The flowers predominantly emerge in spring and early summer, with pods taking two to three months to mature. Mesquite plants can produce large quantities of seed, although the number of pods produced by trees can vary greatly from year to year, and from plant to plant. Several mesquite species are known to be self-incompatible, which means they require cross-fertilisation between plants before pods can be produced.

Similar species 

Mesquite (Prosopis pallida)