27 January 2008

Rubus Brambles of the Central Coast, NSW

Rubus is a world-wide group of prickly, shrubby, scrambling plants. They use their thorns to protect themselves from herbaceous animals and also to enable them to scramble through other shrubs. They are very easy to propagate as they grow readily from stem cuttings and root suckers. There are approximately 250 species of Rubus, including many well-known edible fruits such as raspberry and loganberry, but only about seven species native to Australia. These too have edible fruits, though accounts of their taste vary widely; they have been described as both tasteless and sweet and juicy - perhaps it depends on how hungry you are.

They nearly all have flowers with 5 broad petals and 5 persistent sepals with numerous stamens. The fruits are segments clustered together into an aggregate fruit, which ripens to either red or black depending on the plant.

Possibly the most well-known to Australians is the introduced Rubus fruticosus or Blackberry, which is now a serious pest in many parts of Australia. Less well known are our own native varieties.

Weedy Varieties first
Rubus fruticosus complex (native of Europe). Many very closely-related introduced plants are grouped under this one name because of the difficulty in distinguishing between them. They include:

R. cissburiensis Barton & Riddels
R. laciniatus Willd
R. polyanthemus Lindeb
R. procerus Muller
R. rosaceus Weihe & Nees
R. selmeri Lindeb
R. ulmifolius Schott
R. vestitus Weihe & Nees

Regardless of which name you choose to use they are all erect woody shrubs; up to 5m high, with scrambling prickly stems up to 6m long. They can quickly cover vast areas of the bush, creeks and river banks, road-sides and pastures in temperate high rainfall areas of all States.

They achieve this growth rate because wherever the long shoots touch the ground they are capable of rooting. They grow rapidly and are notoriously difficult to remove. Each piece of root or stem left behind can re-grow in one season.

They have compound leaves of 3 to 5 evenly or irregularly toothed leaflets with prickly petioles. The flowers are white but may shade towards pink, and cluster at the ends of branches.

The ‘berries’ are globular and ripen from green to red to black in late summer.

Our native raspberries turn red when they ripen. These are not yet ready to eat. They will turn black when fully ripe.

The native Rubus species are not quite as troublesome, they include Rubus nebulosus (bush Lawyer) and some which seem quite tame by comparison, for example R.rosifolius ,R. moluccanus var. dendrocharis (syn R. hillii), R. parvifolius.

Rubus rosifolius – Rose Leaf Bramble

This is the one most likely to be mistaken for the introduced blackberry as it looks quite like it until you look very closely. R rosifolius has light-green pinnate leaves of five to seven toothed leaflets (one more set of leaflets to Rubus fruticosus).

It has very prickly stems and backs of leaves

Like R fruticosus (blackberry) it has spreading rhizomes which may produce dense thickets of arching branches up to a metre high. The flowers are quite large and very attractive with five or more large white petals. R. rosifolius flowers and fruits all year round.

Its fruits are more strawberry than raspberry shaped. The fruit is edible but insipid; however it is enjoyed by many native birds.

Again, like the introduced blackberry, this is a very hardy plant which may become invasive if moved from its natural areas. It grows in all soils and conditions, particularly on the margins of rainforests and is an important food source for native birds.

Rubus moluccanus var. trilobus

This plant could not so easily be mistaken for weedy blackberry, though it has the same scrambling habit and long prickly stems. It has similar flowers and fruit, but is a much more genteel plant and is nowhere near as prolific at covering vast tracts of ground.

Its leaves are broadly ovate to heart-shaped, 6 to 10cm long and wide, with finely toothed margins and is rusty-hairy underneath.

Flowers are pink (occasionally white). Fruit is a red globular berry, about 12mm across.
The fruits were part of the diet of the Aborigines and a medicinal drink to relieve stomach upset was made by soaking the leaves in warm water.

The leaves are eaten by a variety of creatures.
Rubus moluccanus var. trilobus grows in sheltered forest and rainforest margins or clearings along the coast zone from Queensland to Victoria. They flower November to February.

Rubus nebulosus
Bush Lawyer

Another one which looks like its relative the blackberry. This one is an extremely prickly plant as the branches and leaf stalks are all covered with numerous prickles. White flowers are borne in loose clusters from the leaf axils and the ripening fruit is dark red. It enjoys similar conditions to the other Rubus and is widespread along the East coast in sheltered forest and margins of rainforests. It flowers October to January.

Rubus parvifolius

Native raspberry, Small-leaf Bramble

A very tiny species, (growing on the Central Coast of NSW the largest terminal leaf is only finger nail size).
It can be a prostrate or a scrambling shrub with finely thorny canes to 60cms long; nowhere near as vigorous as most other Rubus species.
The leaves are compound, with 3 or more leaflets, 5 to 30 mm long, deeply wrinkled and often deeply toothed, silver on the underside. The terminal leaf is larger.
It has papery, persistent sepals and short, pale pink, mauve or red petals. The fruit is edible, small and sweet, again similar to a cultivated raspberry.

It flowers October to December.

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