South African Asparagus Fern

South African Asparagus Fern

Asparagus aethiopicus

Synonyms - Asparagus densiflorus, Asparagopsis densiflora, Asparagus myriocladus, Asparagus sarmentosus, Asparagus sprengeri, Protasparagus aethiopicus, Protasparagus aethiopicus, Protasparagus densiflorus

Family: - Asparagaceae or Liliaceae.

Names:

Asparagus is the ancient Greek name for the Asparagus vegetable.

Aethiopicus is the Latinised form of Ethiopia which was often used by Linnaeus to indicate plants from South Africa.

Other Names:

Fern Asparagus

Sprengeri Fern

Ground Asparagus

Basket Asparagus

Summary:

South African Asparagus Fern is a perennial prickly scrambler with annually renewed tough shoots. It doesn't die back completely over summer like Bridal Creeper and green stems are present all year in most environments. It has a rootstock with many tubers. The spines are 2-10 mm long in the axils of the branchlets of older stems. There are 2-5 'leaves' per axil, and they are narrowly elliptic, straight to slightly curved, 1.5-2.5 cm long and 2-3 mm wide, usually with 1 much longer than the others. The flowers are bisexual, white to pinkish with petals 3-4 mm long. The berries are globular, red when ripe and 5-8 mm across.

Native to southern Africa, South African Asparagus Fern is now an invasive weed along the south coast and flowers from March to April.

Description:

Cotyledons:

One.

Leaves:

True leaves are tiny and scale like at the base of leaf like structures called cladodes.

"Cladodes" look like leaves but actually are flattened, leafless branches that arise from the axil of the branchlet and the scale-like true leaf.

Cladodes (Leaf like structures) - 2-5 in a single plane in each leaf axil and of unequal length with one noticeably longer. They are shiny green and usually straight to slightly curved and flattened and 15-25 mm long by 2-3 mm wide with a distinct midrib. Cladode sets alternate up the stem. Tip pointed with a finer point (apiculate). Sides parallel. Base tapering. Hairless.

Stems:

Many, wiry, tough, slender, green to light brown, sprawling then climbing and twining. There is a 2-10 mm spine in the axils of the branchlets but young stems may be spineless

Many branched. Up to 3000 mm long by 1-2 mm diameter. Circular to ridged to angular in cross section and often twisted. Hairless

Flower head:

An axillary raceme, 40-100 mm long usually near the ends of the stems.

Flower stalks (pedicels) 5-10 mm long and jointed in the lower half.

Flowers:

White to pinkish, small (6-8 mm diameter) with 6 petals (tepals) topped by yellow anthers. Somewhat bell shaped.

Ovary - Superior. 3 cells. Simple style.

Perianth - 6-8 mm diameter. 6 widely spreading segments (tepals) 3-4 mm long and free.

Stamens - 6.

Anthers - Yellow. Open inwards with slits.

Fruit:

Globose, sticky, succulent berry. 5-8 mm diameter. Initially green turning red when ripe and may remain on the plant until the next flowering season. Each fruit usually has one seed or occasionally two.

Seeds:

Black, shiny. Egg shaped to globular, 3-4 mm diameter.

Roots:

Fibrous, rhizomatous and with a thick mat of tuberous roots. Tubers form on the fleshy rhizome or laterally on the fibrous roots.

Xxx A perennial, short, branching rhizome surrounded by many tubers with white flesh all within the top 200 mm of soil. The tubers are 25-40 mm long by 8-20 mm diameter. Many fibrous roots anchor the rhizome and tubers. It will reshoot from the rhizome but not the tubers (unless there is a bit of rhizome attached).

The tubers are long lived.

Key Characters:

Cladodes flattened, in sets of 2-4

Cladodes 2-3 mm wide and mostly 15 mm long.

Perennial green stems.

Tepals free

Flowers bisexual.

Red berries.

Adapted from Harden

Biology:

Life cycle:

Mediterranean areas;

Seed germinate at any time of year when the soil is moist with a flush in autumn and a smaller flush in spring and grow slowly while the root system forms then aerial growth increases quickly. Tubers form in mid summer. Most plants will not flower in their first year. Flowering usually starts in October and continues until March with the odd flower being present through to June. Some fruit is usually present on the plants all year round. Green berries ripen to red at maturity. The ripe fruit may remain on the plant for some time. The stems are perennial and the plant usually remains green all year. Each spring new growth emerges from the rhizomes.

Physiology:

Tolerates full shade to full sun and grows best in partly shaded areas.

Tolerates drought and saline soils.

Reproduction:

By seed and rhizomes.

Flowering times:

March-April in WA.

Mainly spring to summer in NSW, fruits all year.

Summer to autumn in SE Australia.

Seed Biology and Germination:

Germination rates of the seed are usually high and there appears to be little dormant seed.

Vegetative Propagules:

Rhizome supported by a mass of tubers.

Hybrids:

Allelopathy:

Ecology, Population Dynamics and Dispersal:

Reproduces by both seeds and rhizomes.

The initial spread was mainly due to intentional planting in gardens. This was followed by spread due to the dumping of garden refuse containing the mats of tubers and rhizomes together with seed.

In undisturbed situations, most of the seed falls close to the parent plant. However birds are major contributors to its dispersal. Most new infestations can now be attributed to dispersal by birds. On the south coast of WA, spread rates due to bird dispersal are about 20 m/year. Rabbits and other animals may also spread it in their droppings. Water borne seed dispersal also occurs along creeks with dense germinations occurring at the high water mark where seed is deposited with debris. Once established the size of the infestation increase slowly with seedling establishment at the perimeter of the clump and extension of the rhizome

Local spread can also occur from seed in mud on machinery or sticking to animals and clothing. Rhizomes are spread by road making machinery along roadsides or by cultivating machinery. Seed is spread in water flows and both seed and rhizomes are spread in dumped garden refuse.

It will tolerate moderate shade and can invade relatively undisturbed bushland as well as open woodland areas. It is generally not found in totally cleared areas or healthy bushland.

After invasion, it smothers most species that grow less than 2 metres tall.

The tuber mass competes with germinating plants and inhibits water penetration.

Green fruit will ripen on the vine.

It generally prefers moister and shadier sites than Bridal Creeper.

Origin and History:

Native to Southern Africa.

Introduced to Australia in the late 1800's as an ornamental plant and has been planted widely in gardens.

Distribution:

NSW, QLD, SA, WA.

Swan Coastal Plain, Jarrah Forest and Warren regions of WA.

Extensively naturalised in NSW.

Habitats:

Prefers shaded situations but still grows well in full sun.

Often found in coastal locations.

Climate:

Warm temperate, Mediterranean and tropical climates.

Grows within a temperature range of 10-20 degrees C and annual rainfall of 500-1500 mm.

Soil:

Flats between dunes, embankments, headlands, hills.

Prefers sandy soils and well drained, light textured, fertile soils.

Plant Associations:

Found along creeks.

Eucalyptus, Banksia and Agonis woodlands.

Coastal heath, wet sclerophyll forests, dry sclerophyll forests, woodlands, riparian vegetation, shaded woodlands, rock walls, hedges, heathland.

Significance:

Beneficial:

Ornamental.

Detrimental:

Weed of bushland, roadsides, creek lines and gardens.

Invasive forming dense mats that exclude most other species and prevent regeneration of overstorey species.

In many situations it has minor impact but given the right conditions it can be a serious environmental weed. It is a serious weed of New Zealand and Lord Howe Island.

Toxicity:

Not recorded as toxic.

Legislation:

A declared noxious weed of Lord Howe Island and parts of NSW.

Management and Control:

It does not persist under grazing.

Manual control is very difficult on established infestations but seedlings and juveniles can be pulled successfully if the ground in loosened to ensure the rhizome is removed with the plants. Burn all seed and rhizome fragments.

The following have been methods have been used by environmental groups:

1) In winter to early spring, apply 1-2 g metsulfuron (600g/kg) per ha plus 25 mL Pulse Penetrant per 10 L of spray mix with a mister. This can be used as an overall spray in bushland situations and rarely causes significant damage to native species. Try a small area on your set of species to determine if there are sensitive species present. For spot spraying mix 1 g metsulfuron (600g/kg) plus 250 mL Pulse Penetrant in 100 L water and spray foliage until just wet. Results may not be seen until the following season.

2) Slash or Whipper Snip the stems regularly before they form buds. This may take several years to reduce root reserves and achieve control.

3) Dig up, crush and burn the tubers and root system.

4) Manually apply a mix of 1 part glyphosate in 3 parts water to leaves and stems with a sponge glove or paint brush taking care to avoid companion species.

Around 90% control has been achieved with metsulfuron plus glyphosate mixtures. In WA a mix of 1 part glyphosate in 50 parts water plus a marker dye is used on heavy infestations and is considered to be less deleterious to bushland than glyphosate plus metsulfuron or chlorsulfuron mixtures.

The best time to apply herbicides is probably just before flowering.

Fire may also be a useful tool. After burning, as Asparagus Fern is often the first plant to emerge, thus allowing the use of non selective herbicides and assisting access to infestations.

Tuber mats can be scalped with earth moving equipment in open situations.

Large infestations are targeted for control because these produce the most seed for transport by birds. Others opt for the alternate strategy of controlling peripheral light infestations first.

If vines are manually removed they usually need to be burnt or buried because they often carry old fruit and green fruit that will ripen on the vine.

Avoid using machinery that will move the rhizomes such as cultivators, graders and earthmoving equipment in infested areas.

Eradication strategies:

Eradication is only likely to be successful if seed set is prevented to stop the spread by birds.

Manual control is difficult due to the extensive tuberous root system which requires removal and the somewhat spiny stems.

Low rates of 10 g/ha metsulfuron(600g/kg) plus Pulse® or 0.2 g metsulfuron plus 25 mL Pulse® per 10 L water provides good suppression when sprayed onto the foliage until just wet in July or August before flowering with little damage to many established native species.

2 g/ha metsulfuron (600g/kg) plus 25 mL Pulse per 10 L of spray mix applied with a mister in July or August has given selective control in roadside bush. The herbicide is slow acting and full effects may not be seen until the following season. Repeat annually or until the plant disappears.

Applying a mix of 1 L glyphosate(450g/L) plus 2 L water to leaves and stems with a sponge glove or brush and avoiding other species is slower but more selective.

Grazing or persistent removal of the tops for several years exhausts the tubers. Intense fire can kill some of the tubers and clear the area to allow spraying of the regrowth with 100 mL glyphosate(450g/L) plus 1 g metsulfuron in 10 L water before other species germinate or reshoot.

Burial is not usually effective.

Prevent reinfestation by birds by treating all areas on a district basis.

Replant shrub species.

Herbicide resistance:

None reported.

Biological Control:

Biocontrol agents introduced for Bridal Creeper control have little effect on this species.

Related plants:

See A key for the weedy Asparagus species

Asparagus (Asparagus officinalis) is a cultivated vegetable.

Asparagus fern (Asparagus scandens = Myrsiphyllum scandens) has perennial stems that don't die back in summer and has single seeded berries that are orange-red when ripe. There are separate male and female plants.

Baby Smilax or Myrtifolius (Asparagus asparagoides) is a compact dwarf form of Bridal Creeper and sold in nurseries.

Bridal Creeper (Asparagus asparagoides) = Myrsiphyllum asparagoides is an aggressive climber with leaf like phyllodes and red to purple berries.

Bridal veil (Asparagus declinatus = Myrsiphyllum declinatum = Asparagus crispus) has egg shaped berries that are light green ripening to translucent white.

Cutleaf Self-heal (Protasparagus laciniata)

Climbing Asparagus Fern (Asparagus plumosus = Protasparagus plumosus) has perennial shoots with recurved spines.

South African Asparagus Fern (Asparagus aethiopicus) has thorny stems with creamy white to pink flowers.

Native Asparagus Fern (Protasparagus racemosus)

Self-heal (Protasparagus vulgaris)

Asparagus africanus = Protasparagus africanus is similar to Asparagus plumosus.

The Asparagaceae family has recently been separated from the Liliaceae family. Asparagaceae is currently considered to have one large variable genus Asparagus with 2 sub genera Asparagus and Myrsiphyllum (Keighery, 1996).

Asparagus species of WA

Current name	Status	Old names
Asparagus aethiopicus L. Mant.Pl. 63 (1767)	Alien	Protasparagus aethiopicus	Asparagus densiflorus (misapplied)
Asparagus asparagoides (L.) Druce Bridal Creeper	Alien	Myrsiphyllum asparagoides
Asparagus declinatus L.	Alien	Myrsiphyllum declinatum (L.) Oberm.	Asparagus crispus Lam.
Asparagus officinalis L. Asparagus	Alien Vegetable
Asparagus plumosus Baker	Alien	Protasparagus plumosus
Asparagus racemosus Willd.	Native from Kimberly area	Protasparagus racemosus
Asparagus scandens Thunb.	Alien	Myrsiphyllum scandens
Asparagus virgatus	Alien. Not in WA.	Protasparagus virgatus
Asparagus africanus	Alien. Not in WA.	Protasparagus africanus

Plants of similar appearance:

Apple-berries (Billardiera species) differ with their more leathery leaves, flowers with 5 sepals and 5 petals and fruits which are hard rather than succulent and usually more or less cylindric in shape.

Lignums (Muehlenbeckia species) differ in having tiny flowers in clusters, each flower with 5 petals.

Slender Clematis (Clematis linearifolia) differs in having opposite leaves which are divided into 3 stalked leaflets and fruitlets in a head (each fruitlet with a long feathery awn).

Small-leaved Clematis (Clematis microphylla)

Native Smilax species

Scrambling Lily (Geitonoplesium cymosum) is a native.

Selliera radicans is not a climber but creeps along the ground with roots at each node. It also has stalked leaves and fan-shaped flowers. It occurs in saline, estuarine areas of the Warren region.

Wombat Berry (Eustrephus latifolius)

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P30. Photo.

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 4. P46. Diagram.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (2007). Western Weeds. A guide to the weeds of Western Australia. (Second Edition). Plant Protection Society of Western Australia, Perth, Western Australia. P12.

Keighery, Greg (1996). Native, naturalised and cultivated Asparagaceae in Western Australia. Plant Protection Quarterly, 11(2): 49-50.

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #820.3

Moore, J.H. and Wheeler, J.R. (2008). Southern Weeds and their Control. (Second Edition). Department of Agriculture and Food Western Australia. P147-147. Photos.

Muyt, A. (2001). Bush Invaders of South-East Australia: a guide to the identification and control of environmental weeds found in South East Australia. (R.G and F.J. Richardson, Australia). P124. Photos.

Parsons, W.T. and Cuthbertson, E.G. (1992) Noxious weeds of Australia. (Inkata Press, Melbourne). P47.

Paczkowska, G. and Chapman, A. (2000). The Western Australia flora: a descriptive catalogue. (Wildflower Society of Western Australia (Inc), the Western Australian Herbarium, CALM and the Botanic Gardens & Parks Authority). P37.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.