Bulbil Watsonia Watsonia meriana (L.) Miller var. bulbillifera (J.W.Mathews & L.Bolus) D.A.Cooke
Synonyms - Watsonia angusta, Watsonia bulbillifera J. Mathews & L. Bolus, Watsonia leipoldtii, Watsonia meriana (L.) Miller.
Family: - Iridaceae.
Names:
Watsonia honours the English Professor of Botany, Sir William Watson (1715-1787).
Bulbillifera is Latin meaning bulbil bearing.
Bulbil Watsonia refers to the cormels(bulbils) produced in the leaf axils.
Other names:
Bugle Lily refers to the bugle shaped flowers and its membership of the Lily order.
Merian's Bugle Lily honours the botanist Merian.
Watsonia is the common name in New Zealand.
Wild Watsonia refers to its status as a garden escape.
Summary:
Bulbil Watsonia is a hairless, tufted herb with erect, flat, sword shaped leaves to 1 m in length which are produced annually from a corm. The flowering spike is usually unbranched and up to 2.5 m high with many large, salmon pink, trumpet shaped flowers. Each flower has a curved tube and 6 spreading lobes, 15-35 mm long, 3 stamens and a slender 6-branched style. The flowers are usually replaced by cormels at maturity. It reproduces from a large, fibre covered, underground corm and many cormels on the flowering stem and at the base of the leaves.
Native to South Africa, it is now a common in the south west and serious weeds of roadsides, watercourses and railway lines, often invading bushland. They flower in spring and early summer.
Description:
Cotyledons:
One, but none seen as no viable seed is formed.
First leaves:
First shoots are long, thin and grass like.
Leaves:
4-6 leaves arise from the corm.
Cormel derived plants usually only produce 2-3 leaves in their first year.
Blade - Erect, leathery, rigid, folded tightly near the base and flat and strap like above, gradually tapering to a fine pointed tip, fibrous, 300-1100 mm long, 20-50 mm wide, parallel veins. Green on both sides with a prominent yellow midrib and sometimes has a raised yellow vein on each edge. Hairless.
Stem leaves - Short, striped and bract like, clasp the stem, usually reddish, 20-25 mm long. 10-20 cormels or bulbils (5-10 mm diameter) in the axil of each stem leaf.
Stems:
Red brown. scape, erect, stiff, mainly straight, and occasionally branched, with a slight zig zag near the top, round, 700-2500 mm long. Solid, pithy, round and hairless. Usually emerges in late winter to early spring. Often persists from one season to the next carrying bulbils.
Flower head:
Single stalkless flowers in a loose terminal spike, 150-300 mm long with 10-15 flowers spaced 30-40 mm apart.
Flowers:
Salmon pink trumpet shaped flowers, 50-60 mm diameter. Initially erect and drooping to horizontal with age.
Bracts - Red brown, membranous, 18-22 mm long by 10 mm wide with cormels forming in the axils.
Ovary - Style long and slender with 3, forked, pink, 6 mm long branches and arched with the stamens under the upper 'petal'. Style branches pink an about 6 mm long and divided to about the middle into 2 arms.
Perianth - Salmon pink to red with white longitudinal stripes inside the throat. Occasionally pink, purple, red or orange. Funnel shaped, 60-80 mm long, with a curve tubular section and 6 almost equal, slightly spreading lobes. Outer lobes oblong, 20-25 mm long by 7-8 mm wide. Inner lobes egg shaped, 24-27 mm long by 9-11 mm wide with little lobes at the base and the upper lobe arched. Tube 35-55 mm long, curved, swollen upwards but more or less cylindrical near the top, 8-9 mm diameter, and at the bottom, 2.5 mm diameter.
Stamens - Filament long and free and arched with the style under the upper 'petal'.
Anthers - Purple to black, parallel sided, 10-11 mm long, swing freely about their point of attachment.
Fruit:
Cylindrical capsule that normally falls off as cormels are formed.
4-12 cormels, each 6-7 mm diameter are produced at the base of flowers.
10-20 cormels, each 5-10 mm diameter in the axil of each stem leaf.
Cormels globular, usually red brown with curved beak.
Seeds:
No viable seed produced.
Roots:
Fine, shallow, fibrous and short.
Corms - Slightly flattened globular shape, 30-75 mm diameter. Underground at base of plant. Surrounded by a thick, brown to black, fibrous, netted material. Old corm is consumed and 1-3 new corms produced annually.
Key Characters:
Outer floral bract undivided.
Inflorescence unbranched and spike like, or branched.
Flowers sessile with 2 floral bracts, in cymose clusters, distichously arranged on an erect, straight axis.
Leaves usually coriaceous and fibrous.
Perianth tube narrowly cylindric in the lower and broadly cylindric in the upper part.
Perianth lobes more than a third the length of the perianth tube.
Style branches divided into 2 segments.
Cormels(bulbils) present in axils of cauline leaves and floral bracts.
J.M. Black and G. Perry
Biology:
Life cycle:
Perennial with annual tops. Winter growing annual leaves and spring flowers on 1.5-2.5 m high stems. Corms and cormels sprout in autumn and winter. Plants from cormels produce 2-3 leaves and those from corms produce 4-6 larger leaves over winter. Old corms are consumed during winter and a new corm is produced above the old corm annually. Every 2-4 years the plant flowers and two to three new corms are formed. One is often twice as large as the other corm(s). In other years, the old corm is consumed and a new, larger, corm is formed above. The age of the plant can be estimated by counting the number of old corm remnants under the new corm. The corms are usually close to the soil surface. Flowering occurs from October to December but no viable seed is produced, although a small seed capsule may be produced. A number of cormels are formed in the axil of each stem leaf and bract. Aerial growth dies in summer. Plants from cormels take 2-3 years to build up the corm size before flowering. Individual plants have survived for 35 years.
Physiology:
Waterlogging tolerant.
Reproduction:
By corms and cormels.
Flowering times:
October to December in SA and SE Australia.
October to December in Perth.
October to December in WA.
Seed Biology and Germination:
Vegetative Propagules:
Cormels, brown, tear shaped with a curved beak, 6-7 mm wide. In clusters of 10-20 at nodes on the flowering stem.
Up to 34 tonnes of corms per hectare have been recorded in old established stands.
Hybrids:
Probably forms hybrids with Watsonia meriana and is considered by some to be a cultivar of this species. Watsonia meriana has no cormels on the stems.
Allelopathy:
Population Dynamics and Dispersal:
Long distance spread usually by intentional planting, earthmoving or dumping of garden refuse.
Spread mainly by cormels or corms in soil adhering to machinery or in soil. Water flows spread floating cormels. Road making machinery spreads it along road verges.
Cormels are short lived in the soil and few last more than a season.
Bandicoots and rabbits dig for and eat corms. Grey Kangaroos occasionally eat the flowers. Silvereyes feed on nectar from the flower and damage the corolla tube.
Origin and History:
Southern Africa.
Introduced to Australia as an ornamental plant.
Recorded in Adelaide in 1842, NSW in 1843 and Melbourne in 1859.
Distribution:
NSW, QLD, SA, TAS, VIC, WA.
In WA it is in the Avon Wheatbelt, Esperance sand plain, Jarrah forest, Swan coastal plain and Warren.
Mainly in the north west of Tasmania.
New Zealand, USA.
Courtesy Australia's Virtual Herbarium
Habitats:
Prefers wet areas and is tolerant of waterlogging. It will grow on well drained soil but is usually displaced by other species over time.
Sands. Sandy loams over granite, Winter waterlogged soils. Duplex soils. Heavy soils and many other soil types.
Plant Associations:
Significance:
Beneficial:
Ornamental.
Detrimental:
Weed of roadsides, railways, drains, streams, waterways, ungrazed pastures, recreational and industrial areas, wetlands and disturbed areas.
Mature plants are relatively unpalatable but young growth is grazed.
Little agricultural significance because it does not tolerate cultivation or grazing.
Produces almost pure stands in suitable areas excluding almost all other vegetation.
Listed as a "Garden Thug".
Toxicity:
Reported to be toxic, with horse deaths overseas. Animals don't graze mature plants and young plants appear to be non toxic in Australia as no incidence of toxicity has been reported.
Legislation:
Noxious weed of WA, SA, NSW, VIC and TAS.
Management and Control:
Grazing provides effective control. Germinated corms and cormels can be controlled with herbicides. 2,2-DPA provides good control of parent plants and residual action on cormels. Apply from flower stem emergence to mid flowering. Glyphosate also provides good control at this stage. Amitrole T, TCA and paraquat have also provided control.
Cultivation to 100 mm provides good control if done after the old corm is exhausted and before the new corms form or before the flower stem emerges. Dig up plants to determine their stage. A follow up cultivation is also needed.
Establishment of suitable pasture species will prevent reinfestation.
Small infestations can be grubbed but corms must be removed and burnt otherwise they will re shoot if left on the soil surface.
Cormels will develop and mature from stem reserves on stem that are cut at the flower emergence stage or later
Mowing and slashing are ineffective unless repeated very regularly. Slashing at 100 mm or closer to the ground when stems emerge and well before flowering can reduce stem and cormel formation and weaken the corm.
Thresholds:
Not usually a weed of crops or pastures.
Eradication strategies:
1) Graze the infested area continuously during the growing season for several years with sheep or cattle. Burn in summer if significant material remains. Don't graze with horses as it may be toxic.
OR
2) Apply 10 kg/ha of 2,2 DPA plus 0.25% non ionic wetting agent after flower stems emerge and before flowering (September to October) each year for 3 years. This is treatment is partially selective and usually doesn't leave the ground bare. Many scrub species and trees are quite tolerant of DPA so it is a good treatment for overall spraying of roadsides.
Use 1 kg 2,2 DPA plus 250 mL wetting agent per 100 L of water for hand spraying. Spray until the plants are just wet and treat an area of soil about 1 metre diameter around the plant to help control cormels germinating next season.
OR
3) Apply 6 L/ha of Glyphosate (450 g/L) plus 0.25% non ionic wetting agent when the flower stems first emerge (September) each year for 3 years. This is non selective and will kill most other plants sprayed.
Use 1 L glyphosate plus 250 mL wetting agent per 100 L of water for hand spraying. Spray until plants are just wet.
OR
4) In bush land or sensitive areas, apply a mixture of 1 part Glyphosate plus 2 parts water using a sponge (or a sponge glued to a glove) and wipe a third or more of the leaves. Just paint the herbicide onto the exposed Watsonia leaves avoiding the leaves of the desirable species. Repeat this each year in late winter to early spring before flowering.
OR
5) Isolated plants can be dug up by loosening the soil with a fork then pulling the top growth. Be careful not to dislodge cormels from old stems. Burn corms and cormels or bury more than 1000 mm deep. Thick infestations are difficult to control manually.
Cultivation to 100 mm provides good control if done after the old corm is exhausted and before the new corms form or before the flower stem emerges. A follow up cultivation is usually needed. Mowing and slashing are usually ineffective unless repeated very regularly.
Start control at the top of the catchment to reduce re-invasion by cormels carried in water flows.
Eradication from an area can usually be achieved in 2-3 years. Replant shrub and tree species if necessary and treat all infestations upstream.
Herbicide resistance:
Biological Control:
Related plants:
Watsonia aletroides has pink flowers and perianth lobes less than a third the length of the perianth tube.
Watsonia ardernei has not been collected in WA.
Watsonia borbonica has white or pink flowers with white lengthwise stripes inside, a funnel shaped perianth tube which is about 12mm wide at the throat and the tips of the lobes of the outer whorl are shortly acuminate (pointed).
Watsonia knysnana tends to flower later.
Watsonia marginata has pale violet flowers with a white triangular mark often surrounded by a deeper red at the base of each lobe, a funnel shaped perianth tube and 3 staminodes alternating with the stamens.
Watsonia leipoldtii renamed to Watsonia meriana
Watsonia versfeldii has white or pink to lilac flowers, a funnel shaped perianth tube which is about 8-9mm wide at the throat and the tips of the lobes are never acuminate but maybe minutely mucronate.
Watsonia wordsworthiana renamed to Watsonia borbonica
Plants of similar appearance:
African Cornflag (Chasmanthefloribunda) is very similar but has yellow or red and yellow flowers, no cormels(bulbils) and its 3 style branches are undivided.
Freesia (Freesia leichtlinii) is similar but much smaller.
Gladiolus spp. is similar but comes in many colours other than salmon pink and its 3 style branches are not divided.
Harlequin Flower (Sparaxis spp.)is similar but much smaller.
Montbretia (Crocosmia x crocosmiiflora) Looks very similar to African Cornflag but flowers from November to March and has stolons.
Native plants which (when not flowering) may be confused with Watsonia are Kangaroo Paws (Anigozanthos species) with darker green, fleshier, unribbed leaves, that are often mottled with dark markings on the older leaves. The dried flower spikes are broad and branched in the common south west Tall Kangaroo Paw (Anigozanthos flavidus).
Patersonia and Orthrosanthus species have leaves which are generally narrower and often bear a few marginal hairs.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P28. Photo.
Black, J.M. (1978). Flora of South Australia. (Government Printer, Adelaide, South Australia). P383. Diagram.
Blood, K. (2001). Environmental weeds: a field guide for SE Australia. (CH Jerram & Associates, Australia). P164-165. Photo.
Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P36-37. Photos.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #1278.2.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P805.
Meadly, G.R.W. (1965). Weeds of Western Australia. (Department of Agriculture - Western Australia). P59-62. Diagrams. Photo.
Moore, J.H. and Wheeler, J.R. (2002). Southern Weeds and their Control. 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). P99-100. Photos.
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). P73.
Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P79-81. Photos.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.
