Coast Teatree; refers to its preference for coastal habitats.
Other names:
Australian Myrtle
Australian Teatree
Victorian Teatree
Coastal Tea-tree;
Summary
Coast Teatree (Leptospermum laevigatum) is a perennial, large, scrambling, evergreen shrub to 2-5 m high with greyish green foliage and spiral fissured, stringy bark. The small leaves are oval, leathery and 15-30 mm long by 4-9 mm wide. The single white flowers have 5 small but broad petals spreading above a cup-shaped leathery base. There are numerous stamens that appear to be in a ring but are actually in groups of 5-7 with a group opposite each petal. The domed woody fruit opens by 7-10 valves to release its tiny seeds.
Native to eastern Australia, it is now a serious weed of roadsides and is invading bushland around Albany and also Esperance, particularly in sandy coastal areas.
Description
Cotyledons:
Two.
Leaves:
Alternate.
Stipules - None.
Petiole - Short
Blade - Usually grey green, but occasionally light green or reddish. Leathery, smooth, narrowly egg shaped, widest above the middle, 15-30 mm long by 4.5-12 mm wide with a pointed tip and usually with 3 distinct lengthwise veins. Flat but often cupped at the tip. Tip blunt to rounded
Stems:
Up to 3 m long and 200 mm thick. Tend to scramble with age or may become almost horizontal in windy situations.
Bark is grey, rough, with spiral fissures up the trunk and papery, thin and peeling on young branches. Young branches silky hairy.
Flowers:
1 or 2 on a short stalk? in the leaf axils. 13-20 mm wide, hairless.
Floral tube: 2.5-4 mm long.
Bracts - hairless, brown, deciduous.
Bracteoles - white with silky hairs on the outside. Deciduous.
Ovary - 7-10 celled. Silky hairy or hairless on the top. Style protrudes and is 1 mm long.
Stamens - 22-30, mainly opposite the sepals and one opposite each petal. 2 mm long.
Anthers - 0.7 mm long, versatile.
Fruit:
Capsule 6-8 by 5 mm, splits lengthwise, cup shaped and almost flat topped. Deeply wrinkled with each carpel protruding as a rib. Deciduous but often slow to fall. 8-10 celled. The fruit often releases seed in response to fire or damage to the parent branch.
Seeds:
Many. 2-2.5 mm long. Flattened, often winged on each side.
Roots:
Shallow taproot with many shallow laterals.
Key Characters:
Winged seeds. Most fruiting capsules fall off after a year or two. Leathery, oval leaves.
Biology
Life cycle:
Perennial, shrub up to 3 m tall or small tree. The main flowering period is September-October with an occasional flowering in April. Sexually mature in about 4 years. Can live for 100-150 years, but more commonly only lives for 25-40 years.
Physiology:
Tolerates drought, frost, wind, salt spray and wind blown sand.
Reproduction:
Flowering times:
Mainly September to October. Recorded for April in Perth.
August to November in SE Australia.
Seed Biology and Germination:
Sets large amounts of seed but the viability is usually low. Seed doesn't survive long in the soil and viability quickly drops after one year.
Some of the seed is stored in the canopy in the fruits which open in response to burning or if the parent branch is damaged.
Vegetative Propagules:
Roots where stems contact the ground.
Hybrids:
Allelopathy:
It produces chemicals that reduce the growth of companion plants.
Population Dynamics and Dispersal:
Spread by seed in wind and water mainly. Intentional planting and dumping of garden refuse are common sources of infestations.
Often killed by fire, but this opens the fruits to give a new germination. Fruits also open after branches have been cut or broken.
Seedling mortality in high and typically 1-4 seeds/m2 survive for 5 years and 1-2/m2 for 10 years.
Young plants coppice when cut. Older plants with stems more than 100 mm thick usually don't reshoot when cut.
Roots may form suckers when damaged.
Origin and History:
Victoria, Eastern Australia.
Distribution:
ACT, NSW, QLD, SA, TAS, VIC, WA.
New Zealand.
Habitats:
Climate:
Temperate.
Soil:
Prefers and naturalises on coastal sandy soils. Grown in horticultural situations on many soil types.
Shelter, ornamental, popular hedge plant. Leaves have been used for brewing tea.
Detrimental:
Weed of roadsides, recreational and industrial areas and wastelands. Introduced to Australia as an ornamental, shelter or hedge plant. Little agricultural significance because it does not tolerate cultivation or grazing.
Environmental weed producing thickets to the exclusion of most other species and produces allelopathic chemicals that reduce the growth of companion species.
Toxicity:
No incidence of toxicity recorded. Related species have Citral, an aldehyde, which causes hypertension and damage to the vascular epithelia of eyes.
Legislation:
Not declared in Australia.
Management and Control:
Grazing provides effective control of young plants. Frequent fires before seeding causes local extinction.
Small plants with stems less than 25 mm thick tend to resprouts after cutting. Older plants with stems greater than 50 mm thick rarely sprout if cut close to the ground.
Thresholds:
Eradication strategies:
Slash, fell, bulldoze or mulch thickets, then burn when dry. Spray regrowth until just wet with a mixture of 100 mL of Grazon® plus 25 mL Pulse® in 10 L of water. This treatment has residual action which tends to control seedlings in the following year.
Individual plants can be controlled by applying a mixture of 200 mL of Access® in 10 L of diesel to the lower 50 cm of each trunk in the spring (Summer applications have not been very effective).
Overall spraying with 100 mL glyphosate(450g/L) plus 25 mL Pulse® in 10 L of water is also effective but many seedlings usually appear the following season.
Seedlings can be manually removed in the first year or two. Older seedlings tend to break off and regrow. Small bushes tend to regrow when cut but older bushes tend to die. Grazing will control seedlings.
Plant shrubs and trees 2 years after the last spray to increase the levels of shade.
Coast Teatree roots produce allelopathic chemicals that reduce the growth of companion plants.
Herbicide resistance:
None recorded.
Biological Control:
Low priority because a number of native plants belong to the same genus and infestation levels are relatively low.
Related plants:
West Australian native species of Leptospermum differ in having 3 to 5-celled fruits.
Broom Teatree (L. scoparium).
Lemon-scented Teatree (L. petersonii)
Prickly Teatree (L. juniperinum)
Silver Teatree (Leptospermum sericeum) of granite outcrops near Esperance, has pink rather than white flowers
Homalospermum firmum of wet areas in the west of the region has narrower leaves, only 1-4 mm wide, as well as fewer-celled fruits and is a WA native species.
References:
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide,
South Australia). P603.
Blood, K. (2001). Environmental weeds: a field guide for SE Australia. (CH Jerram & Associates, Australia). P60-61. Photos.
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #739.5.
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). P411.
Moore, J.H. and Wheeler, J.R. (2008). Southern Weeds and their Control. (Second Edition). Department of Agriculture and Food Western Australia. P186-187. Photos.
Wrigley and Fagg (1993) Bottlebrushes, Paperbarks and Tea Trees.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.