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Feature Pest: Mother-in-Law’s Tongue

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Native to some parts of tropical western Africa (i.e. Zaire and northern Nigeria), mother-in-law’s tongue (Sansevieria trifasciata) is regarded as an environmental weed in Queensland, New South Wales and the Northern Territory, and as a “sleeper weed” in other parts of Australia.

The creeping underground stems (i.e. rhizomes) are relatively thick and somewhat fleshy. They are usually bright orange on the outside and whitish on the inside.

Mother-in-Law’s Tongue with its distinctive leaves and flower spikes

The large sword-shaped or elongated leaves are upright (i.e. erect) and usually arranged in small clusters of 2-6 leaves. These leaves (30-175 cm long and 2.5-9 cm wide) are also thick and somewhat fleshy (i.e. succulent) with sharply-pointed tips. They have entire margins, are hairless, and are relatively long-lived. Both leaf surfaces are dark green and variegated/irregularly striped and banded with pale green or whitish-green. 

The upright flowering stems are relatively slender and usually shorter than the leaves (30-75 cm long). They bear numerous flowers in elongated clusters near their tips. The flowers are white, yellowish-white or greenish-white in colour and are usually arranged groups of 1-3 along the flowering stems. Flowering occurs mostly during spring and summer (i.e. from September to February). The small rounded fruit is a berry that turns from green to bright orange as it matures, containing two seeds.

This species reproduces by seed and also vegetatively via its creeping underground rhizomes. The seeds are dispersed by birds and other animals that eat the brightly coloured fruit. The creeping underground can spread some distance and greatly increase the size of colonies. However, the primary means of dispersal of this species to new areas is via the dumping of pieces of the underground stems (i.e. rhizome segments) in garden waste, so care must be taken with its disposal.

For manual removal, carefully dig out isolated plants and small infestations, making sure that all fragments of the substantial rhizome system are removed. This requires persistent effort and very regular monitoring of the site and removal of any new growth and its rhizome. To prevent reshooting, all plant pieces should be put into strong bags and removed from bushland.  Alternatively, you can place plant parts in a sealed black plastic bag, and leave in the sun for a week to kill it.

Mother in Law’s tongue is a declared pest plant on Fraser Island under the Fraser Coast Regional Council Local Law No. 3 (Community and Environment Management) 2011 and Subordinate Local Law No. 3 (Community and Environment Management) 2011. All landowners on land under their management are legally responsible for controlling pest plants on their property with an obligation to eradicate where possible, prevent the spread of and reduce the existing size of infestations.


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