Blue Star Spreading In Horton Plains

l by Dr. Lalith Gunasekera

(December 01, Melbourne, Sri Lanka Guardian) My recent visit to Horton Plains gave me an immense pleasure as well as big headache as I recognised large amount of invaders within this beautiful land mass. Blue star botanically named ARISTEA ECKLONII is a small, rhizomatous perennial plant originated in Uganda, Cameroon, Rwanda and South African region. It appears to be restricted to cooler highland habitats. It is a popular garden ornamental around the world where it is grown for its attractive blue flowers. It was introduced to Hakgala Botanical gardens in 1889 as an ornamental plant and slowly it has escaped from the garden to cooler Horton Plains and surrounding area. Blue star plant has been invading the Horton Plains grasslands, roadsides, along water ways and wetlands. It has formed dense stands over small areas and is still spreading. They invade and compete with endemic grasses, herbs for nutrients, water, light and space. Dense infestation of blue star completely smothered important food sources such as small herbs, shrubs and native grasses used by native animals.

Features of the plant

• Blue star belongs to Iridaceae plant family. It is a spreading, evergreen, rhizomatous perennial with stiff upright grass like leaves.

• It grows 30-70 cm tall in a tight clump

• Flowering stalks become covered with dozens of small, blue, saucer shaped flowers standing above the leaves.

• Each flower lasts for one day and only opens in bright light.

• After pollination they produced small cylindrical fruits, 20mm long and containing large amount of seeds. Seeds are very small 1.5 mm long.

• Blue star plants spread primarily from seeds which are produced in abundance. However it can also be propagated by dividing rhizomes, tubers, corns or bulbs.

• Seeds are reported to be dispersed by water, wind and animals.

• This plant is listed as a weed in New Zealand, Australia (Victoria) where it grows in extensive patches within native vegetation along roadsides, stream banks and in open forests.

• In Sri Lanka, we have to keep an eye on this plant’s behaviour and also very important to recognised this as an invasive species in Montane zone such as Horton Plain region.