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Angled Onion small groupA familiar sight (and odour) around the Dandenong Ranges in mid-winter to early spring is the appearance of the weed Allium triquetrum, common name Angled Onion.

It is often called onion weed due to it’s strong accompanying odour of onions, but technically this is incorrect, although it is known officially by this name in New Zealand.

Part of the lily family, it is a native of the Mediterranean but has managed to thrive in the Dandenongs thanks to the abundance of damp semi shaded areas along stream banks, roadsides and bushlands.

Angled Onion is considered an environmental weed because it smothers and displaces indigenous grasses and groundcovers impacting the processes of bush regeneration.

Description: A green three cornered flower stalk with a white trumpet shaped flower at the top of each stalk which grows in clumps.

Dispersal: It spreads in two ways - seed dispersal from the white flowers and bulb reproduction below ground.

Treatment: Knowledge of the life cycle is the easiest way to understand the best ways to treat Angled Onion.

Green shoots grow from food stored in bulbs underground which in turn allow the formation of seed producing flowers. Interrupting the process by which the seeds are formed is the most effective strategy.

Life Cycle Angled OnionSlashing:  Cutting the green shoots as soon as they appear above ground will start to exhaust the bulbs and slow down the growth cycle.  Repeated slashing will exhaust the reserves in the bulb so that it is unable to keep producing shoots and eventually flowers. Adding dense mulch will also help. It can sometimes take several seasons to finally achieve success.

Hand Removal:  While the ground is moist in winter this can be effective although time consuming. By the time the flowers have appeared, the bulbs have reproduced under the ground so that hand removal becomes largely ineffective as many smaller bulbs may be left behind.

Spraying:  Spraying with a glyphosate based product is best done just prior to or when the flowers are formed. This targets the seeds and stops them being distributed.

Summer Collection:  Oddly enough, removing Angled Onion bulbs is possible over the summer months. As the surface ground dries out, the bulbs become visible just below the surface and can be collected.

Biological Control is also a future method of control:  https://link.springer.com/article/10.1007/s13313-014-0279-6

 

Wild Tree Tobacco (Solanum mauritianum)Wild Tree Tobacco (Solanum mauritianum) is an emerging very invasive weed we now seeing in the Dandenong Ranges.

It forms dense stands gardens or forest areas and roadsides competing with other trees and shrubs.

It is found along creeks and can spread through most forest types.

All parts of the plant are toxic.

Wild Tree Tobacco grows 3 to 4m high as an open branched large shrub or small tree.

Leaves are up to 30cm in size large, grey-green with soft hairs and a distinctive pungent smell.

Produces clusters of violet coloured flowers all year that change to orange berries, which are readily spread by birds, animals and human activity.Wild Tree Tobacco (Solanum mauritianum)

Hand-pull as small plants or cut and paint stems of larger ones with herbicide.

For more advice see Yarra Ranges Council web page at www.yarraranges.vic.gov.au/Property/Trees-vegetation/Weeds

 

Monbretia (Crocosmia Crocosmiiflora)Monbretia invades gardens, bushland, roadside areas and streamsides. It grows well in all conditions. It is a vigorous, perennial herb appearing in spring and dying back in autumn. 

Monbretia can take over an area and displace indigenous grasses, groundcovers and other plants.

Pictures show flat, strap leaves (between 30 to 80cm long) photo taken in November, and orange flowers that appear in December.

The leaves grow from underground bulbs. There are often many bulbs found together.Monbretia (Crocosmia Crocosmiiflora)

It was a popular garden plant due to its bright orange trumpet-shaped flowers, which form in two rows along each stem.

Treatment time December to April, by hand-weeding and herbicide. If hand-weeding, loosen soil underneath plant and remove the bulbs if possible.

A good way to treat it is to wipe each side of the leaves with neat glycophosphate.

For more advice see Yarra Ranges Council web page at www.yarraranges.vic.gov.au/Property/Trees-vegetation/WeedsMonbretia (Crocosmia Crocosmiiflora)