Bulbil Watsonia

Bulbil Watsonia

Watsonia meriana

Origin: South Africa
Size: 0.5-2m H, 0.5-1.5m W
Best removal time: September
Flowers: September to December
Fruits: October to December

What it does

Invades gardens, bushland and roadside areas where slashing and maintenance help to spread the bulbils. Tolerates full sun, moist areas, shady and windy conditions. Takes over and displaces indigenous grasses and groundcovers.

Bulbil Watsonia is a declared Noxious weed across Victoria as it has the potential to spread widely and cause serious economic loss to agriculture or have some detrimental effect upon people, animals, the environment or the local community

What it looks like

The leaves are rigid, straight and sword-shaped with a prominent mid-vein which is up to 80cm long. The flower spikes can stand up to 2m and they bear two rows of dull orange, curved tubular flowers. The lower part of the flower spike carries clusters of bulbils.

How it spreads

Watsonia reproduces mainly by producing new corms (a corm is an underground swollen stem that forms the base of the plant) and by dropping the bulbils (inset, left) from the flower spike.

Each bulbil then grows into a new plant. Plants die back to the corm and reshoot each winter. Corms and bulbils spread:

  • through water and contaminated soil
  • via dumped garden waste
  • is sold at markets and fetes. Buyer beware!


Remove by Hand

Easiest for small clumps. Larger areas can be forked when the soil is quite moist. Follow up is necessary to remove all corms. Most effective just before flowering.

Dig out

Dig out patches of Watsonia. You will need to ensure all corms are removed and take care not to drop bulbils as the plant is disturbed. If the soil is moist this is best done using a garden fork. It is important to avoid dumping the soil elsewhere.

Spray with herbicide

Watsonia can be sprayed, or leaves swiped with a glyphosate-based product. The most effective time is just before full flowering which occurs in spring.

Indigenous alternatives to plant

Many lily and iris alternatives exist that are indigenous to the Yarra Ranges region and would make great substitutes for the Bulbil Watsonia. Some alternatives include:

Spiny Mat Rush, Lomandra longifolia

Butterfly Flag, Diplarrena moraea

How to dispose of weeds

By disposing of environmental weeds correctly you can prevent re-infestation on your property and elsewhere.

  • Landfill (Weed Wipeout Tip vouchers available for some species).
  • Green waste bins ensure that weeds are not able to spread.
  • Woody weed stems can be bundled for green collection twice per annum.
  • Composting (excluding seed heads or species with vegetative reproduction, e.g. Wandering Trad).
  • Burning in accordance with Council and the Country Fire Authority (CFA) prescribed burning periods and regulations.
  • Recovery and transfer stations available for weed tipping are Healesville, Wesburn, Coldstream, Lysterfield and Montrose.

Using chemicals

Non-chemical treatment is often the most effective and safe option especially on smaller scale infestations.

Where chemical use is undertaken:

  • Always follow the manufacturer’s guidelines when using chemicals.
  • Wear protective clothing and eyewear.
  • When purchasing your herbicide, always ask for a Materials Safety Data Sheet (MSDS) or refer to the manufacturer’s website for specific safety guidelines and information.
  • Some herbicides will kill other plants and not just the target species.
  • When used near waterways herbicides can be very poisonous to aquatic life.
  • Use chemicals sparingly and be sure that you are using the right chemical and application technique.
  • Ensure the weather conditions are suitable (e.g. minimal wind and no rain expected).
  • Apply herbicides at the correct time during the plant’s growth cycle so you get the best results.