Quick Facts

Quick facts

  • Originally from South Africa, Agapanthus (Agapanthus spp.), is an erect perennial evergreen herb with a stout underground rhizome (stem) with clusters of  20-40 blue, purple or white showy flowers held together on top of a flowering stem.
  • It is a very common hardy horticultural plant that spread from gardens to mostly native vegetation in cool to warm temperate areas.
  • Reproduction is vegetatively by rhizomes and by seed.
  • Initial spread is normally by dumping of garden material or  seed with established clumps spreading via underground vegetative suckering of rhizomes producing new plants expanding patches dominance over time.
  • The rhizomatous roots clump and crowd out other vegetation.
  • Removal is best done manually, as herbicide treatment is not very effective.

What Does It Look Like?

What is it?

Agapanthus (A. praecox subsp. orientalis, A. praecox subsp. praecox and A. praecox subsp. minimus ) is an erect perennial evergreen herb with a stout underground rhizome (underground rooting stem), with stem-like flowering stems to about 1.2 – 1.5 metres tall, forming large clumps over time. The leaves that arise from the root, ; clustered at base of stem-like flowering stem.  Leaves are strap-like, glossy dark green, 400-800 mm long, 30–50 mm wide.  Leaves when broken exude a gelatinous substance.

It has blue purple or white flowers are held at the top of robust, hollow, erect smooth stem in umbels (large dense heads of spherical clusters ) each containing 20-40 flowers, 100–200 mm in diameter. Each flower is on an individual flower stalk (pedicels) 50-80  mm long. Flowers are funnel-shaped, to about 40 mm long, fused into a tube (15-20 mm long) at the base, with 6 tepals (petals). Most flowering occurs from November to February but flowers can be seen at other times of the year as well.

The fruit is leathery green three-sided capsules about  25–50 mm long which dries to pale brown splitting open, containing 20-100 black seeds that have a wing-like projection.

Recognition: This species can normally be recognised by the combination of the following characters; thick underground rhizomes that produce new plants, evergreen herb with strap-like shiny glossy leaves too 800 m long and 50 mm wide;  Flowers 20-40 in spherical clusters that are large trumpet -like flowers to 80 mm long, normally blue or purple  or white; produces a 3 sided capsule green at first drying pale brown splitting open, with black winged seeds.

Dwarf forms are sold, which are identical to the typical form, but smaller (Eurobodalla Shire Council undated). For further information and assistance with identification of Agapanthus contact the herbarium in your state or territory.

Flower colour

Blue, Purple or White.

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Sunny situations are preferred, but Agapanthus will invade forest edges and open forest. It tolerates a wide range of conditions from damp to very dry (Eurobodalla Shire Council undated; Shire of Yarra Ranges undated). It is known to form dense monocultures in temperate areas in South Australia under native and introduced tree species.

Are there similar species?

Agapanthus can be confused with the native ground cover, Commelina or Scurvy Weed (Commelina cyanea). Commelina can be identified by its blue flowers and thick, fleshy roots. Nerine Lilies, another garden plant, are similar in form, but much less robust.

The native tussock plant Spiny Mat-rush (Lomandra longifolia) could possibly be mistaken for Agapanthus if neither plant was in flower, or carrying the remains of flowers. It has similar bright green strap-like leaves, but they are less fleshy than those of Agapanthus, and each leaf typically has a squared tip with 1-3 small teeth (Eurobodalla Shire Council undated; Pittwater Council undated).

Why Is It A Weed?

What are its impacts?

Agapanthus invades gardens, bushland and roadside areas, and can also invade pastures. It tolerates a wide range of conditions from damp to very dry and takes over and displaces indigenous grasses and ground-covers in the temperate regions of southern Australia.

Agriculture: Agapanthus is not known to be a serious weed of agriculture or other primary industries but has been recorded invading pastures spreading from nearby gardens. The leaves and roots are poisonous and can cause ulceration of the mouth.

Native ecosystems: Agapanthus invades bushland and roadside vegetation. It forms dense stands, where its dense clumping roots displace all other vegetation and smother native ground-covers, prevent regeneration of trees and shrubs, and eliminate habitat for native fauna. It has been promoted as a fire-resistant plant for residential gardens in fire-prone areas since the lush clumps are likely to be very fire retardant (ACTPLA 2005). However, it could also have an impact on fire frequency in native vegetation, making infested bush difficult to burn. 

Urban areas: Agapanthus invades gardens and can spread vegetatively over many years, also slowly spreading along roadsides. It attracts large numbers of snails and slugs (Eurobodalla Shire Council 2020; Shire of Yarra Ranges undated; WBMB undated).

How does it spread?

Agapanthus reproduces via seed, and vegetatively by underground rhizome (underground rooting stem) and by dumping of material.

The large numbers of tiny seeds are also easily transported by soil movement, wind, waterways, and by dumping garden waste in bushland areas. It is commonly sold at markets, nurseries, fetes and club fundraisers (Shire of Yarra Ranges undated; WBMB undated).

It can also reproduce vegetatively via its short creeping underground rhizome (underground rooting stem), and can give rise to new individuals, forming large continually extending clumps. However, clumps are most commonly spread to natural areas in dumped garden waste and in contaminated soil and seeds may also be spread in this way too.

What is its history in Australia?

The history of the introduction of Agapanthus into Australia is unknown. It was presumably introduced as a garden ornamental with the first wild collection made in 1973 from South Australia in a conservation park on the edge of suburban Adelaide. 

How To Manage It?

Best practice management

The most effective control method for Agapanthus is physical removal of plant and underground stems (rhizomes). Herbicides are not normally an effective control option  for this environmental weed.

Chemical control: Agapanthus is quite resistant to herbicides. Surfactants may help improve penetration into the wax-coated leaves (Eurobodalla Shire Council undated). Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au.

Non-Chemical control: Physical control, infestations of Agapanthus can be dug out or pulled out as the rhizome is shallowly rooted. Plants can be peeled over to one side and up-ended with less effort than might be expected. However, all of the rhizome must be removed and destroyed off-site, as any rhizome left in the ground will regrow. Plants left lying on the soil surface may take root again, even if turned upside down.

Biological control: No biological control options are available.

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Deciduous members of Agapanthus (those that die back to the bulb each year) begin their growth cycle with spring rains, resulting in rapid vegetative growth and culminating with flowers in the middle of summer.

The evergreen Agapanthus that are weedy in Australia will shed a few older leaves annually and will flower for a longer period, often beginning in late spring and only ending as the temperatures fall in autumn (Royal Horticultural Society 2006). It actively grows in spring when warmer conditions and water is available but can grow year round, growth slowing in very hot or cold conditions.

Where Is It Found?

Which states and territories is it found?

NSW, SA, TAS, VIC, WA

What areas within states and territories is it found?

Agapanthus is emerging as a potential weed threat in parts of New South Wales, South Australia, Victoria and Western Australia because of its hardiness and drought resistance. It is recorded as doubtfully naturalised in Tasmania. In the Blue Mountains in New South Wales, the ledges below the Three Sisters lookout are full of Agapanthus, in place of the native flora (McFadyen 2005). It is becoming more common as a weed in higher rainfall areas of South Australia both in shade under trees and in full sun on roadsides.

Where does it originate?

Agapanthus is a native of South Africa (WBMB undated).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

Not declared in any states and territories in Australia

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Agapanthus spp.

Other scientific names (synonyms)?

 

Does it have other known common name(s)?

African Lily, Lily of the Nile.

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