Quick Facts

Quick facts

• Garden geranium (Perlargonium alchemilloides) is a low-growing), long-lived, herbaceous plant usually about 20 cm tall.
• It originated as a garden plant from Africa that is now invading indigenous bushland and has the potential to threaten agriculture.
• It is currently known to be naturalised in only one small area in south-western Western Australia but is considered to have the potential to invade much of southern Australia.
• It is a prolific seeder and can also spread vegetatively from tubers and stem pieces.
• It is able to invade disturbed areas and survive hot dry conditions.
• Any new naturalised occurrences should be reported to the relevant weed management agencies.

What Does It Look Like?

What is it?

Garden Geranium (Pelargonium alchemilloides) is a very widespread species in South Africa and is quite variable from location to location (CRC 2003b). It is a straggling perennial herb, usually about. 200 mm high, with spreading stems arising from a woody tuberous or stoloniferous rootstock (Van der Walt 1977).

The stems are covered with long, coarse hairs and are produced from a central rosette of leaves (CRC 2003).

The flowering branches produce flowers in clusters of three to six, sometimes up to 15, from the tip of the branch (Van der Walt 1977). Leaves are two to seven cm in diameter, five to seven lobed to at least half way to the base and the lobes are irregularly toothed (Germishuizen 1997). The leaves have a silky appearance due to a dense covering of hairs and some have a purple, brown or dark red horseshoe-shaped zone (Van der Walt 1977).

Flower colour is usually white, cream or pink. White or cream flowers occasionally have pink or red markings (Van der Walt 1977). Pale yellow flowers have also been reported (CRC 2003b). Flower size is quite variable. The petals range from 10 – 20 mm long and 2 – 10 mm wide (Cullen et al. 1997). The showiest forms have quite large white or deep pink flowers and often have silvery leaves (CRC 2003b).

Fruit is a distinctive pod shaped like a crane’s bill. A single plant will die out after a few years, but will easily re-establish new individuals because it is a prolific seed producer (NSW Weedwise 2020).

For further information and assistance with identification of Garden Geranium contact the herbarium in your state or territory.

Flower colour

White, Pink, or Yellow

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

In South Africa, Garden Geranium occurs in grassland (Germishuzen 1997) and disturbed areas (Pooley 1998) across a wide area with a climate ranging from Mediterranean in the southwest to temperate in the interior plateau and subtropical in the northeast (Victorian Department of Primary Industries).

It is believed that the southwest form is present in Australia and is highly adaptable to the climate of southern Australia (CRC 2003a).

At the Hamelin Bay site it has invaded low Agonis flexuosa (peppermint) woodland on sandy coastal soil (CRC 2003a). The first collection was made from low dunes in grey sand over sand (specimen data from WA Herbarium, June 2007).

The average annual rainfall for Hamelin Bay is 1000mm (CRC 2003a).

Are there similar species?

Garden Geranium is not known to be mistaken for other species at this stage. It has potential to be confused with some indigenous and introduced Geranium and Pelargonium species.

Why Is It A Weed?

What are its impacts?

Garden Geranium is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia's ecosystems (CRC 2003a).

Native ecosystems: The current impacts of Garden Geranium in Australia are on environmental and biodiversity values. It has invaded intact indigenous vegetation and threatens to outcompete understorey plant species and associated fauna at the Hamelin Bay site. It is considered to have the potential to have these kinds of impacts over a considerable area of southern Australia. It is also assessed as having the potential to impact negatively on agricultural production because it can colonise disturbed sites, seed prolifically and survive harsh conditions (CRC 2003a).

How does it spread?

Garden Geranium is a prolific seed producer and can also be propagated by stem and tuber cuttings. The tuberous rootstock enables it to survive harsh dry periods and times when seed production is not successful.

The seeds can remain viable in the soil-stored seedbank for a long period of time due to the presence of chemical inhibitors that prevent all seeds germinating at the same time. Soil disturbance is thought to have been the major cause of the recent population increase in Garden Geranium at the Hamelin Bay site, as the rate of spread was slow until roadwork's using graders and trucks occurred. Seeds germinate and pieces of underground stem grow into new plants when soil is disturbed (CRC 2003a).

What is its history in Australia?

Garden Geranium was originally introduced to south-western Western Australia when planted in gardens. It has been estimated that initial introduction to the Hamelin Bay area took place in the early 20th century when a timber settlement occurred there (CRC 2003a). This plant is often found growing in disturbed areas (Van der Walt 1977).

The first naturalised collection of Garden Geranium from the Hamelin Bay site was made in January 1988, at which time it was described as abundant (specimen data from WA Herbarium, June 2007).

How To Manage It?

Best practice management

Because it is currently known from only one site there is potential to eradicate Garden Geranium. An eradication program is currently being negotiated between relevant land managers in the district where the infestation occurs (CRC 2003a). If other infestations are discovered they should be reported to the relevant state or territory weed management agency and specimens should be lodged at the relevant state or territory herbarium for formal confirmation of identification.

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

The main flowering period is in spring following the April-August regrowth period but some flowers may be found throughout the year (CRC 2003; Van der Walt 1977).

Garden Geranium belongs to a group of tuberous pelargoniums that survive hot dry conditions by undergoing a period of dormancy following seed production and dispersal (CRC 2003a and 2003b). In horticulture, it has been observed to grow all year if given water continuously (CRC 2003b). Seed germination and subsequent growth is generally in late autumn and winter but it can be erratic and take place over a long period (CRC 2003a). Plants tend to die after a few years but re-establish readily from soil-stored seed (CRC 2003b).

Where Is It Found?

Which states and territories is it found?

WA

What areas within states and territories is it found?

At present, Garden Geranium is very localised in south-western Western Australia. It is known from one site along a roadside two km east of Hamelin Bay where it has invaded adjacent vegetation. It is currently distributed patchily across an area of approximately 10 hectares (CRC 2003a).

Climate and soils suitable for Garden Geranium are found in much of southern and central Australia including parts of all southern states, from semi-arid to temperate pastoral country on sandy coast soils (CRC 2003a).

Where does it originate?

Garden Geranium occurs in grassland throughout southern Africa, extending northwards through tropical Africa into Ethiopia and Somalia (Germishuzen 1997).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

Not declared in any Australian state or territory

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

YES

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

Pelargonium alchemilloides

Other scientific names (synonyms)?

Geranium alchemilloides L.

Does it have other known common name(s)?

Pelargonium, Lady's Mantle-leaved Pelargonium, Pink Trailing Pelargonium, Wilde Malva