Weeds of the Cooks River Valley

The Mudcrabs currently work on 15 sites along the Cooks River. Many of these are bush regeneration sites. Regeneration usually involves 3 primary activities for our volunteers. Depending on the site these are:
Landscaping – terracing and major site preparation (includes habitat/critter piles)
Planting native species – selection and timing are important
Weeding – an on-going process that encourages site regeneration

Weeding is the primary activity that The Mudcrabs volunteers are involved with. It is through targeted weeding that we allow space for the native plantings and remnant natives species to re-establish and develop an ecosystem that reflects the original state of the bushland that was the Cooks River Valley. A number of sites have a weed pile that allows the weed material to compost and is a great way to recycle the weeds back into the site.

Identification of priority weeds and applying the right strategy will yield the best results. This webpage is designed to help new-comers to bush regeneration understand what we do on the various sites and how they can help. Gaining skills in weed identification is an important capability for our volunteers. Most of our bushcare activities start off with an identification of what weeds we will target for the session and what techniques we will employ to remove these weeds.

Our experienced botanists and bush regenerators have put together a list of the weeds that we target across our Cooks River sites. Being able to identify these weeds and understanding how to eliminate/manage them really helps in re-establishing healthy native zones that support and encourage the return of original ecosystems.
Note that we have a couple of native species in this list. In our area they can prove a pest if they end up in the wrong place.

Below is a table of the main weed targets. The ones we target in a session are determined by how numerous/obvious they are and how soon they are to throwing seed or replicating. Some weeds (annuals) have a short life-cycle (seed, grow, drop seeds, die) e.g. Ehrharta, others are are long-lived (perennial) and reproduce continuously e.g. Lovegrass,Trad.

In our weed table we have selected the top 67 weed species and have assigned a ‘Significance value’ to each one:
1 – means a focus weed that we remove whenever we encounter it
2 – means that we consider whether the infestation warrants the effort of removal
3 – means that the weed is relatively uncommon in the Cooks River Valley but worth removing when we encounter it.

Common NameScientific NameSignificance
Turkey RhubarbAcetosa sagittata1
Crofton WeedAgeratina adenophora1
Madeira VineAnredera cordifolia1
Moth VineAraujia sericiflora1
Balloon VineCardiospermum grandiflora1
CeltisCeltis australis1
Green CestrumCestrum parqui1
Camphor LaurelCinnamomum camphora1
African/Weeping Love-grassEragrostis curvula1
Seaside DaisyErigeron karvinskianus1
Cockspur Coral TreeErythrina crista-galli1
Coral TreeErythrina X sykesii1
Yellow Ginger LilyFiedychium gardnerianum1
Honey LocustGleditsia triacanthos1
English IvyHedera helix1
Kurnell Curse/PennywortHydrocotyle bonariensis1
Coastal Morning GloryIpomoea cairica1
Blue Morning GloryIpomoea indica1
LantanaLantana camara1
Large-leaved PrivetLigustrum lucidum1
Small-leaved PrivetLigustrum sinense1
HoneysuckleLonicera japonica1
Primrose WillowLudwigia peruviana1
Mickey Mouse PlantOchna serrulata1
African OliveOlea europaea ssp. africana1
Asthma WeedParietaria judaica1
KikuyuPennisetum clandestinum1
African Fountain grassPennisetum setaceum1
Asparagus FernProtasparagus aethiopicus1
BlackberryRubus fruticosus spp.1
Chinese TallowSapium sebiferum1
CassiaSenna pendula var. glabrata1
Paddy’s Lucerne Sida rhombifolia1
Potato VineSolanum jasminoides1
RhusToxicodendron succadenaneum1
TradTradescantia albiflora1
Golden Wreath WattleAcacia saligna2
Box ElderAcer negundo2
Giant ReedArundo donax2
Carpet GrassAxonopus affinis2
Common CouchCynodon dactylon2
Panic VeldtgrassEhrharta erecta2
Lemon-scented GumEucalyptus citriodora2
Fishbone FernNephrolepis cordifolia2
Climbing AsparagusProtasparagus plumosus2
Black-berry NightshadeSolanum nigrum2
Sow ThistleSonchus oleraceus2
Buffalo GrassStenotaphrum secundatum2
Mist-flowerAgeratina riparia3
Tree of HeavenAilanthus altissima3
Whisky GrassAndropogon virginicus3
Mother-of-millionsBryophyllum delagoense3
Live PlantBryophyllum pinnatum3
Cabomba, FanwortCabomba caroliniana3
Flick WeedCardamine hirsuta3
Ribbon Plant, Spider PlantChlorophytum comosum3
Pampas GrassCortaderia selloana3
Cape IvyDelairea odorata3
Silky OakGrevillea robusta3
JasmineJasminum polyanthum3
Baby SmilaxMyrsiphyllum asparagoides3
Japanese KnotweedPersicaria capitata3
Canary Island PalmPhoenix canariensis3
Lippia, Carpet WeedPhyla nodiflora3
PolygalaPolygala myrtifolia3
Black LocustRobinia pseudoacacia3
Blue PeriwinkleVinca major3
Cooks River Valley Weeds

Weeds & Removal Strategy

Most of these weeds can largely be managed via hand weeding. We try to get to them before they throw seed. As many are annuals, we can interrupt the seeding cycle and significantly reduce their impact and give the native plants an advantage. The technique used is species specific so identification is crucial.

Kikuyu is a particularly challenging weed along the river as it is very vigorous and spreads quickly in optimal conditions by underground stems (rhizomes) and over other plants via its robust aboveground stems (solons). This persistent weed species continues to be the main focus at many of our Mudcrabs sites along the Cooks River. The primary technique is to trace the aboveground stolons back to the crown and remove them. The underground rhizomes can be “chased” using a knife or your preferred weeding tool and pulled out. For larger, dense infestations we rob the weed of sunlight (solarisation) by cardboard and mulch. The cardboard decomposes in a few months and we can infill with native plants.

Below are pictures of Kikuyu from the 18th Tee Mudcrabs site. We have used ‘solarisation’ on larger areas (cardboard and mulch) and hand weeding to remove it. When we encounter Kikuyu we expect to have multiple sessions to get it under control.

Understanding how weeds spread guides us in adopting the appropriate management strategy. Since Kikuyu spreads from both above ground and below ground stems we need to remove these.

Weeding References

Native and Weed Look A-likes – Hornsby Council
Common Riverbank Weeds – Greater Sydney
Sydney Weeds Network
Bushland Weeds of Sydney – AABR