Linda and Roger's Bunhybee Grasslands

Weed Control Plan

This is a page within Roger and Linda's Bunhybee Grasslands Web-Site.
Bunhybee Grasslands is a 49 hectare / 120 acre conservation property 35km south of Braidwood, in southern N.S.W.
You can follow through the internal links, or you may find it easier to use the Site-Map.

This is a subsidiary page to the Action Plan. It contains our plans on how to tackle each category of weed on the property. It draws on various sources, including our own experience.

Some guidance is in the Management Plan (2.7 pp. 26-27, App. B p. 41, App. F p. 52 – a DPI brochure, App G p. 53). We have also drawn on a variety of Weed Management Resources.

The weeds that have been identified on the property are catalogued here:

Here is a map of the weed infestations when we took possession at the end of 2008.

The weeds for which we have control plans in place are as follows. They are in roughly descending order of concern:

Progress against this Plan is reported in the separate page on Weed Control Implementation.

Serrated Tussock (Nassella trichotoma)

For photos, go to the Bega Valley Plant Index, and key Nassella trichotoma into their search-engine.

1. Identification

Four foreground,
six middle-ground
Serrated Tussocks
appear dark and tight
Six clearly visible here
A patch of nearby Stipa
Click on any image ...
... to see a larger version
...
The plumes of the nearby Stipa
...
Left, Right in each photo ...
... the Serrated Tussock, and the Stipa
The darker image of Serrated Tussock
4 Serrated Tussock,
diagonally up the right

2. Attack Timing

To avoid seed-dispersal, the preferred times are:

You may have to attack in mid-summer (in the Southern Tablelands, variously late November to early January), in order to ensure reliable identification (or because that's the first time you notice it!).

3. Attack Method

Our treatment in mid-summer (roughly, mid-December to February)
Seed-heads are already well-developed, for easy recognition, but with high risk of seed-dispersion

Our treatment at any other time of year
The seed is forming, enabling confident identification, with limited risk of dispersion of viable seed

Our treatment at other times of year
If we're confident in our identification, we remove them, as immediately above.
If not, we mark it down for re-inspection in early summer.

Alternative treatment is:

4. Herbicide Choices include:

Herbicide Mixes of various kinds are recommended by various sources. They include:

5. Sources

Blackberry (Rubus fruticosus spp. agg.)

Recognition is easy.

Distinguishing it from the multiple native Rubus species is also reasonably easy, most commonly Native Raspberry (R. parvifolius). The natives have smaller leaves and less prominent fruit, and their leaves seem to darken a lot less over the winter. And, on top of that, we've found none on the property.

Blackberry is an eternal weed, because of continual re-infestation from nearby properties mainly transmitted by bird-poo. Blackberry grows very rapidly, trails across to establish new roots 1-3 metres away, and re-grows vigorously from existing roots. Because large bushes are a great deal of hard work, early action on new bushes is vital.

On large properties, and with large infestations, spraying and raking may be necessary. See the Blackberry Control Manual.

But we had the advantage of relatively small areas of infestation (1 x 20 sq.m., a dozen 2-5 sq.m., and a couple of score 1 sq.m. bushes), and have adopted a different approach on Bunhybee.

We use a variant of cut-and-paint, using glyphosate, which is described immediately below. (See the generic description of Cut-and-Paint). It's labour-intensive (indicative 6-10 sq.m. in a 2-person 5hr-day). But it is very effective, and can even achieve one-round knock-down.

Timing:

The Preparatory Attack:

The Attack Proper:

Black/Spear/Scotch Thistle (Cirsium vulgare)

This is a biennial, which grows a rosette in its first year, and a stem in its second. It can produce large numbers of buds, each of which contains large numbers of seeds (c. 50?), which float clear of the dying flower and mostly fall close by. The species is cunning in that it typically has one early flower, followed by a succession over the summer and autumn. Green buds and the bowls beneath the purple flowers contain seeds; but old, open heads have probably already released them. The plant appears to reliably expire after its one season of fruiting:
Mature, unopened heads
... showing viable seed ...
... still inside
Old heads, after releasing seed

We've come across the theory that thistles can, in some circumstances, act as valuable colonisers and soil-improvers, and may be transitory (although for some years). None of the areas where we've found them need soil-enrichment; so in all cases we've treated them as weeds needing removal.

We've mainly worked out the following treatment methods for ourselves, but an excellent US Forest Service source that we've found since has confirmed most of our thinking.

Rule 1 is that good, thick gloves are essential, preferably gauntlets, i.e. with lower-arm protection.

If the plant is in its second year and has a stem

There may already be viable seed even at the time flowering begins.
Our preferred timing for the attack is December-January
The plant needs to be removed, because, until as late as the end of summer, the species is highly resilient, and is capable of forming many further buds, even on a chopped stem.

  1. Clip off all flowers and green heads, place them carefully in a bag, then seal-and-leave (best done in a black bag, to maximise the heat), or remove-and-incinerate.
  2. Destroy the remaining plant. Alternatives include (best first):

If the plant is in its first year and still just a rosette

Alternatives include (best first):

If the plant is aged and all heads are open

There might be seed left, but mostly it will have flown.
Pulling the stalk out is more of an aesthetic matter than a weed management measure; but we tend to pull them

Other Thistles:

Nodding Thistle (Carduus nutans)

Nodding Thistle (Carduus tenuiflorus)

Common Sow-Thistle (Sonchus oleraceus)

At this stage, we've treated the few that we've found the same as Cirsium vulgare. See above

What's this one?

Yorkshire Fog (Holcus lanatus)

We've yet to locate any resources at all that actually help with ideas on management of this weed-species!

Here's a 1994 paper, from Stillwater on the Collecter-Goulburn Road.

Sweet Vernal Grass (Anthoxanthum odoratum)

This was in a very limited numbers until the drought broke after 2009.
It's emerged in larger numbers, in various places, sometimes clumped.
It looks liable to spread further if conditions are right for it.

We've experimented with early-summer (second-half-of-Nov) glyphosate-spraying.
It appears to have had some success, but with some collateral damage, .

The WA page is useful.
The roots become extended 'rhizomes', with a form like that of ginger.

One site advises:

Phalaris (Phalaris aquatica)

We're trying two alternative approaches:

Briar Rose / Sweet Briar (Rosa rubiginosa)

This seldom seems problematical, but it's a Class 4 weed under the NSW Noxious Weeds Act 1993, and has to be attacked.
We did it opportunistically 2008-12, but less successfully than we'd hoped, with moderate re-growth from root-stock.
(And the NSW DPI document does say that re-growth can occur over a period of years):

The NSW DPI document offers two approaches (but written for farmers, rather than conservationists):

Preferred – Foliar Spray (i.e. on leaves):

This is inappropriate at Bunhybee, because of collateral damage, and limited foliage on young plants.

Spray the whole bush thoroughly, but only when:
• the plant is in full leaf, and prior to leaf fall
• the plant is actively growing
• soil moisture is adequate
so preferably late spring to early summer (Sep-Oct); less good is the end of summer (Mar).

Start at the top of the bush and work down to the base
Treat seedlings and suckers around the drip zone of the plant.
Use glyphosate – 1.5–2.0 L in 100 L of water, and a higher rate on bushes over 1.5 m high (DPI 2011, p.74)

This has an inevitable drip factor onto plants beneath, so in some circumstances it's inadvisable.

Second-Best – Basal Bark Treatment:

We'll try this, to see if it's more effective at killing the roots than cut-and-paint.

Spray, with [surfactant], around the complete base of every stem, 0-35cm above the ground.
Ensure that stems and bark are not wet at the time of application as water will repel the mixture.
Only apply at times of year when plants are actively growing, i.e. not mid-summer, and the bark must be dry.

Flaxleaf Fleabane (Conyza bonariensis). Possibly also Tall Fleabane (C. albida / sumatrensis)

Here are additional photos at the Bega Valley Plant Index.

The descriptions on the ag pages are mostly of limited use to conservations.
The one from Qld is the most useful. See also the one from WA.

It looks like an annual, but in fact it's a perennial, the root-stock grows during winter, and throws increasing numbers of rosettes in spring, which grow into stalks as much as 1m to 2m. (C. bonariensis is meant to be only to 1m, and C. albida to 2m, so perhaps they're both present at Bunhybee and elsewhere in the Southern Tablelands, and perhaps they've hybridised).

A major flush of seedlings arises when significant rainfall events keep the soil surface moist for 3–4 days during germination, probably at any time in spring. Plants produce massive numbers of small seeds, and they survive on the ground-surface for at least one season.

Hand-pulling is the only really effective method, in order to get rid of the roots.

(Glyphosate spot-spraying is mostly ineffective. Some sources suggest spot-spraying of rosettes with Brush-Off at 10g per 100L water, in late winter / early spring; or a double-hit a week apart, with a different herbicide each time).

On Bunhybee, Fleabane has been mainly of nuisance value, except immediately after the drought broke, when we removed some hundreds. Our preferred attack timings are Sep-Oct and no later than Dec-Jan, when a big proportion of the seeds are becoming viable.

If none or few of the vast numbers of seeds appear viable:

(In most places at Bunhybee, the vegetation is thick enough to protect the disturbed ground, and the dirt is soft enough).

If the seeds look likely to be viable, then prior to the above:

Other Grasses

Apart from Serrated Tussock, we're only progressively getting to grips with the other introduced grasses. Initially, it was challenging to distinguish some of them from the many native grasses. And because introduced grasses are commonly inter-twined with native grasses, it's proving challenging to devise appropriate control techniques. The other grasses for which we are developing plans are:

Techniques that we're experimenting with are:

Other Flowering Plants

At this stage, we have no plans in relation to the other flowering species. One reason is that the native species are strong, and most other weeds are either seen only occasionally or present few problems. For example, flatweeds are early colonisers of broken ground, but appear to be swamped by natives as time goes by. We've not concerned ourselves with Dandelion (Taraxacum officinale), which is everywhere and appears to be fairly harmless anyway; nor with Scarlet Pimpernel (Anagallis arvensis).

We have some concerns about:

This is a page within the Bunhybee Grasslands Web-Site, home-page here, and site-map here
Contact: Linda or Roger
Created: 14 December 2008; Last Amended: 4 September 2013