RECOMMENDED INDIGENOUS PLANTING SCHEMES - WOODEND RIPARIAN AREAS

(Costings are approximate as at March 2009)

WEEDS

Riparian areas generally have good soil unless the soil has been modified by human activity. Due to good soil and moisture, indigenous plants grow rapidly but so too do many weeds. So weed control is more challenging than in many other areas. To minimize ongoing weed control problems, rolls of matting appear to offer the best results. The advantage is that they provide a continuous cover, so weeds can only appear by sharing the slits made for the plants or stakes. This is a problem, but having scattered individual mats makes for a mosaic of weeds in between the plants, which makes weeding or spot spraying very difficult. Rolls of recycled fibre 2.4 metres wide are now available and these would be ideal for fairly dense plantings over small areas (120 square metres per roll). In the past we have also had problems where we have used two widths of the rolls and the weeds appear in the area of the join. So a single width seems the best option. There is the possibility that any riparian area may flood occasionally, so planting schemes should take account of this. If rolls of weed control matting are used, they need to be firmly pinned down, especially at upstream edges. Consideration should also be given to using pins of greater than the standard 150mm length.

PLANTING TECHNIQUES

Where time permits, weed control needs to be undertaken at the planting site, ideally a full year ahead of planting. A final weed spray should be done shortly before planting. Any areas which are sprayed for weeds but not then covered with weed matting are certain to produce great numbers of weeds so this needs to be considered in the overall plan. One suggestion is to plant woody species (some trees and many shrubs) into the fibre roll area, all with 3 bamboo stakes and a plastic plant guard. The plant guards help protect the plants against spray drift and also help them grow upright. It is worth spending a little more to buy the 11-13mm bamboo stakes for plant guards rather than the fragile smaller diameters. Outside the fibre rolls, monocots (strappy plants) can then be planted without plant guards but with one stake each to mark their position. As the weeds emerge around these strappy plants, they can be carefully spot sprayed using a selective herbicide such as Garlon which will not kill the strappy plants but will kill most of the weeds. Unfortunately non-native grasses will survive so this method is far from perfect. But it may still be the best we can manage in our situation. Most understory plants can be planted at 1 metre centres. Tree species should be planted further apart and in general should be no closer than 3 metres apart. This is still too close for big trees, but it allows for the inevitable failures and runty plants.

We have found that Spring plantings are the most successful as there is usually some water left in the soil from the winter, especially near the creek. Some species do suffer from late frosts, especially if they are planted in the open. So October is probably the best month for planting. Over the last 5 years, the latest frost has been in mid-October although they can occur much later if we are unlucky. Plants need at least a litre of water each immediately after planting. If there is no rain in the next week or two, further watering may be needed. There will be less need for follow up watering close to the creek. In general, plantings near the creek have a survival rate of about 90% which drops to as low as 50% in drier and harder sites. If using rolls of weed matting, recycled fibre is slightly better than jute in that it allows rainfall to soak through more easily. The weed matting should rot away in a few years. The pins in the matting will also rust away. The plant guards can be removed at an appropriate time.

PLANT SPECIES

Plants of the right species grown on or near creek banks can grow very fast. There is a marked reduction in growth rate and survival rate further away from creeks and drains. The following are two lists of commonly planted species. One is for the wetter sites and one for the drier sites. Where possible, plants should be not just of the correct species, but they should be grown from locally collected seed. There are many reasons for "local provenance", but the obvious one is a much higher survival rate. Unfortunately seed collection is an art and the window of opportunity during which seed can be harvested is very short. So we have not always been able to source purely "Woodend" plants.

WET AREAS

TREES / SHRUBS / STRAPPIES
Euc. aggregata / Acacia dealbata / Carex appressa
Euc. viminalis / Leptospermum continentale / Poa lab.
Euc. ovata / Leptospermum lanigerum / Lomandra longifolia
Euc. yarraensis / Callistemon sieberii / Dianella tasmanica
Euc. rubida / Bursaria spinosa / Dianella admixta
Euc. radiata
Acacia melanoxylon

DRIER AREAS

TREES / SHRUBS / STRAPPIES
Euc. viminalis / Acacia dealbata / Poa lab.
Euc. rubida / Banksia spinulosa / Lomandra longifolia
Euc. radiata / Indigophera australis / Dianella tasmanica
Acacia melanoxylon / Callistemon sieberii / Dianella admixta
Acacia dealbata
Bursaria spinosa

TYPICAL WET AREA PLANTING COVERING ABOUT 250 SQUARE METRES

ONE 50 METRE BY 2.4 METRE FIBRE ROLL WITH SURROUNDING MONOCOT PLANTINGS:

Euc. viminalis3

Euc. aggrehata3

Euc. ovata3

Euc. yarraensis3

Euc. rubida3

Euc. radiata3

Acacia melanoxylon3

Acacia dealbata20

Leptospermum continentale 20

Leptospermum lanigerum 20

Callistemon sieberii20

Bursaria spinosa20

Total planted in roll of matting121 ( all guarded)

Poa lab.25

Dianella tasmanica25

Dianella admixta25

Carex appressa25

Lomandra longifolia25

Total strappies around matting100 (all unguarded and with one stake each)

Total plants221

Trees and shrubs come in forestry tubes and can be obtained for about $1.10 each including GST from suppliers such as Western Plains Flora. Strappies can often be bought in trays of about 100 cells which work out at about 60 cents per plant. Generally a complete tray of cell plants is purchased, so working out an order on this basis will be cheaper than buying the plants all in tubes. If trying to get local provenance, this supplier will sometimes come and collect local seed but this needs to be done before Xmas for most species. Otherwise WP Flora will supply plants from as close an area as possible - generally the Macedon Ranges area. Orders need to be put in by about May for a Spring planting, otherwise the choice of species would be restricted to what plants were available from stock.

So for the above 221 plants, the typical cost would be about $220 plus delivery if applicable. Below is the typical cost estimate for this sized planting

221 plants$220

Recycled fibre roll $258

500 pins$74

Bale of 500 stakes$75

Box of 500 plastics (not all rqd)$140

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Total plants and hardware$767 plus delivery if required.

Added to this would be the cost of site preparation and some follow up spraying. These costs will vary with every site. The proposed Woodend Primary School planting for Spring 2009 for example will require gorse grooming as well as spraying, so the total budget for this project is around $1,600.

Peter Yates - March 2009