North Yilliminning reserve is 22 kilometres from Narrogin on the Narrogin-Kulin Road. The road roughly follows the ancient Binneringie dyke, which has been the catchment divide between the Hotham and Blackwood rivers for hundreds of millions of years.
Coming from Narrogin prepare to turn off into a rest bay under Red Morrell trees on the right, soon after passing Taylor Road. Armstrong road marks the eastern side of the reserve.
Coming from Narrogin prepare to turn off into a rest bay under Red Morrell trees on the right, soon after passing Taylor Road. Armstrong road marks the eastern side of the reserve.
The Binneringie dyke is the catchment divide between the Hotham and Blackwood river catchments
The reserve is underlain by granite bedrock, which is mostly hidden under pale sandy, gravelly, and ironstone soils. There is only one small rock outcrop in a valley near the south west edge.
A breakaway following the highway on the northern edge of the reserve is a contact zone between dolerite to the north (fertile York Gum farm land), and granite (sandy soils) to the south.
Between this breakaway and a horseshoe - shaped breakway/ridge to the south is a gently sloping upland, which has remained for millions of years as part of a major catchment divide. The old and infertile soils consist of shallow ironstone and sandy gravel with pale sandy hollows. An old vegetation map of the reserve had colourful descriptions, such as 'poor wandoo' and 'useless plants and dryandra'. The 2021 image shows the tree coverage at this time, with darker tone indicating Red Morrell and Rock Sheoak dominant areas.
A breakaway following the highway on the northern edge of the reserve is a contact zone between dolerite to the north (fertile York Gum farm land), and granite (sandy soils) to the south.
Between this breakaway and a horseshoe - shaped breakway/ridge to the south is a gently sloping upland, which has remained for millions of years as part of a major catchment divide. The old and infertile soils consist of shallow ironstone and sandy gravel with pale sandy hollows. An old vegetation map of the reserve had colourful descriptions, such as 'poor wandoo' and 'useless plants and dryandra'. The 2021 image shows the tree coverage at this time, with darker tone indicating Red Morrell and Rock Sheoak dominant areas.
Radiometric imagery colours in image 3 show general soil types. Orange-brown indicates brownish fertile York gum, jam and rock sheoak soils. Green indicates gravels. Darker colours indicate paler and deeper sand.
Since the devastating bushfire, rampant regrowth has created a riot of flowering shrubs and herbs which are well worth a visit, although orchid flowering will be suppressed for some years.
Since the devastating bushfire, rampant regrowth has created a riot of flowering shrubs and herbs which are well worth a visit, although orchid flowering will be suppressed for some years.
 1. 2021 image before fire |  2. 2023 image light =sands |  3. Radiometrics image |
This is attractive bushwalking country, but regrowth and ironstone rocks make walking difficult and confusing for visitors. Before a 2022 fire there was a multitude of Cowslip Orchids. Litttle Pink Fairy Orchids with with Sugar, Snail greenhood, Jug, and Donkey Orchids, and a patch of Purple Enamel Orchids. Unlike many surrounding reserves there are very few spider orchids.
Surprisingly numerous Cowslip/Little Pink Fairy orchid hybrids, flourish on these soils, and are described in this blog. They have been suppressed by regrowth, but to see some park near the picnic table and walk up to the ridge. A narrow dead end track (which can scratch cars) on the left leads south downhill. Check the mature sheoak grove on the right (western) side. Do not pick wildflowers.
Surprisingly numerous Cowslip/Little Pink Fairy orchid hybrids, flourish on these soils, and are described in this blog. They have been suppressed by regrowth, but to see some park near the picnic table and walk up to the ridge. A narrow dead end track (which can scratch cars) on the left leads south downhill. Check the mature sheoak grove on the right (western) side. Do not pick wildflowers.
A bushfire devastated the reserve in 2022.
Images below show landscapes in the reserve before and after the fire.
Images below show landscapes in the reserve before and after the fire.
A Banksia attenuata deep sand area is on on the north eastern side of the reserve (opposite the hay shed). No Banksia regeneration. The banksias have not regrown or germinated. Initially weeds herbs and Cowslip Orchids appeared but they are being engulfed by Rock Sheoak seedling thicket.
 2021 mature Banksia woodland  2024 Still no banksias |  2022 all growth dead  2025 Dense rock sheoak |  2023 Only weeds herbs and orchids |
Downhill of the Banksias, the land merges into Jarrah pale sand over ironstone. Most of the jarrah resprouted. Initially there was rapid herb and native grass regeneration followed by shrubs and rock sheoak thicket in some spots
 2021 low shrubs on sand |  2022 total burn | 2023 shrubs and native grass growth |
 2024 larger shrubs |  2025 more understorey growth. Sheoaks in background |  2025 view to banksias |
Red Morrell loam below breakaway. The fire was not so severe here because the morrell forest had almost no understorey. Fire burnt the base of the trees and caused a leaf drop. Trees resprouting and growing new leaves and vigourous understorey germination.
 Typical Red Morrell grove |  2022 Leaf drop and trunks scorched |  2022 Resprouting |
 2024 trees resprouting more germination |  2025 Acacia flowers |
Wandoo plateau stony gravel woodland bounded by a breakaway to the west was completely incinerated. many burnt wandoos are resprouting and there has been a dense germination of Acacia pulchella / Prickly Moses seedlings, which is becoming too thick and prickly to penetrate.
 2022 complete devastation |  2023 some wandoo resprouting |  2024 dense Prickly Moses wattle germination |
Rock Sheoak stony gravel plateau slope. In 2021this area had numerous Cowslip/ Little Pink Fairy Orchid hybrids scattered through degraded rock sheoak woodland. After the fire there was profuse shrub regrowth, and rock sheoak seedlings will suppress orchid growth for a number of years.
 2021 dense living and dead sheoak woodland  2024 dense shrub growth, sheoak seedlings |  2022 Area incinerated  2025 thick sheoak and acacia understorey |  2023 flowering herbs and shrubs and grass regrowth |
Thin wandoo sheoak gravel, sand over gravel on the upland plain. Wandoos reprouted, massive regeneration of the understorey from pre-fire situation
 2021 sparse understorey |  2022 Completely burnt |  2024 dense understorey |
2025 dense prickly understorey
Grass tree group on stony gravel. Most grass trees survived and shrub understorey has been rejuvenated.
This blog shows year by year changes at photomonitoring sites I set up after the fire.
 2021 sparse understorey  2025 Dense sheoak regrowth |  2023 most grass trees survived |  2024 strong understorey growth |
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