Midori-dake (緑岳), also named Matsuura-dake (松浦岳, after late-Edo Period explorer Matsuura Takeshiro (松浦武四郎)), looms over Daisetsu Kogen Onsen (大雪高原温泉), an area famous for its many small lakes, the beauty of its autumn foliage, and the number of bears that call it home. Along the hiking trail to Midori-dake, you’ll wander through a mixed forest of broad-leaves and conifers, you’ll cross alpine grasslands, and pass the many stony crags that the Daisetsuzan’s de facto mascot, the pika (ナキウサギ), calls home. It’s a splendid hike both at the height of summer and in the depths of autumn.
Daisetsu Kogen Onsen, like nearby Ginsendai (銀線台), puts restrictions on travel by private vehicle for the better part of the month of September, to prevent trail degradation by tourists coming to see the changing leaves. If you’re interested in seeing the leaves, you’ll have to travel to the trailhead by shuttle. Outside of the high period in the autumn, you can visit Daisetsu Kogen Onsen by car. You’ll follow the Yanbetappu River (ヤンベタップ川) along a forest road until you get to Kogen Lodge (高原山荘), where the accommodation and onsen are. Nearby you’ll also find the Ezo Bear Information Center (ヒグマ情報センター), where you can check the advisories for bear sightings before you head into the mountains.
You’ll head up the trail behind the onsen, past the fumaroles and up into a calm forest. In the fall, it will feel like you’re walking through a red-gold tunnel. Climbing hard, you’ll some come to a lookout where you can see the whole alpine wetland. A little further on you’ll arrive at Dai-ichi o-Hanabatake (第一お花畑, ‘No. 1 Flower Meadow’), where it’s likely that some snow will remain in the valleys and ravines. Over the fields of Geum pentapetalum (チングルマ) and Primula cuneiforma (エ ゾコザクラ), you’ll see the massif of Midori-dake itself.
A short ways above Dai-ichi o-Hanabatake, you’ll come to Dai-ni o-Hanabatake (第二お花畑, ‘No. 2 Flower Meadow). Near the trail you may see some places where the soil looks like it’s been dug up —this is the work of bears who eat the the roots of small flowers like Peucedanum multivittatum (ハク サンボウフウ). Near here you’ll also see vast belts of Erman’s birch (Betula ermanii, ダケカンバ) and dwarf stone pine (Pinus pumila, ハイマツ), and beyond, the enormous mountains of the Eastern Daisetsuzan. As you approach the edge of Dai-ni o-Hanabatake you’ll travel along a rockfall so use sufficient caution here.
From here you’ll make a long traverse through a forest of dwarf stone pine. In the fall, when the pinecones are ripe for eating, be on the lookout for hungry chipmunks. Once you’re past the pine forest, you’ll start the long climb up the rocky slope to the summit. You’ll make your way over huge boulders and up steep switchbacks. List for the high-pitched cry of the pika as you go. There is a good amount of Arctous alpina (ウラシマツツジ) along here as well; in the fall you’ll feel like you’re walking across a carpet of deep red.
Though it’s a long climb, you can stop every now and again to catch the huge view behind you: the wetlands below and the great mass of Chubetsu-dake (忠別岳) in the distance. Along the sheer slopes at the edge of the great Takane-ga-hara (高根ゲ原) plateau, some snow may remain; the contrast of the snow against the green of the early summer or the red of autumn is absolutely striking. From the cairn at the summit of Midori-dake you can see the huge plateau stretching out north of Hakuun-dake (白雲岳).
The return trip follows the route that you took up, but if you have extra time on your schedule, the route past Koizumi-dake (小泉岳) to Hakuun-dake is also beautiful. From Koizumi-dake you can also travel on to Aka-dake (赤岳) and descend to Ginsendai—although remember to sort out travel plans beforehand.
For the first half of the summer plenty of snow will remain in the two o-Hanabatake. The flowers are generally at their best from late July to late August. If you climb up out of the wetland basin the Arctous alpina on the ridgeline should be already starting to go red at this time. The red leaves are at their peak in the basin in mid-September, but at this point the trail will so crowded it might just be best to avoid it entirely.
There’s a walking trail near the Ezo Bear Information Center which connects the many small lakes east of Takane-ga-hara (高根ゲ原). As this part of the Daisetsuzan is home to a fair number of bears, keep in mind that this trail might be closed.
Walking in the forest while listening for bears might seem a bit of a tense experience, but the glossy red leaves and the variety of trees make for a diverting walk. Here more than almost anywhere else in the Daisetsuzan you’ll develop an intimacy with the wildlife around you. The full walk around the wetlands takes about 3 hours.