Dark bitter bolete, Caloboletus conifericola, is a mycorrhizal mushroom that forms symbiotic relationships with conifer trees, especially pines, in western North America. It typically appears as a sturdy, stout bolete with a dark brown cap, yellow pores that bruise blue, and a thick, pale to yellowish stem. This species grows on the ground in forest soil, often in small groups, during the warmer, wetter seasons. Its very bitter flesh makes it undesirable as an edible species and helps prevent accidental consumption. Because it relies on living conifers, it is not practical to cultivate indoors or in typical gardens, so attempts to care for Dark Bitter Bolete focus mainly on conserving its natural forest habitat.
Care Difficulty
Hard Care
Light Preference
Partial Shade
Water Requirements
Keep Soil Moist
Temperature Preference
Cool Climate
Hardiness Zone
5–9
Soil Texture
Loamy, Sandy, Organic-rich
Soil pH
Acidic (5.5–6.5)
Soil Drainage
Moist but well-drained
Fertilization
Minimal (feed rarely)
Scan your plant to receive care tips personalized for your specific plant
Available on iOS and Android
This mycorrhizal mushroom prefers dappled forest light rather than direct, open sun.
This ectomycorrhizal fungus depends on consistently moist, not soggy, forest soil.
This species fruits in cool to mild conditions typical of conifer forests.
This mycorrhizal mushroom is not suited to controlled indoor humidity and is best left in its natural outdoor forest conditions.
This fungus relies on natural forest soil rather than prepared mixes, because it forms a mycorrhizal partnership with conifer roots.
This species is not suitable for container growing because it requires a long-term symbiosis with living conifer roots in undisturbed ground.
Caloboletus conifericola is a wild mycorrhizal fungus that usually does not need added fertilizer when growing in suitable coniferous woodland soil.
Pruning is not applicable to Caloboletus conifericola, as it is a wild, seasonal mushroom rather than a managed garden plant.
This species is not suited to typical repotting; it forms a mycorrhizal partnership with conifer roots and is best left in stable soil conditions.
Propagation of Caloboletus conifericola is indirect and relies on spore dispersal and successful association with suitable conifer hosts.
This wild fungus is naturally cold hardy in its native range and does not require specific winter care from gardeners when growing Dark Bitter Bolete in situ.
Plant Health Check
Not sure what's wrong with your plant? Check your plant's health inside the app.
This dark-capped bolete is considered inedible because of its strongly bitter taste, yet it is not regarded as poisonous and does not have the toxic profile of some other boletes such as the rubroboletus group.
The species forms ectomycorrhizal partnerships with conifer trees, especially pines and related species in western North America, exchanging mineral nutrients from the soil for sugars produced by its host.
When the yellow pores or flesh are handled or damaged, they quickly stain bluish due to oxidation of specific pigment compounds, a reaction commonly used by field mycologists to separate it from similar boletes.
This bolete was only relatively recently segregated into the genus Caloboletus after molecular phylogenetic studies showed that several traditionally named Boletus species in conifer forests of western North America formed a distinct evolutionary lineage.
This mushroom is considered inedible due to its very strong bitter taste, which ruins dishes even in small amounts. It is not recommended for culinary use, although it is not usually classified as dangerously poisonous.
Keep your plants happy and healthy with plant identification, disease detection, and easy care guidance.
