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Plant care

Mountain Rimu (Bog Pine) care

Dacrydium bidwillii

Also called Bog Pine, Mountain Pine, New Zealand Mountain Rimu.

RHS H4USDA 8-10Mildly toxic to petsIndoor 0.3-1.5 m tall

Watering rhythm

7-14days

Every 7-14 days; keep soil consistently moist, especially in summer

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Light

Bright indirect light (just back from a sunny window)

Soil

Moist, peaty, acidic, well-aerated soil

Humidity

Ambient to high (50-80%)

Temp

-5 to 20°C

Pet safety

Mildly toxic to pets

Mature size

0.3-1.5 m tall

Care at a glance

Light

Bright but filtered. Mountain Rimu burns within days in unfiltered south-facing summer sun, and stops growing within months in deep shade. Thrives in full sun to partial shade in cool climates. In warmer zones, light afternoon shade prevents foliage scorch. It naturally grows in open, exposed subalpine conditions but benefits from shelter from hot drying winds. If you only have a south window, set the plant back 1.5 m or hang a sheer curtain — both knock the intensity down into the right range.

Watering

Watering mountain rimu: every 7-14 days; keep soil consistently moist, especially in summer. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Naturally occurs in boggy and wet montane soils; appreciates consistent moisture without becoming waterlogged. Mulch heavily to retain soil moisture and keep roots cool.

Soil and pot

Mountain Rimu grows best in moist, peaty, acidic, well-aerated soil. Prefers acidic conditions (pH 4.5–6.0) rich in organic matter. A mix of peat substitute, bark, and grit replicates its native habitat. Avoid alkaline or compacted soils. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Mountain Rimu sits happiest at around Ambient to high (50-80%) humidity and -5 to 20°C (23 to 68°F). Naturally adapted to moist montane environments. In garden settings, regular watering and mulching keep conditions suitably humid around the roots. Misting foliage is not required. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed mountain rimu sparingly. Apply a slow-release ericaceous fertiliser in early spring. Ericaceous (acid-forming) feeds help maintain soil acidity. Avoid over-fertilising as this podocarp is adapted to low-nutrient conditions. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on mountain rimu in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Foliage browning — Caused by dry soil or desiccating winds. Keep soil moist and provide wind shelter.
  • Poor growth in alkaline soil — Chlorosis and slow growth indicate high pH. Amend soil with sulphur or use ericaceous compost.
  • Root rot in heavy clay — Improve drainage by incorporating grit into planting hole and mound planting if needed.
  • Scale insects — Occasionally infest foliage. Treat with horticultural oil applied when crawlers are visible in spring.

Companion plants

Mountain Rimu pairs well with Gaultheria mucronata, Empetrum nigrum, Hebe pinguifolia, and Aciphylla squarrosa. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Take semi-ripe cuttings in late summer and root under gentle bottom heat in an acidic cutting medium. Seeds can be sown in acidic compost in spring but germination is slow; cuttings are more reliable for retaining the parent plant's characteristics. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Mountain Rimu is mildly toxic to pets. Dacrydium bidwillii is not individually listed by the ASPCA. Some podocarp species produce fleshy, berry-like arils that can cause gastrointestinal upset if consumed in quantity by pets or children; treat as mildly toxic until specific safety data is confirmed. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Mountain Rimu care — frequently asked questions

What is the common name for Dacrydium bidwillii?

Dacrydium bidwillii is most commonly called Mountain Rimu, but it is also known as Bog Pine, Mountain Pine, New Zealand Mountain Rimu. The names refer to the same species, so care instructions for Mountain Rimu apply identically to anything sold as Bog Pine.

How much light does mountain rimu need?

Mountain Rimu grows best in bright indirect light (just back from a sunny window). Thrives in full sun to partial shade in cool climates. In warmer zones, light afternoon shade prevents foliage scorch. It naturally grows in open, exposed subalpine conditions but benefits from shelter from hot drying winds.

How often should I water mountain rimu?

Water mountain rimu every 7-14 days; keep soil consistently moist, especially in summer. Naturally occurs in boggy and wet montane soils; appreciates consistent moisture without becoming waterlogged. Mulch heavily to retain soil moisture and keep roots cool. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is mountain rimu toxic to cats and dogs?

Mountain Rimu is mildly toxic to pets. Dacrydium bidwillii is not individually listed by the ASPCA. Some podocarp species produce fleshy, berry-like arils that can cause gastrointestinal upset if consumed in quantity by pets or children; treat as mildly toxic until specific safety data is confirmed.

What USDA hardiness zone does mountain rimu grow in?

Mountain Rimu is rated for USDA zone 8-10 and RHS hardiness H4. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Mountain Rimu deep-dive guides

Every aspect of mountain rimu care, each with its own calibrated guide:

Featured in these plant shortlists

Mountain Rimu qualifies for 4 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Mountain Rimu is also known as Bog Pine, Mountain Pine, and New Zealand Mountain Rimu.