Longflower Mertensia Plant Care
Mertensia longiflora Greene
Updated · Sources · How we source care data
Mertensia longiflora is a species of flowering plant in the borage family known by the common names small bluebells and long bluebells.
Every 3–5 days
Partial shade to full shade
50–75°F
40–60%
At a glance
How do you care for Longflower Mertensia?
Water Longflower Mertensia every 3–5 days, letting the top layer of soil dry out between waterings, and give it partial shade to full shade. It prefers temperatures of 50–75°F (10–24°C) and 40–60% humidity. Fertilize it every 6 months during the growing season.
What Is the Longflower Mertensia?
Longflower Mertensia (Mertensia longiflora) belongs to the Boraginaceae family within the Mertensia genus. Longflower Mertensia is also known as Bluebells.
Longflower Mertensia displays a clumping herbaceous perennial growth habit, reaching up to 1 ft tall with a spread of approximately 1 ft. Longflower Mertensia produces tubular, bell-shaped flowers in shades of blue and pink.
Leaf size: approximately 3 inches.
How Often Should You Water a Longflower Mertensia?
Mertensia longiflora requires watering every 3–5 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 3–5 days
Let soil partially dry between waterings
What Light Does the Longflower Mertensia Need?
Longflower Mertensia thrives in partial shade to full shade. The optimal light range is 100–500 lux. Avoid placing Longflower Mertensia in direct, harsh sunlight for extended periods, as this can scorch the foliage.
Light Requirement
Partial shade to full shade
100–500 lux
What Temperature and Humidity Does the Longflower Mertensia Prefer?
Mertensia longiflora grows best at temperatures of 50–75°F. Longflower Mertensia prefers humidity levels of 40–60%.
Temperature
50–75°F
Humidity
40–60%
What Soil Mix Works Best for a Longflower Mertensia?
Moist, well-draining soil with high organic content. Good drainage is essential for Longflower Mertensia to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Longflower Mertensia?
Feed Longflower Mertensia every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Longflower Mertensia?
Repot every 2-3 years in early spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Longflower Mertensia?
Longflower Mertensia can be propagated through seeds, division. Similar propagation techniques also apply to arizona bluebells plant care, which shares the same genus.
Is the Longflower Mertensia Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Longflower Mertensia, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Longflower Mertensia?
Longflower Mertensia is susceptible to aphids, spider mites, slugs. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Longflower Mertensia Need?
Longflower Mertensia grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. In cooler regions, grow Longflower Mertensia as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Longflower Mertensia is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Mertensia genus — compare its care with other Mertensia species on PlantoScan.
Mertensia is part of the Boraginaceae plant family — browse all Boraginaceae genera and species.
Longflower Mertensia copes with lower light than most plants — browse the full list of low-light plants.
More Mertensia Species
Other Mertensia species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Mertensia longiflora Greene, family Boraginaceae (first published in Pittonia 3: 261 (1898)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Longflower Mertensia, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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