Photo: no rights reservedCC0 1.0via iNaturalist
Weak bluegrass Plant Care
Poa infirma Kunth
Updated · Sources · How we source care data
With its delicate, wispy leaves and sprawling growth habit, this plant from New Zealand is a favorite among plant collectors looking to add a touch of uniqueness to their collection. Originating from the lush forests of New Zealand, Poa infirma's soft green color and graceful appearance make it a desirable addition to any indoor garden.
Every 3–7 days
Full sun to part shade
50–80°F
40–70%
At a glance
How do you care for Weak bluegrass?
Water Weak bluegrass every 3–7 days, letting the top layer of soil dry out between waterings, and give it full sun to part shade. It prefers temperatures of 50–80°F (10–27°C) and 40–70% humidity. Fertilize it every month during the growing season.
Where Is the Weak bluegrass Native To?
- Albania
- Austria
- Belarus
- Belgium
- Bosnia and Herzegovina
- Bulgaria
- Croatia
- Cyprus
- Czechia
- Denmark
- Estonia
- Finland
- France
- Germany
- Greece
- Hungary
- Iceland
- Ireland
- Italy
- Latvia
- Lithuania
- Luxembourg
- Malta
- Moldova
- Montenegro
- North Macedonia
- Norway
- Poland
- Portugal
- Romania
- Russia
- Serbia
- Slovakia
- Slovenia
- Spain
- Sweden
- Switzerland
- The Netherlands
- Ukraine
- United Kingdom
What Is the Weak bluegrass?
Weak bluegrass (Poa infirma) belongs to the Poaceae family within the Poa genus. Weak bluegrass is native to Europe. Weak bluegrass is also known as Glaucous poa.
Weak bluegrass displays a grass-like perennial growth habit, reaching up to 1 ft tall with a spread of approximately 0.5 ft. Weak bluegrass produces small inconspicuous flowers in clustered spikelets.
Leaf size: approximately 12 inches.
How Often Should You Water a Weak bluegrass?
Poa infirma requires watering every 3–7 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 3–7 days
Let soil partially dry between waterings
What Light Does the Weak bluegrass Need?
Weak bluegrass thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Weak bluegrass Prefer?
Poa infirma grows best at temperatures of 50–80°F. Weak bluegrass prefers humidity levels of 40–70%.
Temperature
50–80°F
Humidity
40–70%
What Soil Mix Works Best for a Weak bluegrass?
Well-draining loamy soil with good fertility. Good drainage is essential for Weak bluegrass to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Weak bluegrass?
Feed Weak bluegrass every month 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 month
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Weak bluegrass?
Divide clumps 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 Weak bluegrass?
Weak bluegrass can be propagated through division, seed. Similar propagation techniques also apply to grove bluegrass plant care, which shares the same genus.
Is the Weak bluegrass Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Weak bluegrass, 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 Weak bluegrass?
Weak bluegrass is susceptible to aphids, cutworms, grasshoppers. 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 Weak bluegrass Need?
Weak bluegrass grows outdoors in USDA Zone 8a – 10b. It survives winters down to planting zone 8a. Weak bluegrass is native to Europe.
Hardiness Zone
Zone 8a – 10b
Keep exploring plants
Weak bluegrass 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 Poa genus — compare its care with other Poa species on PlantoScan.
Poa is part of the Poaceae plant family — browse all Poaceae genera and species.
Weak bluegrass thrives in bright light and direct sun — see other bright-light plants.
More Poa Species
Other Poa species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Poa infirma Kunth, family Poaceae (first published in Nov. Gen. Sp. 1: 158 (1816)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Weak bluegrass, 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.
- Photo: Public domain, CC0 1.0, iNaturalist — original.
- Hardiness zone: USDA Zone 8a – 10b, estimated from the plant's typical growing conditions.
- 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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