Blue star creeper

Sun

Full sun to partial shade; provide afternoon shade in hot climates.

Water

Keep the root zone evenly moist, especially while establishing and during hot weather. Avoid prolonged waterlogging.

Soil

Moist, humus-rich soil with good drainage; tolerates a range of soil textures if neither parched nor stagnant.

Height

0.1-0.2 ft (0.03-0.06 m)

Spread

1-2 ft (0.3-0.6 m), eventually wider where stems can root

Flowers

Pale blue to blue-lilac flowers from late spring through summer, sometimes continuing into autumn in mild climates.

Foliage

Tiny green leaves on slender, creeping stems that root as they spread. Evergreen in mild climates, but may become dormant or lose foliage after frost.

Growth

Moderate to fast in moist, mild conditions

Care needed

Medium

• Pollinators
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   0 ft (0.01 m)

2. After 1 year

   0.1 ft (0.03 m)

3. After 2 years

   0.1 ft (0.05 m)

   full size

About 2 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Mildly toxic: may upset a stomach

Native to

Australia

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Fast

• Water new plants regularly until their stems have rooted into the surrounding soil.
• Water during dry spells before the shallow-rooted mat dries out completely.
• Apply a light dressing of compost in spring; avoid heavy feeding.
• Keep thick mulch off the creeping stems and small leaves.
• Lift rooted stems that stray into lawns or neighbouring plants before they become established.

Pruning. Trim spreading edges during the growing season and remove the rooted pieces rather than leaving them on moist soil. In spring, lightly clip away winter-damaged growth once new shoots appear.

Spring

Remove winter-damaged foliage and check that drainage is adequate.

Spring

Plant or divide rooted sections, water thoroughly and keep moist while establishing.

Late spring

Weed carefully before the mat thickens and flowers open.

Summer

Water during dry weather and trim stems spreading beyond their allotted space.

Autumn

Remove fallen leaves that would smother the low foliage.

Winter

Avoid walking on frozen or saturated mats and keep drainage outlets clear.

• Plant in soil-filled joints between widely spaced stepping stones on lightly used paths.
• Use as a low edging beside a moist border, with a firm boundary to limit spread.
• Grow beneath small shrubs in bright, dappled shade for a fine-textured green carpet.
• Let it trail over a container rim beside plants with similar moisture needs.

Garden styles it suits: Cottage garden, Woodland, Modern courtyard, Small-space, Australian native and Blues and silvers.

Plant it with: Japanese painted fern, Hosta, Coral bells, Japanese sedge, Astilbe and Primrose.

Wildlife: The small flowers attract visiting insects. It is not a substitute for a varied planting of locally native flowering plants.

• Brown, thinning patches during drought: water deeply enough to moisten the shallow root zone and provide afternoon shade in hot sites.
• Rot and dieback in saturated soil: improve drainage and avoid sites that remain waterlogged through winter.
• Slugs and snails damaging young growth: remove hiding places, hand-pick at dusk or use a locally approved iron-phosphate bait as directed.
• Stems overrunning nearby plants or paving: lift unwanted rooted sections regularly; clipping the tops alone will not remove them.

Reliable species-specific information for cats, dogs, horses and people is limited, so it should not be described as known to be non-toxic. Treat all parts and sap as potentially harmful if eaten, prevent grazing or chewing, and seek veterinary or medical advice after ingestion; the seriousness of poisoning is not well established for this species.

Where it spreads. Can spread aggressively through moist garden beds and paving joints in mild regions, including the Pacific Northwest of the United States. Garden spread does not by itself mean it is officially listed as invasive; check local guidance before planting near natural areas.

• Blue star creeper (Lobelia fluviatilis)

  A closely related plant sold under the same common name, often as Isotoma fluviatilis. Nursery names are frequently confused;

• Baby's tears (Soleirolia soleirolii)

  Forms a soft mound of tiny rounded leaves but has inconspicuous flowers, not visible blue stars.

• Irish moss (Sagina subulata)

  Has narrow, needle-like leaves and small white flowers rather than broader leaves and blue flowers.

Blue star creeper describes its star-shaped blue flowers and creeping habit, while pedunculata refers to its stalked flowers.

Propagation. Divide rooted sections in spring or early autumn and replant promptly. Small stem sections with roots attached establish readily if kept moist.

Accepted botanical name

Lobelia pedunculata

Native range

New South Wales, Queensland, South Australia, Tasmania and Victoria.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.