How to Grow Cushion Plant, New Zealand Mattress Plant
Wikimedia Commons
Cushion Plant, New Zealand Mattress Plant
Raoulia australis
flowerRaoulia australis is a diminutive alpine cushion plant native to New Zealand that forms dense, moss-like mounds of tiny silvery-green leaves. This slow-growing groundcover rarely exceeds 1 inch in height and produces minuscule cream-colored flowers in summer. It is prized by alpine gardeners and rock garden enthusiasts for its unique texture and architectural form.
When should you plant Cushion Plant, New Zealand Mattress Plant in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Cushion Plant, New Zealand Mattress Plant timeline · Pittsburgh, PA (Zone 6b)
-
Plant Cushion Plant, New Zealand Mattress Plant
Around Apr 17Near Pittsburgh's average last spring frost.
-
Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
-
First Cushion Plant, New Zealand Mattress Plant blooms
Mid-to-late summerBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Cushion Plant, New Zealand Mattress Plant dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 6-8; can survive zone 5b with winter protection
Sign up free to see if Cushion Plant, New Zealand Mattress Plant grows in your zone — and get a personalized planting timeline.
Get my Cushion Plant, New Zealand Mattress Plant timeline →Growth Stages
Establishment
3-6 monthsYoung plant is tiny rosettes of silvery leaves forming a small mound. Growth is imperceptibly slow during first season.
Keep soil consistently but lightly moist (not wet). Provide excellent drainage. Protect from heavy rain and frost heave. Avoid fertilizer.
Flowering
4-6 weeksMinuscule cream or pale yellow flowers appear on the surface of the cushion in mid to late summer. Flowers are barely noticeable without close inspection.
Continue regular but light watering during bloom. Do not fertilize. Flowers are self-fertile but pollination is often wind-assisted.
Seed Production & Dormancy
3-4 monthsFlowers fade and tiny seeds form. Plant enters slow winter dormancy. Mound may appear slightly drab or greyed during cold months.
Reduce water sharply in fall and winter. Ensure excellent drainage to prevent rot. Avoid watering during wet weather. A protective grit top-dressing helps shed excess moisture.
Mature Cushion
Ongoing; slow growth indefinitelyEstablished plants form a perfect, tight hemisphere of silvery foliage. Growth becomes even slower; annual expansion is minimal.
Minimal maintenance once established. Light watering only during extended drought. Do not fertilize. Can remain in same location for 10+ years.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
-
Prevent through meticulous drainage and avoiding overwatering. If affected, allow soil to dry completely. Remove affected portions and repot in fresh, sterile gritty mix. Fungicides rarely effective once established.
-
and
Lay copper tape around pots or use beer traps. Hand-pick during damp evenings. Avoid slug pellets which can poison the soil. Keep area relatively dry to discourage slug activity.
-
Spray with water to dislodge. In severe cases, use horticultural oil or neem oil, though rarely needed. Improve air circulation.
-
Spray directly with water or use insecticidal soap. Remove affected portions if infestation is severe. Rarely a serious problem for established plants.
Uses
Alpine Rock Garden Display
CraftRaoulia australis is a prized specimen for alpine troughs, raised beds, and rock gardens where its perfectly sculpted cushion form creates a living sculpture. Its silver-green color and architectural form provide year-round visual interest. [source]
Container Gardening & Bonsai-Style Cultivation
CraftIdeal for shallow pots, ceramic troughs, and alpine containers where drainage can be perfectly controlled. Extremely slow growth makes it suitable for collectors of miniature and specimen plants. [source]
Pollinator & Insect Habitat
WildlifeThe tiny flowers attract small native bees, flies, and other alpine pollinators. Despite its diminutive size, it provides important nectar and pollen for montane insects. [source]
Living Sculpture & Specimen Collection
HouseholdOften grown by plant collectors and alpine enthusiasts as a prized specimen. Its slow growth rate and unique aesthetic appeal make it a long-term investment piece for serious gardeners. [source]
No Known Culinary Use
CulinaryThis plant is not edible and has no culinary applications. It is grown purely for ornamental purposes. [source]
Harvest Tips
This is an ornamental plant, not harvested for food. Seeds can be collected in late summer by allowing the cushion to dry completely and gently brushing the surface to release tiny seeds. Seed propagation is extremely slow and difficult; vegetative division of mature cushions is more practical for propagation.
Fun Facts
- 🌱 Raoulia australis grows at an incredibly slow rate—often expanding less than 1 inch per year—making a mature cushion several inches across potentially over 10 years old.
- 🌱 The plant's silvery coloration comes from dense, fine hairs on the leaves that help it reflect intense high-altitude UV light and reduce water loss in alpine environments.
- 🌱 New Zealand's high mountain regions where this plant grows experience extreme temperature fluctuations and intense direct sunlight, and Raoulia has evolved this cushion form to minimize wind exposure and conserve moisture in harsh, exposed alpine terrain.
Gardening Terms
New to gardening? Learn about terms used in this guide:
Join 30,000 gardeners planning their gardens with LizPlants.
Get your personalized Cushion Plant, New Zealand Mattress Plant planting timeline
Tell us your zip code and we'll calculate exactly when to start Cushion Plant, New Zealand Mattress Plant seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.
Get my Cushion Plant, New Zealand Mattress Plant timeline →