What to Plant Under Crepe Myrtle: Top Companion Plants for Australian Gardens

Why Underplant Crepe Myrtles?

Crepe myrtles (Lagerstroemia spp.) are a favourite in Australian gardens for their stunning summer blooms, attractive bark and deciduous habit that allows winter sun to warm patios or pools. But their lower branches are often pruned to reveal the multi-stemmed trunks, leaving bare soil underneath. Underplanting fills this space, suppresses weeds, improves soil health and creates a layered look.

However, choosing the right companions is key. Crepe myrtles prefer full sun (at least 6 hours daily), well-drained soil and moderate water once established. Their surface roots can compete, so select shallow-rooted, drought-tolerant plants that handle dappled shade from the canopy. In Australia’s diverse climates—from subtropical Queensland to temperate Victoria—opt for frost-hardy options in cooler zones (USDA 8-10 equivalents).

Key Considerations for Australian Gardeners

Climate and Hardiness

Crepe myrtles thrive in warm regions but tolerate light frosts down to -5°C in southern states. Underplantings should match:

• Subtropical/tropical (QLD, NT): Heat-loving, humidity-tolerant plants.
• Mediterranean (WA, SA): Dry summers, wet winters—drought-proof selections.
• Temperate (VIC, TAS, NSW highlands): Frost-resistant, deciduous-friendly plants that cope with bare branches in winter.

Soil and Site Prep

Test soil pH (ideal 5.5-7.0). Amend with compost for drainage but avoid high nitrogen fertilisers that promote leggy growth in companions. Mulch 5-7 cm deep with pine bark or sugar cane to retain moisture and deter weeds.

Light and Water

Canopy provides light shade in summer, full sun in winter. Choose plants needing 4-6 hours sun. Water new plantings weekly for the first season; established setups need little once crepe myrtle roots dominate.

Design Tips

Aim for contrast: fine foliage under bold crepe myrtle leaves, or colour echoes (pink flowers under pink blooms). Space plants 30-60 cm apart for a carpet effect.

Best Groundcovers for Under Crepe Myrtles

Groundcovers knit the soil together quickly, ideal for weed suppression.

• Dichondra repens (Kidney Weed): Native Aussie superstar. Lime-green kidney leaves form a 5-10 cm mat. Thrives in shade to part sun, drought-tolerant once established. Frost-hardy to -5°C. Perfect for all states. Plant 30 cm apart; trim if leggy.
• Mondo grass (Ophiopogon japonicus): Tough, grass-like clumps to 20 cm. Handles dry shade, root competition. Black mondo (O. planiscapus ‘Nigrescens’) adds drama. Suits Sydney to Perth.
• Brachyscome multifida (Rock Daisy): Native with feathery grey foliage and mauve daisy flowers. 15 cm high, loves sun/shade mix. Drought and frost-tolerant. Great for arid zones.
• Liriope muscari: Purple flower spikes in summer, strappy leaves to 40 cm. Very tough, divides easily. Avoid in wet feet areas.

Perennials and Bulbs That Shine Underneath

These add seasonal interest without overwhelming.

• Daylilies (Hemerocallis hybrids): Strappy leaves, lily-like blooms in summer. ‘Stella de Oro’ reblooms reliably. 40-60 cm tall, dormant in winter like crepe myrtle. Handles poor soil, full sun to part shade.
• Salvias (e.g., S. greggii, S. microphylla): Velvety spikes of red/pink flowers echo crepe myrtle hues. 50-80 cm, aromatic foliage deters pests. Prune post-bloom; drought-tolerant.
• Agastache ‘Blue Fortune’: Anise-scented lavender-blue spikes attract bees. 80 cm tall, but shear to keep low. Loves heat, hates wet winters—ideal for east coast.
• Daffodils (Narcissus spp.): Plant bulbs in autumn under bare branches for spring cheer. ‘Tête-à-Tête’ is compact (20 cm). Naturalise easily; lift every 3-4 years.
• Kangaroo paw (Anigozanthos hybrids, dwarf cvs like ‘Bush Gems’): Native with fuzzy flowers. 40-60 cm, sun-loving but copes with dappled light. Best in sandy soils (WA/SA).

Low Shrubs for Structure

For a fuller understorey without crowding trunks.

• Westringia fruticosa (‘Grey Box’ or ‘Naringa’): Native coastal rosemary. Grey foliage, white flowers year-round. 50 cm pruned height, ultra-tough—salt, drought, frost-resistant.
• Grevillea ‘Superbina’ series: Compact natives (40 cm) with red toothbrush flowers. Hummingbird magnet, bird-friendly. Suits most climates.
• Callistemon ‘Little John’ (Dwarf Bottlebrush): 60 cm bottlebrush blooms. Handles dry shade, attracts lorikeets. Prune lightly.

Australian Native Focus

Prioritise natives for low water use and biodiversity:

• Goodenia ovata: Prostrate yellow flowers, 30 cm. Shade-tolerant, erosion control.
• Viola hederacea (Native Violet): Delicate purple/white blooms, creeping habit. Loves moist shade but adapts to dry.
• Scaevola aemula (Fairy Fan Flower): Trailing blue fans, 20 cm. Full sun to part shade, coastal tough.

Planting and Maintenance Guide

1. Prep: Prune crepe myrtle in late winter to open the base. Weed thoroughly, fork in gypsum if clay-heavy.
2. Planting: Autumn or spring best. Dig holes twice pot width, mix 20% compost. Water deeply.
3. Mulch: 5 cm layer, keep off stems.
4. Fertiliser: Slow-release native mix in spring. Avoid high phosphorus near natives.
5. Pruning: Trim perennials post-flowering; groundcovers shear annually if needed.
6. Pests: Watch for aphids on new growth—hose off or use eco-oil.

In summer, companions reduce evaporation; in winter, they protect roots from frost.

Common Mistakes to Avoid

• Overwatering: Leads to root rot in both.
• Deep-rooted plants: Roses or veggies compete and heave.
• Too much shade-lovers: Ferns sulk in summer sun gaps.
• Ignoring scale: Tall plants hide the bark show.

Success Stories from Aussie Gardens

In Brisbane, Dichondra under pink L. indica ‘Musbahia’ creates a lush lawn alternative. Perth gardeners pair Brachyscome with white L. ‘Natchez’. Melbourne uses salvias under L. fauriei for frost-proof colour.

Underplanting transforms crepe myrtles from specimen trees into garden focal points. Experiment with your microclimate—start small and expand. Your garden will bloom with synergy!

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