Dendrobium speciosum
rock orchid
Overview
Dendrobium speciosum is an evergreen orchid that grows on rocks (lithophytic) or trees (epiphytic), forming dense clumps 12-40 inches (30-100 cm) across. Stout club-shaped pseudobulbs 4-12 inches (10-30 cm) long taper from a swollen base, each topped by two to five thick, leathery dark green leaves 4-10 inches (10-25 cm) long. From the top of mature pseudobulbs arise arching to pendulous flower spikes 8-24 inches (20-60 cm) long, each carrying dozens of fragrant, star-shaped flowers. Individual flowers are 0.6-1.2 inches (15-30 mm) across, cream to golden yellow, with narrow pointed sepals and petals and a white labellum streaked with purple. Flowering occurs in late winter and spring. Plants are slow-growing, often taking 4-6 years from division to first flowering, and clumps may not bloom every year where light or seasonal cooling is insufficient.
Native Range
Native to eastern Australia, from eastern Victoria through New South Wales to central Queensland. Grows on exposed rock faces, boulders, and tree trunks in open forest and rainforest margins, from coastal areas to elevations near 4,000 feet (1,200 m).Suggested Uses
Grown mounted on rocks, logs, or cork slabs, in hanging baskets, or in rockeries and courtyards in frost-free climates. Used as a long-lived feature in container and bush-house collections. The slow growth and need for a cool winter limit reliable flowering in warm tropical gardens.How to Identify
Appearance
Size & Dimensions
Height1' - 2'
Width/Spread1' - 3'4"
Reaches mature size in approximately 6 years
Bloom Information
Flowers from August to October, across late winter and spring. A single flowering spike lasts 2-4 weeks, and a large clump may carry sprays in sequence over 4-6 weeks. Flowering is triggered by cool autumn and winter temperatures; plants in frost-free, mild climates may flower sparsely or skip years.
Detailed Descriptions
Flower Description
cream to golden yellowFoliage Description
dark greenGrowing Conditions
Sun Requirements
Requires 4-6 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grows in coarse, free-draining orchid mix, mounted on cork or rock, or sited in an open position with bright, indirect light. Water freely during the warm growing season and reduce water through winter to mimic the natural dry rest. Good air movement keeps the pseudobulbs and roots free of rot. A cool winter with night temperatures of 45-55 degrees F (7-13 C) promotes flower-spike formation. Scale insects and snails feed on new growth and buds. Established clumps are slow to recover after division.Pruning
Remove spent flower spikes at the base once flowering finishes. Cut away shrivelled or dead pseudobulbs and damaged leaves to limit rot and pests. Living pseudobulbs store water and nutrients and are retained even when leafless. No other pruning is needed.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
late spring
Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons