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Zieria spp.
Overview
Zieria is a genus of about 60 aromatic evergreen shrubs in the citrus family, almost all native to Australia, with a single species in New Caledonia. Most are small to medium shrubs, ranging from under 1 ft (0.3 m) to about 10 ft (3 m) tall, with opposite leaves divided into three leaflets that release a strong scent when crushed; the aroma varies by species from citrus-like to pungent. Clusters of small star-shaped flowers, each with four petals, open from late winter into spring in shades of white to pink. Zieria closely resembles the related Boronia but has four stamens rather than eight, a reliable point of separation. Foliage and stems are often dotted with oil glands typical of the family. Many species have very restricted ranges and a number are listed as rare or threatened in the wild. Most are frost-tender and require sharp drainage, and some are short-lived in cultivation, which keeps the genus mainly in the hands of native-plant growers rather than in general garden use.
Native Range
Zieria is native chiefly to Australia, where it occurs in every mainland state and is most diverse in eastern New South Wales and Queensland; one species reaches New Caledonia. The shrubs grow in heath, dry sclerophyll forest, and rocky outcrops, often on shallow, nutrient-poor soils.Suggested Uses
Zieria is grown in Australian native gardens, low-water and coastal plantings, and rockeries in frost-free regions. The aromatic foliage and spring flowers suit informal shrub borders and containers. Frost sensitivity, drainage needs, and the short life of some species limit it to specialist and regional plantings.How to Identify
Appearance
Size & Dimensions
Height1' - 10'
Width/Spread1' - 6'
Bloom Information
Flowering runs mainly from late winter into spring, broadly August to November in the southern hemisphere. Branched clusters of small four-petalled flowers cover the shrubs and draw native bees and other insects. Dry, segmented capsules follow and split to eject the seeds.
Detailed Descriptions
Flower Description
White to pinkFoliage Description
Green, aromaticGrowing Conditions
Sun Requirements
Requires 5-9 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
Zieria needs full sun to light shade and sharply drained sandy, loamy, or rocky soil with a pH around 5.5 to 7.0. As a member of the citrus family from lean habitats, it grows on low-phosphorus soils and is sensitive to standard fertilizers. Established plants tolerate dry spells, but most are frost-tender and suit only mild, warm-temperate to subtropical climates. Good air movement and free drainage reduce the root-rot and fungal problems to which the genus is prone. Light, regular tip pruning keeps plants bushy, since some species grow open and woody with age.Pruning
Light tip pruning after flowering keeps Zieria compact and slows the tendency to become open and woody. Hard cutting into bare old wood is avoided, since regrowth from leafless stems is unreliable. Spent flower clusters are trimmed along with the tips.Container Growing
Suitable for container growing
Minimum container size: 3 gallons