Silver Thyme
Eucalyptus gunnii
Silver Thyme is a classic heirloom herb prized for its distinctive silvery-green foliage and aromatic intensity. This easy-to-grow perennial reaches maturity in 120-150 days, producing delicate flowers that attract pollinators. The leaves deliver authentic thyme flavor—earthy, minty, and subtly floral—making it ideal for culinary applications, particularly Mediterranean dishes and herbal infusions. Hardy and drought-tolerant, Silver Thyme thrives in well-drained, sandy, or rocky soil with minimal care, distinguishing it through superior flavor complexity compared to common thyme varieties.
Harvest
120-150d
Days to harvest
Sun
Full sun
Zones
7–10
USDA hardiness
Height
6-12 inches
Planting Timeline
Showing dates for Silver Thyme in USDA Zone 7
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Silver Thyme · Zones 7–10
Growing Details
Zone-by-Zone Planting Calendar
Complete Growing Guide
Light: Full sun (6 or more hours of direct sunlight a day). Drainage: Good Drainage. Growth rate: Rapid.
Harvesting
many-seeded capsule
Type: Capsule.
Storage & Preservation
Fresh silver thyme keeps best when stems are placed in water like cut flowers, then loosely covered with a plastic bag and refrigerated. This method maintains quality for 7-10 days. Alternatively, wrap unwashed stems in slightly damp paper towels and store in the refrigerator's crisper drawer for up to one week.
For long-term storage, air-drying preserves both flavor and the attractive variegated appearance. Bundle 4-6 stems together and hang in a warm, dry, well-ventilated area away from direct sunlight. Properly dried silver thyme retains excellent flavor for up to one year when stored in airtight containers.
Freezing works well for culinary use—strip leaves from stems and freeze in ice cube trays with olive oil or water. The variegated leaves lose their visual appeal when frozen but maintain their classic thyme flavor perfectly for cooking applications.
History & Origin
Origin: Philippines to Australia
Advantages
- +Attracts: Bees
- +Fast-growing
Considerations
- -Toxic (Bark, Leaves): High severity
- -Causes contact dermatitis
Companion Plants
Silver Thyme does well next to other low-water Mediterranean herbs — rosemary, lavender, and oregano share the same preference for lean, well-drained soil and full sun, so they won't compete for resources or create the persistent moisture around the root zone that invites Pythium. Grouping them also concentrates aromatic compounds in one area, which tends to confuse aphids and spider mites (Tetranychus urticae) searching for host plants. Cabbage and other brassicas get a real benefit from thyme nearby because the volatile oils help mask the scent cues that guide cabbage worm moths (Pieris rapae) to lay eggs.
Mint is a bad neighbor for a simple physical reason: it spreads via underground runners and will crowd thyme out within a single growing season, and it wants consistently moist soil — exactly the conditions that put Silver Thyme at risk for root rot. Black walnut (Juglans nigra) is a different problem entirely. It exudes juglone from its root system, a compound that disrupts respiration in many herbaceous plants; keep thyme at least 50 feet from the canopy drip line of any established walnut.
Plant Together
Rosemary
Similar growing conditions, both repel cabbage moths and carrot flies
Lavender
Compatible Mediterranean herbs that deter pests and attract pollinators
Cabbage
Thyme repels cabbage worms and flea beetles that damage brassicas
Tomatoes
Thyme deters hornworms and aphids while improving tomato flavor
Strawberries
Thyme repels ants and improves strawberry flavor and growth
Carrots
Thyme repels carrot rust flies and other root vegetable pests
Eggplant
Thyme deters flea beetles that commonly attack eggplant leaves
Oregano
Compatible Mediterranean herbs with similar care needs and pest-repelling properties
Keep Apart
Black Walnut
Releases juglone toxin that inhibits growth of most herbs including thyme
Mint
Aggressive spreader that competes for space and nutrients, different water needs
Cilantro
Requires more water and different growing conditions than drought-tolerant thyme
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #173470)
Pests & Disease Resistance
Resistance
Excellent disease resistance, very hardy and pest resistant
Common Pests
Spider mites in hot, dry conditions, root rot if overwatered
Diseases
Root rot in poorly drained soil, generally very disease resistant
Troubleshooting Silver Thyme
What you'll see, why it happens, and what to do about it.
Leaves stippled with tiny yellow or bronze dots, fine webbing on undersides, plant looks dusty and dull
Likely Causes
- Spider mites (Tetranychus urticae) — thrive in hot, dry conditions above 85°F
- Low humidity and insufficient air circulation around the plant
What to Do
- 1.Blast the undersides of leaves with a strong stream of water to knock mites off
- 2.Apply insecticidal soap to affected foliage — NC State Extension notes it's one of the few options appropriate for culinary herbs
- 3.Space plants 12–15 inches apart and avoid crowding, which traps heat and makes conditions worse
Stems turning brown or black at the soil line, plant wilting even when soil is moist, roots look dark and mushy
Likely Causes
- Root rot from Pythium or Phytophthora spp. — triggered by waterlogged, poorly drained soil
- Overwatering in heavy clay or compacted soil with no drainage
What to Do
- 1.Pull the plant and inspect roots — cut away any black, soft sections with clean shears, then repot or replant in well-draining soil amended with coarse sand or perlite
- 2.Water only when the top inch of soil is dry; Silver Thyme is drought-tolerant once established and doesn't need frequent irrigation
- 3.If growing in a container, make sure the pot has drainage holes and never let it sit in a saucer of standing water
Pale, elongated new growth reaching toward light, weak stems that flop over, leaf color fading from silver-green to plain green
Likely Causes
- Insufficient light — Silver Thyme needs 6+ hours of direct sun daily
- NC State Extension's IPM guidance notes that sun-loving plants placed in shade are weak and more susceptible to pests
What to Do
- 1.Move the plant to a spot with full sun exposure — south or west-facing is usually best
- 2.If growing indoors or under cover, supplement with a grow light positioned 4–6 inches above the foliage
- 3.Cut back the leggy growth by about one-third to encourage compact, bushy regrowth once light conditions improve
Frequently Asked Questions
How long does silver thyme take to grow from seed?▼
Can you grow silver thyme in containers?▼
What does silver thyme taste like compared to regular thyme?▼
Is silver thyme good for beginner gardeners?▼
When should I plant silver thyme seeds?▼
Does silver thyme come back every year?▼
Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
- ExtensionNC State Extension
- USDAUSDA FoodData Central
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.