Blue Spike

Anise Hyssop

Zone 6b Save Garden

🌱 90d to harvest Upright

Fragrant as a summer breeze, Blue Spike anise hyssop blooms with cool, violet-blue spires that carry a crisp anise-citrus perfume…

Crop Dates

Milestone	Date
Start Indoors	Mar 14th
Last Frost	Apr 25th
Transplant / Sow Outdoors	Jun 6th
Harvest Begins	Sep 4th
Harvest Ends	Oct 16th

Crop Details

Trait	Value
Days to Maturity	90
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	65
Min Soil Temp (°F)	55
Min Night Temp (°F)	50
Harden Off (days)	7

Recommended Companions

Rose Rhapsody Salvia

Rhapsody In Blue Salvia

Cherry Brandy Coneflower

Frequently Asked Questions

Why are my Blue Spike plants getting powdery white spots on the leaves, and what should I do?

Powdery mildew commonly appears on Blue Spike as a dusty white coating on leaf surfaces, often after warm days and cooler nights. Remove the worst affected leaves, improve airflow by spacing plants, and water at the soil line (not overhead). If it keeps spreading, spray with a labeled fungicide for powdery mildew and repeat according to the label every 5–10 days while conditions are favorable for the disease.

How often should I water Blue Spike during the main growing phase (after seedlings establish)?

After establishment, keep the soil evenly moist but not soggy—aim for about 1 inch of water per week, split into 2–3 waterings if it’s hot or windy. Check by feel 2 inches down: if it’s dry there, water; if it stays damp, hold off. During active growth, consistent moisture helps prevent stunted growth and leaf stress, especially in full sun.

When are Blue Spike ready to harvest, and how do I know?

Harvest Blue Spike when the flower spikes are fully formed and show strong blue color with buds opening from the bottom upward. If you wait until almost all buds are open, the stems tend to age faster in the vase—aim for the “bottom buds open, top still tightening” stage. You can expect about 90 days from sowing for harvest readiness, depending on temperature and sunlight.

Fragrant as a summer breeze, Blue Spike anise hyssop blooms with cool, violet-blue spires that carry a crisp anise-citrus perfume from garden air to the fingertips. Expect slender, upright flower spikes over a tidy mound of aromatic foliage, with a pleasantly crisp, herbal bite that shines in fresh bouquets and aromatic infusions. Grow Blue Spike for its long-lasting color and signature scent—ideal for attracting pollinators while adding a distinctive, anise-forward note to herbal blends and seasonal arrangements.

Sowing Tips

Transplant Conditions

Wait until soil reaches 55°F and nights stay above 50°F before moving outdoors. Harden off for 7 days first.

Expert Note

Start indoors for strongest blooms, then transplant after nights are reliably warm to avoid stalling young Agastache.