annual

Hoary Basil

Ocimum americanum

The Story

Plant Bio

Ocimum americanum, commonly known as hoary basil, is an erect, branching annual or short-lived perennial subshrub with a slender, upright form. The greyish-green to green ovate leaves are strongly aromatic, releasing a sweet spicy, clove, or lemon scent when crushed.

The plant produces terminal racemes of white to pale lavender flowers with hairy calyces throughout summer and fall. Unlike common sweet basil, this species features sparsely hairy foliage with cuneate bases and entire to slightly toothed margins.

Uses & Benefits:

Features delicate white to pale lavender flower spikes rising above dense, greyish-green foliage.

Highly aromatic leaves are used for culinary and cultural purposes, offering a sweet spicy, clove, or lemon scent.

Attracts native bees, honeybees, and generalist pollinators to the garden with its nectar-rich blooms.

Essentials

At a Glance

Plant Type

Annual

Height

24"

Width

16"

Light

Full Sun

Zones

9, 10

Water

Moderate

Humidity

High

Lifespan

Annual (Perennial in Zones 10-12)

Native To

Africa, Indian subcontinent, China, Southeast Asia

Toxicity

Non-toxic (essential oils may cause mild skin irritation)

Bloom period

Summer – Fall

In flower about 6 months of the year

Planting

How to Grow

Sow seeds indoors 6 weeks before the last expected spring frost, or direct sow in the garden once soil temperatures exceed 60°F.
Select a planting site in full sun with fertile, well-draining sandy loam or loam with a neutral pH.
Space plants 8 to 12 inches apart to ensure adequate air circulation and prevent fungal diseases.
Water regularly to keep the soil evenly moist but never waterlogged, allowing the top inch of soil to dry out between waterings.

Pro Tip

Pinch back the growing tips every few weeks during active growth to promote a bushy habit and delay flowering; cutting back into old, leafless woody stems prevents regrowth.

Keep It Thriving

Care Guide

Do

Pinch off flower buds as they appear to prolong the harvesting period and maintain foliage quality.
Provide excellent drainage to prevent root rot and other soil-borne fungal pathogens.
Apply a light organic fertilizer every 4 to 6 weeks if growing in containers.

Don't

Do not overwater or plant in heavy, compacted clay soils that retain standing water.
Do not cut back into old, woody, leafless stems when pruning, as this prevents regrowth.
Do not apply high-nitrogen fertilizers, which reduce the concentration of aromatic essential oils.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Harvest
Pest Check
Pinch
Plant

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Herb GardensContainersBorder EdgingPollinator Gardens

Companion Plants

Solanum lycopersicum Tagetes

Multiply

Propagation Methods

Good to Know

Common Questions

Hoary Basil questions

What zones can Hoary Basil grow in?

Hoary Basil is hardy in USDA Zones 9–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

When does Hoary Basil bloom?

Hoary Basil typically blooms in summer through fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Hoary Basil need full sun?

Hoary Basil does best in full sun (6+ hours).

Is Hoary Basil drought tolerant?

Yes — once established (usually after the first full season), Hoary Basil handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.