Hyssop

Sun

Full sun; tolerates light shade but flowers less and grows more loosely.

Water

Water regularly while establishing, allowing the soil surface to dry between waterings. Established plants tolerate drought and need watering mainly during prolonged dry spells.

Soil

Well-drained, lean to moderately fertile soil, preferably neutral to alkaline. Avoid heavy, persistently wet soil, especially in winter.

Height

1.5-2 ft (0.45-0.6 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Summer to early autumn; usually blue-purple, with pink- and white-flowered forms also available.

Foliage

Small, narrow, opposite, dark green leaves with a strong herbal scent. Evergreen or semi-evergreen in mild winters, but often loses its leaves in colder climates.

Growth

Moderate

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Heat tolerant
• Low allergen
• Fragrant
• Edible

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.2 ft (0.37 m)

3. After 2 years

   1.5 ft (0.45 m)

4. After 3 years

   1.7 ft (0.53 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Moderate

• Plant in a sunny position with sharp drainage; use a raised bed if your soil stays wet.
• Water new plants through their first growing season, letting the surface dry between soakings.
• Avoid rich feeding; excess nitrogen encourages soft, floppy growth.
• Keep mulch clear of the woody crown; gravel is useful where winter damp is a problem.
• Take cuttings to replace old plants that become woody and sparse.

Pruning. In spring, once new growth is visible, shorten stems to make a compact plant, leaving leafy growth below each cut. Lightly trim spent flower spikes after flowering, but avoid cutting hard into bare old wood or pruning heavily before winter.

Snip young leaves and tender shoot tips from spring through summer, preferably before flowering for culinary use. Pick healthy, fully opened leaves and use sparingly because the flavour is strong and bitter; harvest flowering sprigs as the first flowers open if you want to dry them.

Early spring

Sow seed under cover in a free-draining seed mix.

Spring

Trim established plants once fresh growth shows, removing winter-damaged stems.

Late spring

Plant out hardened-off young plants after severe frosts, spacing them about 1-1.5 ft (0.3-0.45 m) apart.

Summer

Harvest leafy tips sparingly and leave plenty of flower spikes for bees.

Late summer

Take non-flowering, semi-ripe cuttings and lightly trim faded flowers.

Autumn

Remove unwanted seedlings and check that water drains away from the crown.

• Clip into a low edging around herb beds or a potager.
• Repeat small groups through a sunny border with lavender and yarrow for blue-purple summer colour.
• Plant beside paths where brushing the foliage releases its scent.
• Use in gravel gardens with thyme and sage for a compact, drought-tolerant planting.
• Grow in a well-drained container near the kitchen for occasional harvesting.

Garden styles it suits: Herb parterre, Potager (kitchen garden), Cottage garden, Mediterranean, Dry gravel garden and Pollinator garden.

Plant it with: Lavender, Common thyme, Common sage, Oregano, Yarrow and Catmint.

Wildlife: The nectar-rich flowers attract honeybees, bumblebees and other pollinating insects, including butterflies. Leave some flower spikes uncut throughout summer.

• Root and crown rot in wet soil: improve drainage, keep the crown clear of mulch and replace badly affected plants.
• Woody, open growth with age: trim lightly each spring and replace declining plants with rooted cuttings.
• Weak flowering or floppy stems: provide more sun and stop high-nitrogen feeding.
• Unwanted self-sown seedlings: remove faded spikes before seed ripens or pull seedlings while small.

Leaves and flowers are used in small culinary quantities by people and are not known to be toxic at those amounts. Concentrated hyssop essential oil can cause serious poisoning, including seizures, and should not be swallowed; avoid medicinal use during pregnancy or with a seizure disorder. Reliable safety information for cats, dogs and horses is limited, so do not assume the plant is safe for deliberate feeding, and keep essential oil away from animals.

• Anise hyssop (Agastache foeniculum)

  Anise hyssop has broad, toothed, often heart-based leaves with an anise scent and usually grows taller. True hyssop has small, narrow leaves and woody lower stems.

• English lavender (Lavandula angustifolia)

  Lavender has grey-green foliage and flower spikes held on long, mostly leafless stalks. Hyssop has greener leaves and flowers clustered along the upper portions of leafy stems.

Hyssopus comes from the ancient Greek hyssopos, a name used for an aromatic herb, while officinalis indicates a plant traditionally kept for medicinal use.

Propagation. Sow seed in spring, covering it lightly, or take softwood cuttings in late spring and semi-ripe cuttings in late summer. Cuttings preserve the flower colour and growth habit of the parent plant; seedlings may vary.

Accepted botanical name

Hyssopus officinalis

In the US and Canada

Introduced in Canada and the lower 48 states.

Sources: GBIF (CC BY 4.0) and USDA PLANTS. The care and design notes are LandscapeGPT's own.