Blackcurrant sage (Salvia microphylla 'Blackcurrant') is an aromatic perennial herb belonging to the mint family (Lamiaceae). It is prized for its distinctive blackcurrant-scented foliage — the leaves release a rich, fruity, berry-like fragrance when crushed or lightly brushed.

The plant produces small, vivid red to magenta tubular flowers, typically blooming from late spring through to early autumn. These blooms are highly attractive to pollinators, including bees, butterflies, and hummingbirds where they occur, making this plant a valuable addition to any wildlife-friendly garden.

Blackcurrant sage grows to approximately 60–120 cm in height with a spreading, bushy habit. It is drought-tolerant once established, making it a resilient, low-maintenance choice for herb gardens, mixed borders, flower beds, and containers. Beyond its ornamental appeal, the leaves and flowers are occasionally used in teas, desserts, and savoury culinary dishes, where their fruity aroma adds a unique and appealing flavour. Its fragrant foliage also lends itself to use in potpourri and herbal crafts.

How To Grow

How to Grow Blackcurrant Sage

Choosing a Location

Blackcurrant sage thrives in a position that receives full sun for at least six hours per day. It will tolerate partial shade but tends to produce fewer flowers in shadier spots. Choose a sheltered spot where it is protected from cold, drying winds in winter.

Soil Preparation

This plant prefers well-drained soil with a pH of 6.0–7.5. Sandy or loamy soil is ideal. Heavy clay soils should be amended with grit, sharp sand, or organic compost to improve drainage before planting. Waterlogged conditions will cause root rot.

Sowing from Seed

Blackcurrant sage can be started from seed indoors at a soil temperature of 15–24°C. Sow seeds 0.5 cm deep in moist seed compost. Germination typically takes 14–21 days. Once seedlings are large enough to handle and all risk of frost has passed, harden them off before transplanting outdoors.

Transplanting and Spacing

Space plants 60 cm apart in all directions to allow adequate airflow and room for the spreading habit. Plant so the crown sits level with the soil surface. Water in well after planting.

Propagation from Cuttings

The most reliable method of propagation is by softwood cuttings taken in late spring or early summer. Take 10–15 cm cuttings from healthy, non-flowering shoots, remove the lower leaves, and insert into moist cutting compost. Place in a warm, bright location — roots should form within three to four weeks.

Watering

Water regularly for the first few weeks after planting to establish roots. Once established, blackcurrant sage is drought-tolerant and only requires occasional deep watering during extended dry spells. Allow the soil to dry slightly between waterings. Avoid overwatering.

Feeding

Apply a balanced, slow-release fertiliser in spring to support healthy growth. Avoid high-nitrogen feeds, which encourage leafy growth at the expense of flowers. An annual top-dressing of garden compost is sufficient for most established plants.

Pruning

Deadhead spent flowers regularly to encourage continuous blooming. In early spring, cut the plant back by approximately one-third to maintain a compact, bushy shape and prevent it from becoming leggy. In colder climates, wait until the risk of hard frost has passed before cutting back, as the old stems can offer some frost protection to the crown.

Winter Care

In areas that experience frost, apply a generous layer of mulch (bark chips, straw, or well-rotted compost) around the base of the plant to insulate the roots. Top growth may die back in hard winters, but plants will typically reshoot from the base in spring.

Container Growing

Blackcurrant sage grows well in containers filled with a free-draining compost mix. Ensure pots have adequate drainage holes. Container plants dry out faster and will need more regular watering and feeding than those in open ground.

Harvesting

Harvesting Blackcurrant Sage

When to Harvest

Leaves can be harvested throughout the growing season once the plant is well established — typically from late spring through to early autumn. For the most intense aroma and flavour, pick leaves in the morning after any dew has dried, but before the full heat of the day sets in. This is when the concentration of essential oils in the foliage is at its peak.

Flowers can be harvested as soon as they are fully open, usually from late spring onwards and continuing in flushes until early autumn.

Harvesting Leaves

Use clean, sharp scissors or pruners to snip off individual leaves or short stem tips just above a leaf node. This encourages branching and fresh new growth. Never remove more than one-third of the plant's foliage at any one time, as this can stress the plant and reduce its overall vigour and flowering potential.

Harvesting Flowers

Cut flower stems just above the next set of leaves. Regular removal of open flowers (deadheading) not only provides a harvest but also extends the flowering season by encouraging the plant to produce new blooms.

Drying Leaves

Spread leaves in a single layer on a clean tray in a warm, well-ventilated, shaded location. Alternatively, tie small bunches of stems together and hang them upside down in a dry, dark area with good airflow. Once fully dry and crisp, store in an airtight container away from light and heat. Properly dried leaves retain their fragrance and flavour for up to 12 months.

Drying Flowers

Bundle stems with several open flowers and hang upside down in a warm, dark, airy space. Once dried, they can be used in potpourri or floral arrangements.

Using Your Harvest

• Tea: Steep a few fresh or dried leaves in boiling water for 5–8 minutes for a fruity, fragrant herbal infusion.
• Culinary uses: Add fresh leaves sparingly to fruit salads, desserts, sorbets, or savoury dishes where a subtle berry note is welcome. The flowers are also edible and make attractive garnishes.
• Aromatics: Dried leaves and flowers are excellent in potpourri, herbal sachets, and scented pillows.

Common Problems

Common Problems with Blackcurrant Sage

Pests

• Aphids — Soft-bodied insects that cluster on new shoots and under leaves, causing distortion and sticky residue. Blast off with a strong jet of water or treat with insecticidal soap or diluted neem oil.
• Spider mites — Tiny mites that thrive in hot, dry conditions, causing stippled, yellowing foliage and fine webbing. Increase humidity around the plant and apply neem oil or insecticidal soap.
• Whitefly — Can infest plants grown under cover. Use yellow sticky traps or introduce biological controls where appropriate.
• Vine weevil — Grubs can attack roots, especially in container-grown plants. Check roots periodically and use biological nematode treatments if grubs are found.

Diseases

• Powdery mildew — A white, powdery fungal coating on leaves, encouraged by poor airflow and dry roots combined with humid air. Improve spacing, water at the base, and remove affected leaves.
• Root rot — Caused by waterlogged soil or overwatering. Ensure excellent drainage; allow the soil to dry slightly between waterings.
• Botrytis (grey mould) — Can affect stems and leaves in cool, damp conditions. Remove affected material and improve ventilation.

Environmental Issues

• Legginess — In low light or without regular pruning, plants become straggly. Cut back by one-third each spring or after the main flush of flowering to maintain a compact, bushy form.
• Winter dieback — In colder areas, top growth may die back after hard frosts. Mulch the root zone well; the plant typically reshoot from the base in spring.
• Overwatering — A common mistake, especially with container plants. This species strongly prefers drying out slightly between waterings.