Overwintering Salvias: How to Protect Your Salvias from Frost

Introduction

Overwintering salvias is essential for keeping these beautiful flowering perennials healthy and ensuring they return in full bloom the following season. While some hardy salvias can survive winter outdoors, tender salvias need extra protection from frost, especially in colder regions.

Instead of letting your salvias die in the cold, you can mulch them, bring them indoors, or store them in a greenhouse to keep them safe until spring.

In this comprehensive guide, we’ll cover:
✅ The best methods for overwintering salvias
✅ How to protect both hardy and tender varieties
✅ The right way to prune and prepare salvias for winter
✅ Common mistakes to avoid
✅ Expert tips for ensuring strong regrowth in spring

Why Overwinter Salvias?

Salvias are long-flowering perennials, but many species are not frost-hardy and need protection in winter. Overwintering salvias allows you to:
🌱 Preserve mature plants and save money on replacements.
🌸 Encourage bigger and healthier blooms the following year.
❄️ Prevent frost damage and plant loss in colder climates.

💡 Tip: If your region experiences temperatures below 5°C (41°F), you should protect or move tender salvias indoors.

Which Salvias Need Overwintering?

1. Hardy Salvias (Can Stay Outdoors with Minimal Protection)

🌿 These salvias tolerate frost but benefit from mulching in cold winters.
✅ Salvia nemorosa (Balkan Clary)
✅ Salvia sylvestris (Wood Sage)
✅ Salvia x superba (Perennial Meadow Sage)
✅ Salvia officinalis (Common Sage)

💡 Tip: Hardy salvias should be cut back in early spring, not autumn.

2. Tender Salvias (Must Be Protected from Frost)

🌿 These salvias are not frost-hardy and must be moved indoors or heavily mulched.
✅ Salvia elegans (Pineapple Sage)
✅ Salvia guaranitica (Anise-scented Sage)
✅ Salvia leucantha (Mexican Bush Sage)
✅ Salvia patens (Gentian Sage)

💡 Tip: If temperatures drop below freezing (-2°C or lower), tender salvias must be overwintered indoors.

Best Methods for Overwintering Salvias

1. Protecting Hardy Salvias Outdoors (Best for Frost-Tolerant Varieties)

✅ Step 1: Apply Mulch for Winter Protection

• Cover the base with 5-10 cm (2-4 inches) of compost, bark, or straw to insulate roots.

✅ Step 2: Reduce Watering in Winter

• Avoid soggy soil—water only when necessary in dry conditions.

✅ Step 3: Avoid Cutting Back in Autumn

• Leave old stems intact to protect the crown from frost.
• Cut back in early spring when new shoots appear.

💡 Tip: If your region has very cold winters (-5°C or lower), wrap salvias in horticultural fleece for extra insulation.

2. Bringing Tender Salvias Indoors (Best for Potted Plants & Tropical Varieties)

✅ Step 1: Move Salvias Indoors Before Frost

• Bring tender salvias inside before temperatures drop below 5°C (41°F).

✅ Step 2: Choose a Suitable Location

• Store in a cool, bright place (5-10°C / 41-50°F) such as:
  • A greenhouse or cold frame
  • A bright garage or conservatory
  • An unheated porch

✅ Step 3: Reduce Watering

• Water only when the soil is dry to prevent rot.

✅ Step 4: Lightly Prune to Maintain Shape

• Remove any damaged or leggy growth, but avoid heavy pruning until spring.

💡 Tip: Keep salvias away from direct heat sources like radiators, which cause leaf drop.

3. Storing Salvias Dormant (For Large Plants with No Indoor Space)

✅ Step 1: Dig Up and Store the Roots

• If space is limited, lift the plant and shake off excess soil.

✅ Step 2: Trim Back the Foliage

• Cut stems down to 15 cm (6 inches).

✅ Step 3: Store in a Frost-Free Location

• Keep in a box filled with dry compost or sawdust at 5-10°C (41-50°F).

✅ Step 4: Check Monthly for Mold or Dryness

• Mist lightly if the roots dry out, but avoid overwatering.

💡 Tip: In March or April, pot up stored salvias and gradually reintroduce them to warmth and light.

4. Overwintering Salvias in a Greenhouse (Best for Mild Winters)

✅ Step 1: Move Potted Salvias into a Greenhouse

• A heated greenhouse keeps salvias growing slowly.
• An unheated greenhouse needs extra insulation.

✅ Step 2: Reduce Watering

• Water only once a month to prevent root rot.

✅ Step 3: Insulate if Temperatures Drop Below Freezing

• Use horticultural fleece or bubble wrap around pots for added protection.

💡 Tip: Keep the greenhouse well-ventilated to prevent mold and mildew.

When to Bring Salvias Back Outside in Spring

✅ March – April: Start watering more regularly to encourage new growth.
✅ April – May: Move plants outdoors gradually to harden them off.
✅ After the last frost: Replant in borders, containers, or raised beds.

💡 Tip: Feed salvias with a balanced fertilizer when replanting to boost flowering.

Common Mistakes to Avoid When Overwintering Salvias

🚫 Cutting back hardy salvias too early – Wait until early spring to prune.
🚫 Overwatering dormant salvias – This leads to root rot.
🚫 Leaving tender salvias outside in frost – Move them indoors or to a sheltered space.
🚫 Forgetting to check stored salvias – Inspect monthly for mold or dryness.

💡 Tip: If salvias look weak in spring, repot them in fresh compost and gradually reintroduce to sunlight.

Final Tips for Successful Overwintering

🌡 Monitor temperatures – Salvias need cool but frost-free conditions.
🏡 Choose the right method – Some salvias need mulching, others require indoor storage.
💦 Water sparingly – Most overwintered salvias need minimal moisture.
🌞 Provide light where needed – Houseplants still need indirect sunlight.
🌱 Check plants monthly – Prevent rot, mold, or dehydration.

💡 Tip: If overwintering in raised beds, use horticultural fleece for extra warmth.

Conclusion

Overwintering salvias is a simple but essential step to protect them from frost and ensure vibrant, long-lasting blooms next season.

By using mulching, indoor storage, or greenhouse protection, you can successfully preserve salvias over winter and enjoy strong regrowth in spring!