Repotting guide

When & how to repot May Night Salvia (Salvia nemorosa 'Mainacht')

Also called May Night salvia, May Night sage.

More about may night salvia

About May Night Salvia

Salvia nemorosa 'Mainacht' · also called May Night salvia, May Night sage · flowering

May Night is a compact, clump-forming hardy perennial sage prized for dense spikes of deep indigo-violet flowers from late spring into summer. The 1997 Perennial Plant of the Year, it thrives in full sun and lean, well-drained soil, draws bees and butterflies, and rebounds with a second flush after a hard deadheading shear.

Mature size: About 45-60 cm tall and 30-45 cm wide (18-24 in tall, 12-18 in wide).

Watch for — Crown and root rot: Triggered by wet, poorly drained soil, especially over winter. Plant in sharply drained soil and never let the crown sit in standing water.

How to tell may night salvia needs repotting

Repotting on a calendar is less reliable than reading the plant. For may night salvia, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot may night salvia

Every 2–3 years, into bone-dry mix. May Night Salvia's growth habit — compact, upright, clump-forming herbaceous perennial with aromatic grey-green basal foliage and erect flower spikes held above the mound. — sets the pace. May Night is a compact, clump-forming hardy perennial sage prized for dense spikes of deep indigo-violet flowers from late spring into summer. The 1997 Perennial Plant of the Year, it thrives in full sun and lean, well-drained soil, draws bees and butterflies, and rebounds with a second flush after a hard deadheading shear.

What size pot to step may night salvia up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. May Night Salvia stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot may night salvia

Spring or summer, while may night salvia is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting may night salvia

Repot dry. Do not water may night salvia for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty lean, gritty, sharply free-draining loam ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set may night salvia at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep may night salvia completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for may night salvia

May Night Salvia wants lean, gritty, sharply free-draining loam. Tolerates average to poor fertility and prefers neutral to slightly alkaline pH. Avoid rich, moisture-retentive ground; add grit or sand to heavy clay to guarantee drainage. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting may night salvia — frequently asked questions

How often should you repot may night salvia?

Every 2–3 years, into bone-dry mix for may night salvia. Repot may night salvia every 2–3 years into a snug pot of lean, gritty, sharply free-draining loam, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does may night salvia need?

When is the best time of year to repot may night salvia?

Should you water may night salvia after repotting?

No — not straight away. Repot may night salvia into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise may night salvia after repotting?

Not immediately. Wait about 3 weeks after repotting may night salvia. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.