Repotting guide

When & how to repot Night-scented stock (Matthiola longipetala)

Also called Night-scented stock, Evening stock, Perfume plant, Gilly flower.

More about night-scented stock

About Night-scented stock

Matthiola longipetala · also called Night-scented stock, Evening stock · flowering

Night-scented stock is a fast-growing hardy annual whose small, purple or pale lilac flowers appear modest by day — petals fold inward in sunlight — but open wide at dusk, releasing an extraordinarily powerful, sweet fragrance. Sow directly into beds in full sun, water sparingly, and expect flowers within 6–8 weeks from seed.

Mature size: 20–45 cm tall (8–18 in), 15–30 cm spread (6–12 in)

Watch for — Overwatering and root rot: The most common problem in containers and poorly drained beds. Plants collapse suddenly at the stem base. Ensure sharply drained soil, water only when the surface is dry, and never allow pots to sit in water.

How to tell night-scented stock needs repotting

Repotting on a calendar is less reliable than reading the plant. For night-scented stock, 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 night-scented stock

Every 2–3 years, into bone-dry mix. Night-scented stock's growth habit — upright to spreading hardy annual with grey-green foliage; thin branching stems and small racemes of four-petalled flowers — sets the pace. Night-scented stock is a fast-growing hardy annual whose small, purple or pale lilac flowers appear modest by day — petals fold inward in sunlight — but open wide at dusk, releasing an extraordinarily powerful, sweet fragrance. Sow directly into beds in full sun, water sparingly, and expect flowers within 6–8 weeks from seed.

What size pot to step night-scented stock up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Night-scented stock 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 night-scented stock

Spring or summer, while night-scented stock 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 night-scented stock

Repot dry. Do not water night-scented stock 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 well-drained chalk, loam, or sand, ph 6.5–7.5 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 night-scented stock 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 night-scented stock 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 night-scented stock

Night-scented stock wants well-drained chalk, loam, or sand, ph 6.5–7.5. Thrives in poor to moderately fertile, sharply drained alkaline or neutral soils. Rich, moist soils produce leafy, lax plants with fewer flowers. Avoid compacted or waterlogged ground. Ideal on chalk, sandy, or gritty soils. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting night-scented stock — frequently asked questions

How often should you repot night-scented stock?

Every 2–3 years, into bone-dry mix for night-scented stock. Repot night-scented stock every 2–3 years into a snug pot of well-drained chalk, loam, or sand, ph 6.5–7.5, 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 night-scented stock need?

When is the best time of year to repot night-scented stock?

Should you water night-scented stock after repotting?

No — not straight away. Repot night-scented stock 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 night-scented stock after repotting?

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