Repotting guide

When & how to repot Cotton Lavender (Santolina chamaecyparissus)

Also called Cotton Lavender, Lavender Cotton, Santolina.

More about cotton lavender

About Cotton Lavender

Santolina chamaecyparissus · also called Cotton Lavender, Lavender Cotton · herb

Santolina chamaecyparissus is a compact, aromatic, evergreen subshrub native to rocky, dry terrain across the western and central Mediterranean basin, including Spain, France, Italy, and North Africa. It is prized for its finely divided, silver-grey, intensely fragrant foliage and cheerful, bright yellow, button-like flowerheads borne on erect stems in midsummer. The single most important care fact is that it must have sharply drained, lean soil in full sun; rich or wet soil causes the plant to become floppy, woody at the centre, and prone to root rot. Santolina is not listed by the ASPCA on its toxic plant lists, but the essential oil contains linalool and camphor which may be irritating to pets in large quantities; treat as mildly-toxic.

Mature size: 50–75 cm tall and 60–90 cm wide; dwarf cultivars such as 'Nana' reach 25 cm.

Watch for — Woody, open centre after several years: Plants become woody and open in the middle without annual pruning. Cut back hard to within a few centimetres of old wood immediately after flowering to maintain a dense, compact mound.

How to tell cotton lavender needs repotting

Repotting on a calendar is less reliable than reading the plant. For cotton lavender, 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 cotton lavender

Every 2–3 years, into bone-dry mix. Cotton Lavender's growth habit — dense, rounded, evergreen subshrub with finely divided, silver-grey, aromatic foliage. — sets the pace. Santolina chamaecyparissus is a compact, aromatic, evergreen subshrub native to rocky, dry terrain across the western and central Mediterranean basin, including Spain, France, Italy, and North Africa. It is prized for its finely divided, silver-grey, intensely fragrant foliage and cheerful, bright yellow, button-like flowerheads borne on erect stems in midsummer. The single most important care fact is that it must have sharply drained, lean soil in full sun; rich or wet soil causes the plant to become floppy, woody at the centre, and prone to root rot. Santolina is not listed by the ASPCA on its toxic plant lists, but the essential oil contains linalool and camphor which may be irritating to pets in large quantities; treat as mildly-toxic.

What size pot to step cotton lavender up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Cotton Lavender 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 cotton lavender

Spring or summer, while cotton lavender 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 cotton lavender

Repot dry. Do not water cotton lavender 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 poor to moderately fertile, sharply drained, neutral to alkaline 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 cotton lavender 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 cotton lavender 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 cotton lavender

Cotton Lavender wants poor to moderately fertile, sharply drained, neutral to alkaline. Sandy, rocky, or gritty soils are ideal; add horticultural grit to clay soils. Rich, fertile soil produces excessive soft growth and increases disease susceptibility. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting cotton lavender — frequently asked questions

How often should you repot cotton lavender?

Every 2–3 years, into bone-dry mix for cotton lavender. Repot cotton lavender every 2–3 years into a snug pot of poor to moderately fertile, sharply drained, neutral to alkaline, 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 cotton lavender need?

When is the best time of year to repot cotton lavender?

Should you water cotton lavender after repotting?

No — not straight away. Repot cotton lavender 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 cotton lavender after repotting?

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