Repotting guide

When & how to repot Coris-Leaved St John's Wort (Hypericum coris)

Also called Coris-leaved St John's wort, Heath-leaved St John's wort.

More about coris-leaved st john's wort

About Coris-Leaved St John's Wort

Hypericum coris · also called Coris-leaved St John's wort, Heath-leaved St John's wort · flowering

Hypericum coris is a compact, mound-forming, semi-evergreen subshrub native to the southwestern and central Alps and northern Italy, where it colonises sunny limestone rocks and scree at elevations up to 2,000 m. It produces whorls of narrow, heath-like leaves on wiry stems and bears clusters of small golden-yellow, cup-shaped flowers in summer, making it an elegant choice for rock gardens and gravel beds. The single most important care point is sharp drainage — permanently wet soil will kill it, particularly in winter. Per the ASPCA, Hypericum (St John's wort) is toxic to cats, dogs, and horses, with hypericin as the toxic principle.

Mature size: Typically 20–30 cm tall and 30–40 cm wide.

Watch for — Root and crown rot: The most common cause of failure; results from waterlogged soil especially in winter — ensure very sharp drainage and avoid overhead watering.

How to tell coris-leaved st john's wort needs repotting

Repotting on a calendar is less reliable than reading the plant. For coris-leaved st john's wort, watch for these signs:

Roots spiralling thickly out of the drainage holes or pushing the whole plant up out of the pot.
The pot is so packed that water runs straight through in seconds and barely wets the soil.
It has split a plastic pot, or the rootball is a solid mass with almost no soil left when you slide it out.
Growth and (for coris-leaved st john's wort) flowering have clearly stalled despite good light and feeding — but remember this plant likes being snug, so a little crowding alone is not a reason to repot.

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 coris-leaved st john's wort

Only every 2–4 years, when genuinely crowded. Coris-Leaved St John's Wort is one of the plants that genuinely prefers a snug pot — it grows and flowers better with its roots a little restricted, so resist the urge to repot it on schedule. Low, mound-forming, semi-evergreen subshrub with erect wiry stems and whorled linear leaves..

What size pot to step coris-leaved st john's wort up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Coris-Leaved St John's Wort positively prefers a snug pot: it flowers and grows better when the roots are a little restricted. The single biggest repotting mistake here is over-potting — dropping coris-leaved st john's wort into a pot two or three sizes up. All that surplus soil holds water the small root system cannot use, stays cold and wet, and rots the roots within weeks. When in doubt, choose the smaller pot.

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 coris-leaved st john's wort

Early spring, just as new growth restarts, is the ideal window for coris-leaved st john's wort. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting coris-leaved st john's wort

Confirm it actually needs it. Slide coris-leaved st john's wort out and check the roots. Only continue if it is genuinely packed — this plant prefers a snug pot, so if there is still soil and room, put it straight back.
Pick a pot only one size up. Choose a pot just 2–3 cm wider with good drainage. Resist anything bigger; over-potting is the main killer here.
Ease it out gently. Water lightly the day before, then tip coris-leaved st john's wort out, supporting the base. Tease the outer roots free only enough to stop them circling.
Repot at the same depth. Add a layer of fresh well-drained to very well-drained; sand, loam, or chalk, set the plant so the soil line sits exactly where it did before, and backfill around the sides, firming lightly.
Settle it in. Water once to settle the soil, then let it sit. Hold off on more water until the top of the soil dries — fresh soil around a small root system stays wet for a while.

Aftercare

Because the new soil holds more water than the old crammed rootball did, ease right back on watering — let the top of the soil dry before you water coris-leaved st john's wort again, or you will rot the roots in the very pot you just moved it to. Keep it out of harsh direct sun for a fortnight. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for coris-leaved st john's wort

Coris-Leaved St John's Wort wants well-drained to very well-drained; sand, loam, or chalk. Add grit or gravel to improve drainage; naturally grows in calcareous scree so tolerates alkaline to neutral pH. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting coris-leaved st john's wort — frequently asked questions

How often should you repot coris-leaved st john's wort?

Only every 2–4 years, when genuinely crowded for coris-leaved st john's wort. Only repot coris-leaved st john's wort every 2–4 years, and only when it is genuinely root-bound — it flowers and grows best slightly crowded. Step up just one pot size in spring using well-drained to very well-drained; sand, loam, or chalk. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does coris-leaved st john's wort need?

When is the best time of year to repot coris-leaved st john's wort?

Does coris-leaved st john's wort like to be root-bound?

Yes — coris-leaved st john's wort genuinely flowers and grows best when slightly pot-bound, so do not rush to repot it. The mistake to avoid is over-potting into a much larger pot: the excess soil stays wet, the roots cannot use it, and the plant rots. Only repot every few years and only one snug size up.

Should you fertilise coris-leaved st john's wort after repotting?

Not immediately. Wait about 4 weeks after repotting coris-leaved st john's wort. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.