Shrub
How to grow hypericum (St John's wort)
Hypericum 'Hidcote' / H. calycinum
Shrubby hypericums grow in almost any UK soil that drains, in sun or part shade, and are planted from October to March. Choose by job: 'Hidcote' is a well-behaved flowering shrub for a border, while rose of Sharon (H. calycinum) is a spreading ground cover for banks and dry shade that should be kept away from beds and lawns. Both flower on new growth from June to September, so cut them back in March.
- Hardiness
- Fully hardy
- Position
- Sun to part shade
- Soil
- Most soils; free-draining
- Ideal pH
- 6.0 to 7.5
- Water
- Low
- Feeding
- Light feeder
Sowing and planting hypericum (St John's wort)
WhenPlant Oct to Mar; flowers Jun to Sep; cut back Mar
Starting off
Plant pot-grown stock Oct to Mar, or bare-root H. calycinum Nov to Mar for banks and under trees. Propagate 'Hidcote' by 10 cm softwood cuttings in Jun or semi-ripe in Aug at 18°C; H. calycinum by lifting rooted suckers in Mar, when a single plant gives a dozen. Do not plant H. calycinum near borders or lawns, as it invades.
Spacing and planting
H. 'Hidcote' makes a 1.2 to 1.5 m by 1.5 m dome; ground-cover H. calycinum stays at 30 to 45 cm tall and runs indefinitely by suckers. Plant 'Hidcote' 1.2 m apart; H. calycinum at 45 cm spacing (5 plants per square metre) for a closed carpet within 2 years. 'Hidcote' is passable in a 40 cm pot; H. calycinum is not a container plant.
Varieties worth growing
- 'Hidcote'
- The best garden shrub of the group: a 1.2 to 1.5 m dome with large golden saucers from June to September, and it does not sucker.
- H. calycinum (rose of Sharon)
- Evergreen carpet 30 to 45 cm high for banks and dry shade under trees. Spreads by runners, so plant it only where it can be contained.
- H. × inodorum Magical series
- Small yellow flowers followed by red, pink or cream berries on 80 cm bushes, bred for cutting and for better resistance to rust.
- H. androsaemum (tutsan)
- British native for shade, about 75 cm, with berries that turn from red to black. Self-seeds freely.
- H. olympicum
- Low, grey-leaved alpine species 25 cm high with large lemon or gold flowers; for a rock garden, wall top or gravel in full sun.
Month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Plant in mild spells.
- February
Plant. Bare-root rose of Sharon goes in now for banks.
- March
Prune 'Hidcote' by a third to a half. Shear rose of Sharon to 5 to 10 cm. Lift rooted suckers to make new plants. Last planting.
- April
Mulch after pruning. Water anything planted this spring.
- May
Nothing to do. Chop back runners of rose of Sharon at the edges.
- June
Flowering begins. Softwood cuttings of 'Hidcote'.
- July
Flowering. Water first-year plants in drought.
- August
Semi-ripe cuttings of 'Hidcote'. Check leaf undersides for rust.
- September
Last flowers. Cut berried stems of H. × inodorum for the house. Edge round ground cover again.
- October
Planting season opens.
- November
Plant. Rake fallen rusted leaves from under the plants.
- December
Nothing to do.
Feeding hypericum (St John's wort)
A light feeder. In ordinary soil it needs nothing, and nitrogen gives leaf in place of flower. The exceptions are ground cover competing with tree roots, a plant cut hard back, and a shrub in a pot.
Low, a tough ground-cover shrub.
Feeding plan
Planting
5 g per litre of root ball on the roots: 10 g for a 2 litre pot, 15 g for a 3 litre pot.
Every year, plants in ordinary soil
No fertiliser
None.
March, rose of Sharon under trees, after shearing
50 g/m², half the label rate, scattered over the cut stems, then 2 to 3 cm of garden compost on top. Once a year.
March, after cutting an old 'Hidcote' down to 15 to 30 cm
100 g/m² once: about 180 g for a shrub 1.5 m across (1.8 m²), watered in and mulched.
'Hidcote' in a pot
5 g per litre at potting (125 g for a 40 cm pot of about 25 litres), then 2 g per litre (50 g) on the surface each March.
Signs to watch
Yellowing between the veins on older leaves of H. calycinum under trees
Magnesium and general hunger from root competition and dry shade
Epsom salts drench and a compost mulch
Few flowers on lush 'Hidcote'
Excess nitrogen or shade
No feeding, more sun, prune in Mar
Pests, diseases and problems
Orange pustules under the leaves with yellow or red blotches above, followed by leaf fall
Hypericum rust, commonest on H. calycinum, H. × inodorum and tutsan
Shear affected ground cover to the ground in March and rake out every scrap of old leaf. On shrubs, cut out the worst stems and replace badly affected plants with a more resistant kind.
Rose of Sharon brown and ragged by the end of winter
Cold wind and frost on semi-evergreen foliage
Normal in a hard winter. Shear or mow it to 5 to 10 cm in March and fresh growth covers it within weeks.
Stem tips of 'Hidcote' dead and leafless in spring
Frost dieback
Cut back to live buds when you prune in March; it flowers on the new shoots, so nothing is lost.
Shoots coming up in the lawn, through neighbouring plants and under fences
The runners of H. calycinum
Chop round the patch with a spade twice a year and pull the severed runners, or sink a 30 cm deep edging. Use 'Hidcote' in mixed borders in its place.
Seedlings appearing all over nearby beds
Tutsan and H. × inodorum seeding from their berries
Cut the berried stems for the house before they ripen fully, and hoe off seedlings while small.
Pruning
Pruning and care
Both flower on the current year's growth, so cut back in Mar as buds break: shorten 'Hidcote' by a third to half, cutting to outward buds, and shear H. Hard renovation to 15 to 30 cm in Mar is reliable. No staking or winter protection; the semi-evergreen foliage may drop in a hard winter and regrows.
Good to knowCut back in spring; yellow flowers then berries. Can sucker.
Growing in pots
'Hidcote' and the berrying H. × inodorum kinds will grow in a 40 cm pot of loam-based compost for a few years, though they are better in the ground. Water regularly from May to September and cut back in March as usual. H. olympicum suits a shallow pan of gritty compost in full sun. Rose of Sharon is not a container plant: it wants to run, and in a pot it is a thin, untidy thing.
Common questions
Is hypericum invasive?
Rose of Sharon (H. calycinum) is: it spreads indefinitely by underground runners and will invade lawns and borders. Tutsan seeds itself around. 'Hidcote' does neither and stays where it is planted, so it is the one to choose for a mixed border.
When do I cut back hypericum?
Cut back in March, as the buds begin to break. Shorten 'Hidcote' by a third to a half, to outward-facing buds, and shear or mow rose of Sharon to 5 to 10 cm. Both flower on the current year's growth, so spring pruning does not cost any flowers.
Does hypericum grow in shade?
Yes, rose of Sharon and tutsan grow well in shade, including dry shade under trees, which is their main use. 'Hidcote' tolerates part shade but flowers most heavily with sun for at least half the day.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.