Shrub (ericaceous)
How to grow pieris
Pieris japonica / P. 'Forest Flame'
Pieris is grown for two things at once: white lily-of-the-valley flowers in March to May and bright red new leaves just after. Both are soft and early, so the site decides success. Plant in September to October or March to April in acid, moist soil (pH 4.5 to 6.0) in part shade, sheltered from cold wind and early morning sun, and be ready with fleece when frost is forecast in April. On alkaline soil grow it in a pot of ericaceous compost.
- Hardiness
- Fully hardy (red new growth frost-prone)
- Position
- Part shade, sheltered
- Soil
- Acid, humus-rich, moist
- Ideal pH
- 4.5 to 6.0
- Water
- Moderate to high; rainwater
- Feeding
- Light feeder
Sowing and planting pieris
WhenPlant Sep to Oct or Mar to Apr; flowers Mar to May; new growth Apr to May
Starting off
Plant pot-grown stock Sep to Oct or Mar to Apr; it is never sold bare-root. Propagate by 8 to 10 cm semi-ripe cuttings in Jul to Sep in a 50:50 mix of ericaceous compost and perlite at 18 to 20°C with bottom heat, rooting in 8 to 10 weeks; layering a low branch in Apr is easier for one plant.
Spacing and planting
P. japonica 'Forest Flame' reaches 2 to 3 m by 1.5 to 2 m in 10 to 15 years; dwarf 'Little Heath' stays at 60 cm by 80 cm. Plant 1.5 m apart in a wide hole no deeper than the rootball, with the top level with the soil, in a spot sheltered from early morning sun. Dwarf and medium types do very well in a 40 to 50 cm pot of ericaceous compost.
Varieties worth growing
- 'Forest Flame'
- The best known: new leaves open scarlet, fade through pink and cream to green. Large, 2 to 3 m in time, so give it room.
- P. japonica 'Mountain Fire'
- Deep red-bronze young growth on a slower, more compact plant to about 1.5 m, easier to place than 'Forest Flame'.
- P. japonica 'Little Heath'
- Dwarf, about 60 cm, with small white-edged leaves flushed pink when young; grown for foliage in pots and rarely flowers heavily.
- P. japonica 'Katsura'
- Glossy wine-red new leaves and rose-pink flowers; compact, to about 1 m, and tends to flush more than once in a season.
- 'Flaming Silver'
- Variegated: red new growth that matures green with a silver-white margin. Around 1.2 m, good in a pot.
Pieris month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Nothing to do. Flower buds are already showing as strings of beads.
- February
Nothing to do. Water pots in a dry spell.
- March
Flowering starts. Plant. Light feed.
- April
Plant. Mulch 5 cm with leaf mould or pine bark. Fleece the red growth on frost nights. Layer a low branch.
- May
Prune after flowering: remove dead flower sprays and frosted shoots, shorten stragglers. Renovate overgrown plants.
- June
Watch the leaf undersides for lace bug. Water in dry spells.
- July
Water with rainwater. Semi-ripe cuttings.
- August
Keep moist: next spring's flower buds form now. Nematodes on pots.
- September
Plant from now.
- October
Plant. Mulch the roots of plants in exposed spots.
- November
Nothing to do. Raise pots on feet.
- December
Nothing to do.
Feeding pieris
A light feeder: one half-rate feed in March and a spring mulch is the whole plan. Feeding into summer pushes soft late growth that frost and lace bug both go for. Never lime.
Low, ericaceous feed only.
Feeding plan
March, beds
Fruit & Vegetable Fertiliser 4-5-6
Half the label rate: 35 to 55 g/m² over the root area, watered in; about 30 to 45 g for a plant 1 m across (0.8 m²). This is not an ericaceous feed and does not acidify.
April
Leaf mould or composted pine bark
A 5 cm mulch, laid on the surface. In good acid soil this alone is enough for an established plant.
March, pots
Fruit & Vegetable Fertiliser 4-5-6
1 to 2 g per litre of compost on the surface, half the label top-dress rate: 30 to 60 g for a 40 cm pot (about 30 litres). Repeat at the lower figure in early June only if growth is pale and weak; nothing after June.
Autumn or early spring, only if a test shows pH above 6
To lower the pH by one unit: 55 g/m² on sand, 110 g/m² on loam in two doses six months apart, 175 g/m² on clay in three doses; never more than 80 g/m² in one go.
Dr Forest has no ericaceous feed. The plan uses the Fruit & Vegetable Fertiliser 4-5-6 at half the label rate as the nearest fit; it is not an ericaceous feed and does not acidify. Mycorrhizal Fungi Powder is not recommended for ericaceous plants.
Signs to watch
Yellow new leaves with green veins
Lime-induced chlorosis from alkaline soil or hard water
Rainwater, sulphur chips, ericaceous feed with chelated iron
Older leaves yellow between the veins in Aug
Magnesium short
Epsom salts foliar spray at 20 g per litre
Brown crisp leaf tips in a pot
Salt build-up or drought in Jul to Aug
Flush with rainwater, water daily in heat, feed only Mar to Jun
Pests, diseases and problems
Upper leaf surface bleached and finely mottled pale yellow; brown sticky spots and small lacy-winged insects underneath
Pieris lace bug, a sap-feeder active from late spring to autumn
Prune out the worst shoots after flowering and bin them. Spray the leaf undersides with a plant soap in late May and June, when the wingless young hatch. A plant in shade with moist roots suffers less than one in hot sun.
Red new shoots blacken and hang limp after a cold night in April or May
Late frost on soft growth
Fleece on forecast frost nights. Cut blackened growth back to a healthy bud in May; the plant makes a second flush.
Brown, crisp leaf margins and tips after winter
Cold, drying wind on an evergreen whose roots are in cold or frozen soil
Move or screen the plant, mulch the roots in autumn and keep pots watered in dry winter spells.
Notched leaf edges; a pot plant wilts in moist compost
Vine weevil
Nematodes watered into the pot in late August or September and again in April.
Foliage dulls and wilts, branches die back one by one in heavy or wet soil
Phytophthora root rot
No cure. Remove the plant and its soil, improve drainage, or replant in a raised bed or pot.
Pruning
Pruning and care
Flowers on last year's wood from buds formed in Aug to Sep, so prune straight after flowering in May, removing the dead flower racemes and shortening any straggly shoots by a third. Cut out frost-blackened red growth in May once new buds show. Overgrown plants renovate well to 30 to 45 cm in May over two years. Drape fleece over the red flush in a late Apr frost; a 5 cm pine-bark or leaf-mould mulch eac
Good to knowBright red young shoots ('Forest Flame'); shelter the new growth from late frost.
Growing pieris in pots
Pieris is a good pot shrub, and a pot lets you move the plant under cover when frost threatens the new growth. Dwarf and medium cultivars suit a 40 to 50 cm pot of ericaceous compost; 'Forest Flame' outgrows one in a few years. Stand it in part shade out of the wind, water with rainwater and do not let it dry out in July and August. Brown leaf tips in a pot usually mean drought or a build-up of feed salts, so flush with rainwater and feed less. Repot or top-dress every second March.
Pieris: common questions
Why are my pieris leaves turning pale and mottled?
Pieris lace bug is the usual cause: the top of the leaf looks bleached and speckled, and the underside carries brown sticky spots. Leaves that are yellow between green veins on the newest growth point instead to alkaline soil or hard water locking up iron.
Why has the new growth on my pieris gone black?
A late frost has killed the soft red shoots. It looks alarming but the plant recovers: cut the blackened growth back to healthy buds in May and it will flush again. Next year, cover it with fleece on cold April nights.
When do you prune pieris?
In May, straight after flowering. Take off the dead flower sprays, shorten any straggly shoots by a third and remove frosted tips. An overgrown plant can be cut back hard to 30 to 45 cm, best done in stages over two years.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.