Oyama magnolia

Oyama magnolia: how do you recognise it?

Habit

Broad, loose deciduous shrub or small tree of about 4 m high and wide, with an open crown.

Leaves

Oval to elliptic, 6–16 cm, dark green above and blue-green beneath; yellow in autumn.

Flowers

Nodding, cup-shaped white flowers of 7–10 cm with a red centre of stamens, from May to July.

Scent

Sweet, fresh and strong, especially on calm, warm days.

Fruit

Pink-red fruit cones with bright red seeds, in autumn.

Roots

Fleshy, sparsely branched and shallow; dislikes disturbance.

Flowering: May–July · Plants: March–May · Pruning: August

Why grow it?

• Delicately scented, nodding white flowers with a red centre, from May to July.
• Flowers late, after the leaves have emerged: the buds are not at risk from late spring frosts.
• Stays a manageable size and suits small and medium gardens and a half-shaded border.
• Attractive pink-red fruit cones with red seeds in autumn.
• Bees and other insects visit the flowers; beetles have pollinated magnolias since ancient times.

Oyama magnolia: where does it grow best?

• Half shade, ideally with shade during the hottest hours; in full sun it needs plenty of moisture.
• Humus-rich, moisture-retentive, acid to neutral soil: sand, loam or peaty soil; not on chalky soil.
• Evenly moist but not waterlogged; it dislikes drying out for long.
• Sheltered from strong wind and cold east winds. Allow 3–4 m of free space.

Light

Partial shade

Soil type

Sand, loam or peat

Acidity

Acid or neutral

Moisture

Normal

Size

4 m tall, 4 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Rhododendron: Likes the same acid soil and half shade.
• Hosta: Broad leaves at the foot in shade.
• Ferns: Fresh, green underplanting.
• Japanese maple: Fine foliage and lovely autumn colour next to the magnolia.
• Anemone: A low flower that suits under the shrub.

Oyama magnolia: when and how to plant it?

Plant in March–May.

1. Plant in March–May, preferably in spring, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the rootball and no deeper; the fleshy roots hate deep planting.
3. Gently remove the plant from the pot without pulling on the roots and set it slightly higher than in the pot.
4. Backfill with the garden soil mixed with leaf mould or ericaceous compost; firm lightly.
5. Water in generously straight away, even if it rains, and spread a layer of leaf mould or bark around the base.

Care

Water

In the first year water generously once a week in dry weather, preferably with rainwater. Also water later in long droughts.

Feeding

A thin layer of leaf mould in spring or a fertiliser for acid-loving plants. Not too much, and not on chalky soil.

Mulching

A layer of leaf mould or bark in spring keeps the roots cool and moist; do not hoe around the base.

Keeping soil acid

On slightly chalky soil: use ericaceous compost, rainwater and leaf mould, and avoid lime-containing fertilisers.

Position

Avoid moving it: the root system is sensitive and it should stay in the same place for years.

Tip: Give it a sheltered spot in half shade with acid, moist soil and a thick layer of leaf mould, then leave it alone: it dislikes both moving and pruning.

Oyama magnolia: when to prune it?

Pruning months: August.

When: Hardly at all; if necessary in late summer, in August, when the plant is in leaf.

How:

• Remove dead, damaged and crossing branches back to healthy wood.
• Shorten unwanted branches back to a side branch, leaving no stubs.
• Use clean, sharp secateurs or a saw and keep the wounds small.
• Keep the natural, open shape: never clip it into a rigid ball.

Caution: Do not prune magnolias in winter or early spring: they bleed then and wounds heal slowly.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Layering

In spring bend a low branch down to the ground, nick it lightly and pin it down; it is rooted after one to two years and can be separated.

Seed

Sow fresh seed from the fruit cones in autumn or keep it cold and moist for a few months (stratification). Seedlings grow slowly and only flower after several years.

Softwood cuttings

Summer cuttings root with difficulty; nurseries usually buy in grafts or propagate by layers.

Oyama magnolia: how does it get through the winter?

Hardy to −25 °C.

• Hardy to about −25 °C: in Flanders no protection is needed for a mature plant.
• Young plants get a thick layer of leaf mould or bark around the base for the first winters.
• In a pot (only as a stopgap): a large pot with ericaceous compost, against a sheltered wall and the pot wrapped in hessian.

Diseases and pests

• Chlorosis (yellow leaves): Yellow leaves with green veins on chalky soil. Use ericaceous compost, rainwater and leaf mould; an iron fertiliser if necessary.
• Leaf scorch: Brown leaf margins caused by dry wind or drought. Plant in shelter and keep the soil evenly moist.
• Scale insects: Sticky leaves and small brown shields on the stems. Brush them off; ladybirds help.
• No flowers: Young plants sometimes only flower after several years; too much nitrogen or too much shade gives few flowers.

Through the year

• March: Plant. Apply acid leaf mould.
• April: Plant. Apply mulch.
• May: First flowers appear. Water in dry weather.
• June: Full bloom and scent. Water in dry weather.
• July: Last flowers. Water in dry weather.
• August: Prune lightly if needed. Water in dry weather.
• September: Pink-red fruit cones. Collect seed for sowing.
• October: Autumn colour. Apply mulch before winter.
• November: Protect young plants with leaf mould.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The species is named after Philipp Franz von Siebold, the German physician and naturalist who introduced many Japanese plants to Europe.
• Magnolia sieboldii is the national flower of North Korea.
• Magnolias are very old flowering plants: their flowers are adapted to pollination by beetles, from before bees existed.