Tree · Magnoliaceae
Saucer Magnolia
Magnolia × soulangeana
Set clear of late frost, the saucer magnolia unfurls goblet-shaped pink blooms on bare wood before a single leaf shows.
Full sun
Every 5–10 days
USDA 4–9
20–30 ft · 6.1–9.1 m
Overview
The saucer magnolia opens some of the earliest and largest flowers of spring. Each bloom is a broad, goblet-shaped cup of thick petals in pink, purple, and white, and on many forms the outer petals run deep rose-purple while the inside stays pale, so a half-open flower shows both tones at once. Because they crowd the bare wood before any leaf appears, the whole crown reads as a mass of upright, colored cups.
The tree itself is a hybrid of two Asian magnolias that grows as a multi-stemmed tree or large shrub, several trunks rising and branching into a broad, rounded head. At a moderate pace it reaches 20 to 30 feet (6.1 to 9.1 m) tall, the crown often as wide as the tree is high, its outer twigs studded in late winter with plump, felted flower buds. That rounded, low-branched frame is what gives it such presence out of leaf.
The catch is written into those early flowers. The petals are thick but tender, and they open so soon that a single frosty night can brown and soften them where they stand. Set beyond the reach of late frost, though, the plant is an easy, long-lived tree that asks for little once its roots take hold.
Care
The short version: full sun to light shade, moist and acidic well-drained soil, steady water, and a sheltered spot that keeps late frost off the thick early petals. Prune lightly, and only right after the flowers fade.
Light
The tree flowers hardest in full sun, though it holds up in partial shade and partial sun. The more direct light reaches the crown, the thicker the set of cupped blooms and the fuller the head of branches.
Water
Keep the soil evenly moist year-round, since this tree turns fussy in both drought and standing water. Soak it deeply while it establishes and through dry spells, roughly every 5 to 10 days as the weather and soil dictate.
Soil
It roots best in moist, acidic, organically rich loam that still drains freely. Hold the pH between 5.0 and 6.5 and fold in plenty of dark organic matter, since alkaline or packed ground stunts it.
Temperature
The bare wood is hardy across a wide sweep, from winter cold near -29°F (-34°C) to summer heat around 100°F (38°C). The frailty is not the tree but its early petals, thick yet frost-tender, which a cold night can brown.
Humidity
Plain outdoor air suits it, so there is no figure to chase. Steady moisture at the roots counts far more than the humidity brushing the branches.
Feeding
Feed in early spring with a balanced slow-release fertilizer or a layer of dark compost, once a season. Skip heavy feeding late in the year, since soft new shoots will not firm up before the cold.
Pruning
Keep pruning light and reach for the tools only right after flowering, taking out dead, damaged, or crossing branches. The flower buds ride on old wood, so a hard cut strips away next spring's cupped blooms.
Repotting
This is a landscape tree, rarely held in a pot, so repotting seldom comes up. If one is potted and roots coil at the surface, growth stalls, or water slides straight through, shift it up a size.
Size & spacing
Picture a mature tree of 20 to 30 feet (6 to 9 m) tall under a broad, rounded crown spreading 15 to 25 feet (4.5 to 7.5 m) across. Give it that full width of open ground away from walls and other trees so the low, spreading frame can fill out.
When to plant
The saucer magnolia keeps an early-spring rhythm. The fat buds split and the cupped flowers open from late March to mid-April, ahead of the leaves, which is exactly why a sheltered site protects them. Plant it in spring or fall while it is bare and dormant, ahead of summer heat, so the roots settle before growth begins.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall while dormant or before heat of summer
- Harvest: Early spring (late March to mid-April), before the leaves emerge
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
A strong saucer magnolia stays mostly trouble-free, and what marks it is usually shallow rather than serious. The soft petals show trouble first, then the twigs and the leaf blades. Match the look below to tell whether the tree needs a hand or simply time.
Shiny white waxy mounds studding the twigs, filmed with black
The shiny, soft, white-waxy mounds clustered along the twigs are magnolia scale, one of the largest scale insects, each swollen lump packed tight against the bark as it feeds. They weep a sticky, glistening honeydew that films the branches in black sooty mold and draws humming wasps and ants. Cut out the worst-crusted twigs, coat the overwintering nymphs with dormant oil in late fall or early spring, and hit the pale crawlers in late summer as they creep along the stems.
Fix:
- Prune out and destroy heavily infested twigs
- Treat overwintering nymphs with dormant horticultural oil in late fall or early spring
- Time crawler-stage treatments to late summer when young scales are active
Petals turn brown and soft, then slump on the branch
When the open petals go slack, brown, and mushy soon after they unfurl, the cause is nearly always late-spring frost on the early, pre-leaf flowers rather than a disease. A warm south-facing wall pushes the buds to swell and split open even sooner, straight into the cold. The frosted petals will not firm up again, yet the bare wood beneath them is sound and the green leaves still push out on time, so leave the live wood and pick off the browned flowers only to clean up the look.
Fix:
- Accept that frosted blooms cannot be revived; remove spent flowers for appearance only
- Do not prune live wood in response, as the tree itself is unharmed and will leaf out normally
Dark leaf spots or sunken, discolored patches on the wood
Discrete dark spots and blotches scattered over the leaf blades are usually fungal or bacterial leaf spot, while a sunken, discolored patch pressed into the wood marks a canker that takes hold on a tree already under strain. On a strong magnolia both stay shallow and minor. Gather the fallen, spotted leaves and bin them, carve out the cankered wood with clean tools, and thin the crowded stems so air slides through the canopy.
Fix:
- Rake and dispose of fallen infected leaves
- Prune out cankered or dead wood with sanitized tools
- Improve air circulation and avoid overhead wetting of foliage
Toxicity
For a home with pets or children, the saucer magnolia is safe to plant and to touch. The ASPCA lists magnolia as non-toxic to cats, dogs, and horses, and it poses no poisoning risk to other animals or people. The worst a big mouthful of leaves might bring is a brief, mild stomach upset, as with most plants.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe for cats. A cat mouthing a smooth leaf or a fallen petal takes in no poison, and only a large wad of any plant might turn it briefly queasy.
Dogs None
No toxic compound sits in the wood or foliage, so a dog gnawing a low branch or lipping a dropped bloom comes to no harm. The most a heavy binge brings is passing stomach upset.
Horses None
The ASPCA lists magnolia as safe for horses, so a horse cropping the leaves faces no poisoning risk.
Rabbits Safe
Rabbits can nibble the leaves without harm. As with any fresh green, let them build up to it slowly so the gut adjusts.
Livestock Safe
Cattle, goats, and sheep can browse a saucer magnolia with nothing to fear, since no toxin sits in the leaves, bark, or flowers.
Birds Safe
Birds pecking at the fat buds, open flowers, or seeds come to no harm from the tree.
People Safe
Nothing on the tree is poisonous to people. The petals even reach some kitchens, so children need not be kept away.
No special handling precautions needed; as with any plant, ingestion of large amounts of foliage may cause mild, transient stomach upset.
Varieties
Most saucer magnolias sold are named cultivars, sorted by the color, size, and shape of the flower. A few turn up again and again, each with its own cast of petal color, and these are the ones worth knowing.
Alexandrina
A vigorous, widely grown form whose large flowers glow deep rose-purple on the outer petals and clean white within.
Lennei
Its heavy, goblet-shaped blooms are dark rose-purple outside and white inside, and they open a little later, slipping past some of the frost.
Brozzonii
One of the largest-flowered forms, opening huge white blooms brushed with light purple toward the base of each petal.
Rustica Rubra
A strong grower carrying deep, cup-shaped flowers in rosy-red to reddish-purple.
How to propagate
Because the saucer magnolia is a hybrid, seed will not copy the parent, so every dependable method clones the plant instead. The techniques run from a simple bend-and-pin to skilled bench work.
GraftingDemanding
Late winter to early spring for bench grafting onto seedling rootstock · 1 to 2 growing seasons
A named hybrid comes true only when cloned, so seed will not reproduce the cultivar reliably. Growers bench graft a scion onto seedling rootstock in late winter to early spring, joining the two into one stem. The young tree then takes 1 to 2 growing seasons to knit together and settle in.
LayeringModerate
Spring, on low flexible branches · 1 to 2 years to root before separating
For a home gardener this is the most forgiving route. In spring, bend a low, supple branch down and pin it into the soil, or wrap an air-layer higher up, and the new roots carry the parent cultivar exactly. Allow 1 to 2 years for a firm root system before cutting it free.
Stem cuttingsDemanding
Early summer using softwood to semi-hardwood cuttings · Several weeks to root, then a season to establish
Cut soft, green softwood to firmer semi-hardwood pieces in early summer, though rooting stays slow and hit-or-miss. A dip of rooting hormone and the damp air of a mist bench tip the odds up. Roots form over several weeks, and a full season follows before the young plant establishes.
Myths
Saucer magnolia is poisonous to cats and dogs and should be kept away from pets.
The ASPCA lists magnolia as non-toxic to dogs, cats, and horses, so it is no poison hazard at all. A pet that nibbles a leaf or petal is safe, and the tree needs no fencing or special precautions.
Frosted, browned blooms mean the magnolia tree is dying and needs heavy pruning.
A late frost scorches only the open early petals, not the tree beneath. The wood is unharmed and leafs out on schedule, so a hard cutback gains nothing and costs next year's blooms, since magnolias flower on old wood.