Paulownia fortunei


Michael's Opinion

P. fortunei’s blooms are undeniably attractive; to me, however, its seemingly oversized foliage has equal aesthetic appeal. With that being said, I cannot foresee myself ever planting one – unless I move to China, which is very unlikely – for the following reasons. Compared to the hardier Paulownia tomentosa, fortunei is not a popular specimen in Europe or North America. This is justified, as examples of longevity and successful natural reproduction are rare beyond the tender tree’s native climate. Consequently, however, fortunei’s potential as an invasive species is comparatively reduced; but of course, gardeners in temperate climates should still plant this tree with caution. Since tomentosa became a weed, the whole Paulownia genus has been under scrutiny.

Botanical Information

FamilyScrophulariaceae
GenusPaulownia
Speciesfortunei
CategoryWoody
TypeTree (deciduous)
OriginNative to China and parts of Taiwan.
Ethnobotanical Uses
Disclaimer
The wood is arguably fortunei’s most valuable commercial asset. It is strong yet lightweight, attractive, and dries quickly, making it ideal for artisans and craftspeople. It is used to build musical instruments, furniture, and trinkets. The leaves of various Paulownia species, including fortunei, are high in nitrogen 11, making for an effective organic fertilizer. Paulownia have also been used medicinally in China.

Details

USDA Hardiness Zone6 - 10
USDA Hardiness Ref.
Canadian Hardiness Zone7b
Canada Hardiness Ref.
RHS Hardiness ZoneH5
RHS Hardiness Ref.
Temperature (°C)(-15)
Temperature (°F)5
Height4 - 20 m
Spread4 - 20 m
GrowthMedium
Flowering PeriodMarch, April

Description and Growing Information

General DescriptionA deciduous tree originally from East Asia, where it has considerable cultural and ethnobotanical significance. Flower clusters appear in the spring along with leaves, which eventually grow to be very large. Trunk is notably straight and often tall, culminating in a sparse, conical or pyramidal crown.
ID CharacteristicPaulownia are most recognizable for their inflorescences. P. fortunei’s lower branches, which appear long and delicate, tend to develop a subtle yet distinct downward swoop. The racemes these culminate in – which are retained after the leaves have fallen – point upwards. This contrast gives the tree a distinct, dynamic silhouette. P. fortunei can be distinguished from other species of Paulownia by the slight pyramidal habit of its crown.
ShapeThis tree is known for its very straight trunk and upright habit. The crown is somewhat conical, with a slight pyramidal habit that can be accentuated with pruning. Large, mature specimens may develop a rounder, spreading shape. Lateral boughs and branches which are not removed may become long and heavy over time, causing them to adopt an almost pendulous, swooping appearance.
LandscapeP. fortunei’s attractive flowers give it considerable springtime seasonal appeal. As such, it is most often planted as an ornamental specimen. Suitable for areas that are protected yet not shaded, for example: a well-maintained public park, garden, or private backyard. If the climate is appropriate for growth and longevity, P. fortunei can become a shade tree as well.
PropagationP. fortunei can produce millions of seeds. However, these are unlikely to germinate in contaminated soil; when they do, they are slower growing and more tender than rooted cuttings. It is therefore recommended to use the hardy roots to propagate this tree. Acquire root cuttings from healthy trees that are at least 1-2 years old, between late autumn and early spring (while the tree is dormant). New trees also frequently sprout from the stumps of previous, fallen or cut trees, as their roots are generally hardy. It is also possible to propagate P. fortunei from stem cuttings.
CultivationFull sun. P. fortunei is not suitable for windy/exposed locations, or locations that regularly experience harsh winters. Thrives in deep, fertile soil; yet has been known to tolerate extremely poor soils, according to accounts of its use in afforestation efforts involving various Paulownia species. Ideal pH between 6.0 and 8.0. Can be grown in slightly acidic soils as well.
PestsP. fortunei has few pest problems outside its native region. In it’s natural habitat, however, it has been affected by witch’s broom, borers, and scale.
Notable SpecimensVilla Taranto, Pallanza, Italy. Peasmarsh Place, East Sussex, UK.
HabitatNative to China and parts of Taiwan. Grows in subtropical forests, often on or around mountain bases.
Bark/Stem DescriptionP. fortunei’s grey-brown bark is initially very smooth, becoming increasingly fissured as it ages. Young branches are covered in conspicuous, small white lenticels. The fissures in mature trees are narrowly spaced, and typically appear shallow relative to the girth of the tree.
Flower/Leaf Bud DescriptionFlower buds are encased in an obconical, 2 lobed, medium brown calyx. Leaf buds are pale green, often with a glabrous, brown tint. They have an ovate shape with accuminate tips, and are attached to brown petioles which lengthen and turn green as the leaf matures.
Leaf DescriptionSimple, with a narrow ovate-cordate shape. Opposite arrangement. Leaves can grow to be quite large – over to 30 cm in both directions – and are longer than they are wide. The leaf tips are acuminate. Mature leaves have entire margins; new leaf margins appear serrated. Stellate pubescence can be felt across the undersides of the leaves, while their surfaces are glabrous in texture. Its yellow and brown autumn colour is unremarkable.
Flower DescriptionP. fortunei’s flowers appear in the spring, on brown racemes which point upwards. Mature corollas, attached to brown peduncles, and have a tubular shape. Flower colour ranges from light mauve or violet to a purple tinted off-white. Slightly deeper striped purple markings often present towards the centre of the blooms. The corollas are two lipped with five lobes: two lobes on the top lip, and three on the bottom.
Colour DescriptionShowy inflorescences are typically a very light purple or off-white, with distinct purple markings and undertones; the paler colouring has been described as ‘silvery’. Some cultivars have been bred to exhibit deeper violet and mauve hues. Through spring and summer, leaves have medium green surfaces with paler green undersides. In autumn, they turn yellow and brown before falling. Bark ranges from warm brown to grey-brown.
Texture DescriptionMedium.

Photographs