How to grow Paulownia

Paulownia tomentosa, sometimes called the Foxglove tree, is grown in tropical style gardens for it’s enormous leaves that can get to 30cm long. It’s common name of Foxglove tree comes from the flowers which bare a slight resemblance to the flowers of the perennial foxglove.

Although the plant is hardy the pale purple flowers do not always form in the UK because the flower buds do not over winter very well in temperatures seen in a Uk winter. Should the buds be kept frost free then the flowers will form in April to May.

To get the big leaves Paulownia tomentosa must be cut down quite hard. If left to its own devices the plant can grow into a 12m whopper but not grow particularly big leaves.

How to propagate

Paulownia tomentosa can be grown from cuttings, root cuttings or from seed. Trees grown from cuttings is the quickest way to get a decent sized plant. Just cut a 30cm young shoot with a diagonal cut and push it in to some potting compost. Water well and keep in a frost free place at a coolish temperature over winter.

How to Grow Paulownia (Empress Tree / Princess Tree)

Paulownia is a fast-growing, deciduous tree known for its large heart-shaped leaves, striking clusters of lilac-blue flowers, and rapid growth. It’s an excellent choice for ornamental gardens, screens, and timber production. Some species are even grown for biofuel or carbon sequestration due to their fast growth.

Botanical Profile

• Family: Paulowniaceae
• Genus: Paulownia
• Common Names: Empress Tree, Princess Tree, Kiri Tree
• Plant Type: Deciduous tree, fast-growing, hardy
• Height: 10–20 m (depending on species and site)
• Foliage: Large, heart-shaped leaves up to 30 cm long
• Flowers: Panicles of lilac-blue, trumpet-shaped flowers, appearing in spring before leaves emerge
• Origin: Eastern Asia, mainly China
• Growth Rate: Very fast — can grow 2–3 m per year in ideal conditions

Paulownia is prized for ornamental beauty, rapid shade, and timber potential.

Best Planting Conditions

Light

• Prefers full sun for optimum flowering and rapid growth
• Can tolerate light shade, but growth slows

Soil

• Fertile, well-drained soil
• Tolerates sandy, loamy, or slightly clay soils
• Avoid waterlogged soils, which can cause root rot
• Prefers neutral to slightly alkaline pH

Position

• Large gardens, parks, or timber plots
• Space for a spreading canopy, as leaves are large
• Shelter from strong winds is beneficial, especially for young trees

Planting Guide

• Planting time: Spring or autumn
• Spacing: At least 4–6 m from other trees or structures
• Planting method:
  1. Dig a hole twice the width of the root ball
  2. Backfill with topsoil enriched with compost
  3. Water well and mulch around the base to retain moisture

Tip: Stake young trees in exposed sites to prevent wind damage

Hardiness

• UK hardiness: H6–H7 (RHS) – hardy throughout the UK, tolerates temperatures down to about -15°C to -20°C
• USDA zones: 5–9
• Winter behaviour: Deciduous; loses leaves in winter, hardy once established

Watering & Feeding

• Watering: Keep soil moist during establishment, especially in first 2–3 years
• Feeding: Fertilise in spring with balanced slow-release fertiliser or well-rotted compost
• Mature trees are drought-tolerant but benefit from watering in dry spells

Maintenance

• Pruning:
  • Minimal pruning needed, mainly to remove dead or crossing branches
  • Can be pruned to shape a single-trunk specimen
• Pests/Diseases: Relatively pest-free; occasionally aphids or leaf-spot diseases
• Leaf litter: Large leaves drop in autumn — plan space for cleanup

Propagation

1. By seed:
   • Seeds germinate easily in spring
   • Produces trees slower to maturity than cuttings
2. By root or stem cuttings:
   • Root cuttings or softwood cuttings in spring
   • Produces faster-growing, flowering trees

Vegetative propagation is preferred for reliable flower colour and timber traits.

Companion Plants

• Plant as a specimen tree in large spaces or with low-growing shrubs and perennials beneath
• Works well near ornamental grasses, flowering borders, and tropical-style plantings

Common Problems

• Young tree damage: Strong winds can break soft wood
• Root rot: Poor drainage or waterlogged soil
• Self-seeding: Some species can spread aggressively if seeds are left unchecked

Flowering Period

• Typically late April to May in the UK
• Flowers appear before the leaves fully develop, creating a spectacular floral display

Quick Summary

• Type: Deciduous fast-growing tree
• Height: 10–20 m
• Light: Full sun
• Soil: Fertile, well-drained; tolerates neutral to slightly alkaline
• Planting: Spring or autumn; stake young trees
• Flowering: Spring (April–May)
• Care: Water during establishment, minimal pruning, mulching helps moisture retention
• Propagation: Seed or cuttings (vegetative for faster flowering)

With its fast growth, striking flowers, and large leaves, Paulownia is a versatile tree for ornamental, timber, and ecological planting schemes.