Foxglove tree

Sun

Full sun, sheltered from strong winds; flowering is best where summers are warm.

Water

Water regularly while establishing. Established trees tolerate some drought, but prolonged dryness reduces growth.

Soil

Deep, reasonably fertile, well-drained soil; tolerates a range of soil textures and pH levels but dislikes waterlogging.

Height

30-60 ft (9-18 m)

Spread

30-40 ft (9-12 m)

Flowers

Fragrant lavender-purple, foxglove-shaped flowers in upright clusters in spring, before the leaves; overwintering flower buds are vulnerable to frost.

Foliage

Large, soft, heart-shaped green leaves with hairy undersides; leaves on annually cut-back shoots can exceed 2 ft (0.6 m) across. Autumn colour is usually unremarkable.

Growth

Fast; vigorous young shoots can grow several feet in a season.

Care needed

Medium

• Pollinators
• Drought tolerant
• Heat tolerant
• Low allergen
• Fragrant

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2 m)

2. After 1 year

   9 ft (2.9 m)

3. After 2 years

   12 ft (3.8 m)

4. After 3 years

   15 ft (4.7 m)

5. After 5 years

   21 ft (6.4 m)

About 13 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Invasive in

the US

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Fast

• Check local invasive-plant guidance before planting; choose another tree where this species is invasive.
• Water deeply during dry spells for the first two growing seasons.
• Apply organic mulch over the root area, keeping it clear of the trunk.
• Avoid routine high-nitrogen feeding, which encourages soft growth vulnerable to frost and wind.
• Give the crown ample space and remove unwanted seedlings and root suckers promptly.

Pruning. For a tree, prune lightly in late winter or early spring to establish a strong leader and remove dead or poorly attached branches. For giant foliage, cut established plants back to a low framework in early spring, accepting that this removes the flower buds and prevents flowering that year.

Late winter

Inspect the framework and remove dead or damaged branches; retain healthy shoots if flowers are wanted.

Early spring

For foliage-only plants, cut established stems back to a low framework before vigorous growth starts.

Spring

Plant when the soil is workable and not waterlogged; water thoroughly and mulch.

Late spring

Check for frost-damaged shoots and remove dead tips once healthy growth is evident.

Summer

Water young trees during dry weather and pull seedlings while small.

Autumn

Remove reachable seed capsules before they split where seed escape is a concern; continue checking for suckers.

• A flowering specimen in a large lawn, with enough room for its broad crown.
• An annually cut-back foliage feature behind grasses and late-flowering perennials.
• A bold-leaved accent in tropical-style planting with cannas and hardy bananas.
• A seasonal canopy in a spacious courtyard sheltered from strong winds, away from paving and buildings.

Garden styles it suits: Architectural minimal, Modern tropical, Grand estate, Victorian, Chinese scholar garden and Green on green.

Plant it with: Hardy banana, Canna, Japanese forest grass, Japanese anemone, Hosta and Ornamental rhubarb.

Wildlife: Flowers provide nectar and pollen for visiting insects, including bees. Outside its native range, its value to wildlife does not outweigh the risk of invasion where it displaces native vegetation.

• Frost-damaged flower buds: choose a sheltered position outside frost pockets; the tree may survive cold winters without flowering reliably.
• Root rot in wet ground: plant in freely draining soil and avoid sites that remain saturated.
• Cankers and branch dieback: remove affected wood back to healthy growth in dry weather and avoid injuring the trunk.
• Wind damage to large leaves and young shoots: provide shelter and develop a sound branch framework while the tree is young.

Not known to be toxic to people, cats, dogs or horses. It is not a food plant; avoid eating its leaves, flowers or seeds.

Where it spreads. Invasive across substantial parts of the eastern United States, especially the Southeast and Mid-Atlantic, with spread also recorded farther north and into parts of the Midwest. Its windborne seeds colonise disturbed ground, rocky slopes and burned woodland, and damaged roots can sucker.

• Southern catalpa (Catalpa bignonioides)

  Also has large heart-shaped leaves, but bears white, marked flowers after the leaves emerge and long, narrow bean-like seed pods rather than paulownia's egg-shaped woody capsules.

• Northern catalpa (Catalpa speciosa)

  Has white flowers in late spring or early summer and long, slender seed pods; paulownia flowers are lavender-purple and its capsules are short and oval.

• Velvetleaf (Abutilon theophrasti)

  Young plants have similarly soft, heart-shaped leaves, but velvetleaf is an annual herb with alternate leaves and small yellow flowers, not a woody tree with opposite leaves.

Paulownia honours Anna Pavlovna, daughter of Tsar Paul I of Russia, while tomentosa refers to the plant's woolly hairs and foxglove tree describes its tubular flowers.

Propagation. Propagates readily from surface-sown seed in spring, which needs light to germinate, or from root cuttings taken during dormancy. Avoid propagating it where it is invasive; root disturbance can also trigger unwanted suckers.

Accepted botanical name

Paulownia tomentosa

Native range

China North-Central, China South-Central, China Southeast, Korea and Manchuria.

Measured

Soil pH 4.5 to 7.5. Average height 1525 cm.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.