Lombardy poplar

Sun

Full sun.

Water

Moderate to high; prefers consistently moist ground. Water deeply during establishment and prolonged dry spells.

Soil

Deep, moist but well-drained soil; tolerates clay and a broad pH range. Performs poorly in shallow, drought-prone ground.

Height

40-60 ft (12-18 m), sometimes taller

Spread

10-15 ft (3-4.5 m); roots and suckers extend much farther

Flowers

Red male catkins in early spring before the leaves; usually inconspicuous from a distance.

Foliage

Glossy green, triangular to diamond-shaped leaves on upright branches; turns yellow in autumn.

Growth

Fast, often 3-6 ft (0.9-1.8 m) a year when young in suitable conditions.

Care needed

High

• Cold hardy
• Heat tolerant
• Wildlife

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

Difficulty

Hard

Toughness

Needs looking after

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

1. Planting day

   7 ft (2 m)

2. After 1 year

   10 ft (3 m)

3. After 2 years

   13 ft (4 m)

4. After 3 years

   16 ft (5 m)

5. After 5 years

   23 ft (7 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

Mildly toxic: may upset a stomach

Native to

the UK

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Fast

• Plant well away from buildings, paving, drains and underground services; the narrow crown does not mean a small root system.
• Water deeply through the first two growing seasons, keeping the root area moist without leaving it permanently waterlogged.
• Apply 2-3 in (5-8 cm) of organic mulch over the root area, keeping it clear of the trunk.
• Avoid routine feeding; use a soil test before adding fertiliser.
• Remove root suckers promptly and inspect regularly for dead branches, cracks and cankers.
• Stake only if the root ball is unstable, and remove supports once the tree is firmly rooted.

Pruning. Prune in late winter while dormant, retaining one main leader and removing dead, damaged or crossing branches with small, clean cuts. Do not top the tree; use a qualified arborist for large limbs or work at height.

Late winter

Inspect the crown and trunk, and carry out necessary structural pruning before growth begins.

Spring

Plant while dormant or just before bud break where the soil is workable; water thoroughly.

Late spring

Renew mulch and remove emerging root suckers.

Summer

Water young trees during dry weather and check for leaf rust, cankers and branch dieback.

Autumn

Clear heavily diseased fallen leaves and check that stakes or ties are not rubbing the bark.

Late autumn

Plant dormant trees in mild regions; avoid planting into frozen or saturated soil.

• Plant in a formal avenue on a large property to create a strong perspective.
• Use a widely spaced row as a tall seasonal screen where roots and suckers can be managed.
• Place at the edge of open lawns or fields as a narrow vertical contrast to broad-canopied trees.
• Use in large Italian-style or estate gardens to frame distant views without forming a broad canopy.

Garden styles it suits: Formal, Italian / Tuscan, Grand estate, Architectural minimal, Traditional and Tuscan villa.

Plant it with: Yarrow, Catmint, Russian sage, Switchgrass and Feather reed grass.

Wildlife: Leaves support various moth caterpillars and other insects, and mature trees provide bird perches and nesting cover. The usual male clone produces pollen but no seed or cottony seed fluff.

• Canker and branch dieback: remove affected branches where practical, avoid drought stress and bark wounds, and have extensive trunk damage assessed by an arborist; replacement is often necessary.
• Leaf rust and leaf spots: collect badly affected fallen leaves and avoid wetting foliage; severe repeated defoliation can weaken the tree.
• Aphids and honeydew: tolerate light infestations and encourage natural predators; wash accessible colonies from young trees with water.
• Root suckers and root conflicts: remove suckers repeatedly and keep trees away from drains and paving; seek professional advice before cutting major roots.

Not generally known to be toxic to cats, dogs, horses or people through ordinary garden contact. Bark, buds and leaves contain salicylate compounds, so do not use them as animal feed or home remedies; substantial ingestion warrants medical or veterinary advice.

Where it spreads. Can spread aggressively by root suckers where planted in the United States, Canada, the United Kingdom and temperate Australia, particularly in moist ground. Suckers may extend beyond the crown and persist after felling; the usual male clone does not spread by seed.

• Black poplar (Populus nigra)

  The ordinary species usually develops a broad, spreading crown rather than the tightly columnar outline of 'Italica'.

• Swedish columnar aspen (Populus tremula 'Erecta')

  Also narrow and upright, but its leaves are rounder, with coarse, rounded teeth, rather than the more triangular leaves of Lombardy poplar.

• Pyramidal European hornbeam (Carpinus betulus 'Fastigiata')

  Has strongly ribbed, oval leaves with sharply toothed edges and a crown that broadens considerably with age.

Populus is the Latin name for poplar, nigra means black, and 'Italica' and Lombardy refer to the cultivar's Italian origin.

Propagation. Take hardwood cuttings from healthy dormant shoots in winter, or separate rooted suckers while dormant. Vegetative propagation preserves the cultivar; avoid taking material from trees showing canker or dieback.

Accepted botanical name

Populus nigra

In the US and Canada

Introduced in Canada and the lower 48 states.

Native range

Albania, Algeria, Altay, Austria, Baltic States, Belgium, Bulgaria, Central European Rus, Corse, Czechoslovakia, East Aegean Is. and East European Russia.

Measured

Soil pH 5 to 8.5. Average height 2100 cm.

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