Sweet Gum · Liquidambar styraciflua

Liquidambar styraciflua (Liquidámbar) is a medium to large deciduous tree native to the warm-temperate eastern United States and the cloud forests of Mexico and Central America. In Iberian cultivation it reaches 15 to 25 m, pyramidal in youth and broadening to a domed crown on a straight bole. The glossy, five to seven-lobed star-shaped leaves turn through yellow, orange, scarlet and deep purple over a long autumn window. It serves where the autumn programme of a Platanus or an Acer is wanted on acidic soils those genera handle less well.

Hardiness is reliable to around -25 °C, which puts the species well inside the envelope of every Spanish climate zone, including the colder meseta interiors of Castilla and Aragón. Performance differs sharply across the peninsula. On the humid Atlantic strip (cornisa cantábrica) and in northern inland sites with cool wet summers, the tree thrives and colours strongly. Across the Mediterranean coastal belt the autumn show fades unless soils stay sufficiently acid and moist; in the semi-arid southeast (Almería, Murcia), performance is marginal and not recommended.

Soil preference is moist, well-drained loam on the acidic side. Calcareous and alkaline substrates, common across the meseta and much of the Mediterranean basin, induce iron chlorosis and dull the autumn colour; specification on those sites requires soil correction or another species. Water demand is moderate; established trees on deep acid loam tolerate short drought episodes through a deep root system, but recurrent summer drought without irrigation produces leaf scorch and early defoliation. The species sits outside the known Xylella fastidiosa host range, which removes one constraint inside demarcated zones.

Crown shape and the persistent woody seed capsules, spiny gumballs 25 to 40 mm across, are the two specification facts that decide most projects. The fruit creates a real litter load on paving, lawns and play surfaces from December into spring; for high-traffic urban pits or patios the fruitless selection 'Rotundiloba' resolves the issue. Branches can be brittle in storms, so siting away from primary footfall on exposed sites is sound practice.