Caring for Sweet Gum

Sweet gum is low-maintenance once established. Water young trees regularly during their first two growing seasons, especially in dry spells; aim for a deep soak every 7–10 days rather than frequent shallow watering, which encourages surface rooting. Mature trees are moderately drought-tolerant and usually manage on rainfall alone, though prolonged summer drought may cause premature leaf drop. Feed in March or April with a balanced slow-release fertiliser (such as blood, fish, and bone) or a general tree and shrub feed. Scatter a handful around the root zone—roughly the area beneath the canopy—and water in if the soil is dry. Avoid high-nitrogen feeds, which promote soft growth at the expense of autumn colour. Mulch annually in spring with a 5 cm layer of organic matter to suppress weeds, retain moisture, and improve soil structure as it breaks down. Sweet gum is fully hardy across zones 5a–9b and needs no winter protection. The spiky seed balls (gumballs) can be a nuisance on lawns and paths; rake them up in autumn and winter, or choose a cultivar bred to produce fewer fruits if this is a concern. Pests and diseases are uncommon. Occasionally aphids may colonise new growth in spring, causing sticky honeydew; a strong jet of water usually dislodges them, or leave them for natural predators. Leaf spot fungi can appear in wet summers but rarely warrant treatment. Chlorosis (yellowing leaves with green veins) indicates iron deficiency on alkaline soils; apply a chelated iron feed if this occurs.