Caring for Arborvitae

Arborvitae has moderate water needs. During the growing season, water established plants during prolonged dry spells—roughly once a week if there's no significant rain. Newly planted specimens need more frequent watering in their first year. In winter, evergreen foliage continues to lose moisture, so water occasionally during dry winters, especially if plants are in containers or sheltered spots that don't catch rain. Feed in March or April with a balanced slow-release fertiliser or a general-purpose granular feed (such as Growmore) scattered around the base at the manufacturer's recommended rate. Alternatively, apply a mulch of well-rotted compost or manure in early spring; this feeds the soil and helps retain moisture. Avoid feeding after late spring, as soft new growth produced in summer is more vulnerable to frost damage. Arborvitae is exceptionally hardy (zone 3a–8b) and requires no special winter protection in temperate Europe. Evergreen foliage may bronze slightly in cold weather, particularly in exposed sites, but this is normal and green colour returns in spring. Heavy snow can splay branches outwards; gently brush off accumulations to prevent damage. Pests are rarely serious. Aphids occasionally cluster on new growth in spring; a strong jet of water usually dislodges them, or use an insecticidal soap if necessary. Conifer aphids can cause yellowing foliage. Fungal issues such as leaf blight (Didymascella thujina) may appear in damp conditions, causing browning foliage; improve air circulation and remove affected material. Root rot can occur in waterlogged soil, so ensure good drainage from the outset. Maintenance is low overall—mulch annually, water in dry spells, and keep hedges lightly trimmed.