Arborvitae in April: monthly care

Arborvitae thrives in full sun or partial shade, though plants grown in full sun develop denser, more compact foliage. It tolerates a wide range of soil types—loam, clay, and sandy soils all suit it—provided drainage is reasonable. Avoid waterlogged ground, which can lead to root rot. Plant container-grown arborvitae in March, April, May, September, or October. Autumn planting is often ideal because cooler, wetter weather helps roots establish without the stress of summer heat. Dig a hole roughly twice the width of the root ball but no deeper; the top of the root ball should sit level with the surrounding soil. Break up compacted soil at the base and sides of the hole to encourage roots to spread. If you're planting a hedge, space plants 40 cm apart for a dense screen. For specimen trees, allow at least 80–100 cm between plants to accommodate their mature spread. After positioning the plant, backfill with the excavated soil, firming gently to eliminate air pockets. Water thoroughly immediately after planting to settle the soil around the roots. Apply a 5–7 cm layer of organic mulch—bark chips or well-rotted compost—around the base, keeping it a few centimetres clear of the trunk to prevent rot. Mulch conserves moisture and suppresses weeds while roots establish. Newly planted arborvitae benefit from regular watering during their first growing season, especially in dry spells. Check soil moisture weekly and water deeply if the top few centimetres feel dry. Staking is rarely necessary unless planting in an exposed, windy site.

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.