Garden Care Guide

Eastern Arborvitae Care

Thuja occidentalis

Likes sunny or partially shaded areas and moist, well-drained soil. It is sensitive to hot and dry climates, so it needs regular summer irrigation in Izmir. Often used as a hedge and screening plant.

Hardy · -35 °C / -31 °F

Monthly care calendar

Timings are for a temperate Northern Hemisphere climate. In warmer areas tasks start earlier, in colder areas later; in the Southern Hemisphere shift them by six months.

January
  • Watering: Not required; winter rains are sufficient. Water only if an unusually long dry winter occurs.
  • Pruning: Avoid hard pruning. Only remove branches that could break under snow load.
  • Plant protection: Application of dormant oil can be planned for overwintering pests (spider mite eggs, scale insects).
  • General care: Cold winter winds can cause bronzing on the leaves; this is normal.
  • Pests & diseases: Check the trunk and branches.
February
  • Fertilizing: At the end of the month, before new growth starts, a slow-release, balanced fertilizer (e.g. NPK 10-10-10) can be applied. Do not overfeed.
  • Pruning: Remove branches damaged in winter. Wait for new shoots to emerge before the main pruning.
  • Plant protection: This is the last chance for dormant oil application.
  • General care: The plant is preparing to wake up. The bronze color formed over winter begins to turn green.
  • Pests & diseases: Make sure drainage is good against root rot.
March
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • Fertilizing: If fertilizing has not been done, it can be done at the beginning of the month.
  • Pruning: New shoots begin to become distinct; wait until the end of the month or May for pruning.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Suitable period for planting and transplanting. Flowering begins.
  • Pests & diseases: Check the branches and trunk for brown, fixed bumps (scale insects).
April
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • Pruning: After the new shoots have lengthened, the first shaping or hedge pruning can be done. Avoid pruning into old, leafless wood.
  • Plant protection: Watch out for bagworms (small bags on the tree) and scale insects.
  • General care: Suitable period for planting and transplanting. Flowering continues.
  • Pests & diseases: Natural leaf drop on the inner parts is normal, but yellowing of the outer leaves is a sign of a problem.
May
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • Pruning: This is one of the best times for main pruning. A second pruning can be done at the end of summer.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Good time for planting and transplanting.
  • Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves. Check the branches and trunk for brown, immobile bumps (scale insects).
June
  • Watering: In a long drought, water deeply once a month.
  • Pruning: Do shaping and hedge pruning. On hedge forms, light tidying is done at the start of the growing season. In uniform pruning, one third of the year's growth is cut back. Conifer branches do not produce new shoots when cut; therefore the cutting limit must pass through green branch.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Take care that the plant does not become stressed in extreme temperatures.
  • Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves.
July
  • Watering: In midsummer, deep watering every 15-20 days is enough. Established plants (over 2 years old) do not need watering in most years. The root zone should be wetted to a depth of 30-40 cm.
  • Pruning: For the second pruning, it is better to wait until the end of the month or early September.
  • General care: Make sure the plant's interior receives enough air.
August
  • Watering: In midsummer, deep watering every 15-20 days is enough. Established plants (over 2 years old) do not need watering in most years. The root zone should be wetted to a depth of 30-40 cm.
  • General care: The plant gradually prepares for winter.
  • Pests & diseases: Check the general health of the plant.
September
  • Watering: In a long drought, water deeply once a month. Water newly planted specimens more often than established plants during the first year; the root system is still shallow.
  • Pruning: Do the last formative pruning of the season; do not let it put out new shoots before frost.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Good time for planting and transplanting.
  • Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves.
October
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • Pruning: Do not prune except in emergencies.
  • General care: Good time for planting and transplanting.
  • Pests & diseases: Make sure water does not collect in the root zone with the autumn rains.
November
  • General care: The plant enters winter dormancy. This is a suitable month for planting new young plants.
December
  • Pruning: Only if really necessary, light corrections are made.
  • Plant protection: You can plan for dormant oil application.
  • General care: Evergreen leaves continue to lose water in winter. Water thoroughly once before the soil freezes.

The care advice on this page is general and for information only; it is not professional advice. Plant age, soil and your garden’s microclimate can change the outcome. Plant protection products are mentioned only as general information; they are regulated, and the choice, dose and timing must be decided by a qualified professional under local rules. Consult a landscape architect or agronomist before applying.

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