Rheingold arborvitae

Sun

Full sun to light partial shade; the strongest gold colour develops in sun. In hot locations, light afternoon shade can reduce scorching.

Water

Keep the root zone evenly moist but not waterlogged. Water established plants during prolonged dry spells; this is not a drought-tolerant shrub.

Soil

Moist, well-drained loam or clay loam, from slightly acidic to alkaline. Avoid very dry, shallow soil and sites that remain waterlogged.

Height

3-5 ft (0.9-1.5 m) after about 10 years; old, unpruned plants can eventually reach 8-10 ft (2.4-3 m)

Spread

3-5 ft (0.9-1.5 m), potentially wider with age

Foliage

Evergreen. Fine, soft juvenile foliage mixed with scale-like adult foliage. New growth is yellow to golden orange, becoming coppery or bronze in cold weather; shaded foliage is greener.

Growth

Slow, usually about 3-6 in (8-15 cm) a year.

Care needed

Low

• Cold hardy
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.6 ft (0.5 m)

2. After 1 year

   1.9 ft (0.59 m)

3. After 2 years

   2.2 ft (0.68 m)

4. After 3 years

   2.5 ft (0.76 m)

5. After 5 years

   3 ft (0.94 m)

About 8 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Native to

the US and Canada

Growth rate

Slow

• Water deeply during the first two growing seasons whenever the upper soil begins to dry.
• Spread 2-3 in (5-8 cm) of organic mulch over the root area, keeping it clear of the stems.
• Feed lightly in spring with a balanced slow-release fertiliser only if growth is weak or the soil is poor.
• Choose a site sheltered from drying winter winds and away from road salt.
• Before the ground freezes in cold climates, water thoroughly if autumn has been dry.

Pruning. Little pruning is needed; lightly trim fresh growth in late spring or early summer if you want a neater outline. Do not cut back into bare, old wood, which usually does not regrow.

Early spring

Check for winter damage and remove dead or broken shoots once healthy growth is clear.

Spring

Plant while the soil is workable, refresh mulch and feed lightly only if needed.

Late spring

Lightly trim new growth if shaping is necessary, keeping all cuts within leafy growth.

Summer

Water deeply during dry spells and inspect browning foliage for mites or bagworms.

Autumn

Water during dry weather; normal shedding of some older inner foliage does not need treatment.

Winter

Gently brush off loose, heavy snow without pulling branches; leave ice to melt naturally.

• Use as a golden focal point among dark green evergreens.
• Repeat loosely rounded plants along a path or border for rhythm without formal clipping.
• Plant in foundation beds with enough space for its eventual width and taller, conical outline.
• Combine with purple-leaved shrubs and low blue-flowered perennials for foliage and flower contrast.

Garden styles it suits: Traditional, Formal, English country, Winter interest, Small-space and Low-maintenance.

Plant it with: Japanese barberry, Coral bells, Siberian iris, Dwarf fountain grass, Catmint and Japanese spirea.

Wildlife: Dense foliage can shelter small birds. Deer readily browse arborvitae and can severely damage this small cultivar, especially in winter.

• Drought and winter burn: exposed foliage browns when roots cannot replace lost moisture. Mulch, water during dry periods and shelter from drying winds; wait for spring growth before removing damaged shoots.
• Spider mites: fine stippling, dull foliage and webbing can develop in dry conditions. Check by tapping a branch over white paper; wash foliage thoroughly and use a labelled horticultural soap if needed.
• Bagworms, particularly in parts of North America: hanging bags contain foliage-eating larvae. Remove bags by hand before eggs hatch; treat small, actively feeding larvae with an appropriate labelled product if necessary.
• Root rot in wet soil: persistent browning and dieback may follow waterlogging. Improve drainage and replace badly affected plants rather than repeatedly watering them.

Treat the foliage, twigs and especially concentrated essential oil as toxic if swallowed by people, cats, dogs or horses. They contain thujone and related compounds; ingestion can cause digestive upset, while substantial exposure or swallowed oil can cause serious poisoning, including neurological effects. Sap or foliage may also irritate sensitive skin.

• Golden Globe arborvitae (Thuja occidentalis 'Golden Globe')

  Usually remains more rounded and has more obviously flattened sprays of scale-like foliage; Rheingold has softer juvenile foliage and becomes broadly conical with age.

• Fire Chief arborvitae (Thuja occidentalis 'Congabe')

  Generally stays smaller and more rounded, with stronger orange-red seasonal colouring. Young plants can be difficult to distinguish without a reliable label.

• Golden Mop false cypress (Chamaecyparis pisifera 'Golden Mop')

  Has conspicuously thread-like, drooping golden foliage rather than Rheingold's short, soft shoots and scale-like sprays.

Thuja comes from an ancient Greek name for an aromatic tree, occidentalis means western, and Rheingold is German for Rhine gold.

Propagation. Take semi-ripe cuttings with a small heel in late summer and root them in a free-draining medium under humid conditions. Seedlings will not reliably retain the cultivar's colour and shape.

Accepted botanical name

Thuja occidentalis

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Connecticut, Illinois, Indiana, Kentucky, Maine, Manitoba, Maryland, Masachusettes, Michigan, Minnesota, New Brunswick and New Hampshire.

Measured

Soil pH 5.2 to 7. Average height 1460 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.