Arizona cypress

Arizona cypress: how do you recognise it?

Habit

Conical to narrow tree about 12 m tall and 4 m wide, with upright branches.

Foliage

Fine, scale-like leaves on flattened twigs, blue-grey to silvery blue, aromatic.

Cones

Round, woody cones 2–3 cm across that often stay on the tree for years.

Flowers

Inconspicuous male and female flowers on the same tree; no ornamental value.

Scent

The foliage smells resinous and aromatic, especially when crushed.

Plants: April–May and September · Pruning: April

Why grow it?

• Blue-grey to silvery blue foliage all year, a lovely contrast with green garden plants.
• Tolerates heat and drought, ideal for warm, sunny, free-draining spots.
• The aromatic foliage gives a fresh scent, especially on warm days or when rubbed.
• Grows fairly quickly and so forms a windbreak or a tall green wall.
• Woody cones and dense branches give birds shelter.

Arizona cypress: where does it grow best?

• Full sun: in shade it becomes open and loses its blue colour.
• Free-draining soil, preferably sandy to loamy; acid to chalky. Heavy, wet clay is best avoided.
• Dry to at most normally moist: wet feet are fatal.
• Shelter it from cold, drying easterly winds, especially while it is young.
• Allow 3–4 m of space for a specimen and 1–1.5 m between plants for a hedge.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry

Size

12 m tall, 4 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Lavender: Same sunny, dry spot; purple flowers beside the blue foliage.
• Rosemary: Aromatic shrub for the same warm, free-draining soil.
• Rock rose: Flowers freely in the sun and likes the same dry soil.
• Blue fescue: Echoes the silvery blue of the foliage and stays low.

Arizona cypress: when and how to plant it?

Plant in April–May and September.

1. Plant in April–May or in September, when the soil is warm enough to root quickly.
2. Dig a hole twice as wide as the root ball. Mix heavy soil with sand or grit to improve drainage.
3. Set the plant at the same depth as in its pot, preferably slightly raised, so water does not collect around the trunk.
4. For tall plants or windy sites, fit a stake and tie the trunk loosely.
5. Water in generously straight away and keep the soil lightly moist in the first year.
6. Spread a thin layer of coarse mulch (bark or gravel) at the base, keeping it clear of the trunk.

Care

Water

In the first year, water regularly in dry spells. After that it usually manages on its own; too much water is worse than too little.

Feeding

Hardly needed. On poor soil, give a little organic fertiliser or conifer feed in spring.

Mulching

A thin layer of bark or gravel suppresses weeds; keep it clear of the trunk.

Support

Tie young, tall plants loosely to a stake; they can topple in a gale.

Tidying

You can leave the cones and dead twigs on or remove them in spring.

Tip: Plant it in sun on free-draining soil and only lightly trim the young shoots in April. What you cut into old brown wood does not grow back.

Arizona cypress: when to prune it?

Pruning months: April.

When: In April, lightly, before or just as new growth begins.

How:

• Trim only the young green shoots: one light formative trim a year is enough.
• Remove dead or damaged branches to keep the plant airy.
• Take out broken tops; on a specimen, reduce a double leader to one.
• For a hedge, trim the new growth each year, slightly narrower at the top than at the base.

Caution: Never cut into old brown, leafless wood: a cypress does not regrow from it and you are left with a bare hole.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Sow in spring in a sandy mix; seed from the cones germinates, but seedlings vary in colour and shape.

Cuttings

Semi-ripe cuttings in August–September, in sand and potting compost. They root slowly and not always; cultivars are propagated this way or by grafting.

Arizona cypress: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C; in Belgium that is usually enough in a sheltered spot.
• Damage mostly comes from cold, drying easterly winds and waterlogged soil; young plants may get some protection (a hessian screen) in their first winters.
• Do not cut off browned tips straight after a hard winter: wait until spring to see what greens up again.

Diseases and pests

• Browning: Brown tips or bare patches after severe frost, cold wind or prolonged drought. Wait until spring and cut dead wood back to green; old brown wood does not regrow.
• Root rot: The whole plant suddenly turns brown, especially on wet, compacted soil. Prevent it with free-draining soil; affected plants usually cannot be saved.
• Cypress canker: Brown, resinous cankers on branches and dying branches. Cut affected branches back well and disinfect your secateurs. Mostly occurs in warmer regions.
• Spider mites: Fine webs and yellowing tips in hot, dry weather. Spray firmly with water now and then and choose a slightly airier spot.

Through the year

• March: Look at winter damage; do not cut yet.
• April: Plant. Trim lightly and remove dead branches.
• May: Plant. Water young plants in dry weather.
• June: Water young plants in dry weather.
• July: Water young plants in hot weather.
• September: Plant. Last chance to plant before winter.
• October: Shelter young plants from wind.
• November: Check the stake and ties.
• December: Rest. Shake heavy snow off the branches.

Did you know?

• The Arizona cypress belongs to the same genus as the famous Italian cypress of Tuscany.
• The round, woody cones are 2–3 cm across and can hang on the tree for years.
• In the southern United States it is also grown as a Christmas tree.