Repotting guide

When & how to repot Rocky Mountain Juniper (Juniperus scopulorum)

Also called Rocky Mountain Juniper, Colorado Red Cedar.

More about rocky mountain juniper

About Rocky Mountain Juniper

Juniperus scopulorum · also called Rocky Mountain Juniper, Colorado Red Cedar · flowering

Rocky Mountain Juniper is a cold-hardy western conifer with soft blue-green scale foliage, valued as bonsai for its natural deadwood and reddish, shredding bark. An outdoor tree native to high, dry mountain country, it needs full sun, gritty fast-draining soil, and a proper winter chill. Overwatering and indoor keeping are its main downfalls.

Mature size: A small tree to 5-12 m in the wild; as bonsai usually maintained between 20 and 70 cm.

Watch for — Overwatering and root rot: Constantly wet soil rots the roots and yellows the foliage. Use a sharply draining mix and let it dry between waterings.

How to tell rocky mountain juniper needs repotting

Repotting on a calendar is less reliable than reading the plant. For rocky mountain juniper, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot rocky mountain juniper

Every 2–3 years, into bone-dry mix. Rocky Mountain Juniper's growth habit — slow to moderate evergreen conifer, naturally upright to irregular and often picturesquely twisted; produces fine blue-green scale foliage and characterful weathered deadwood with age. — sets the pace. Rocky Mountain Juniper is a cold-hardy western conifer with soft blue-green scale foliage, valued as bonsai for its natural deadwood and reddish, shredding bark. An outdoor tree native to high, dry mountain country, it needs full sun, gritty fast-draining soil, and a proper winter chill. Overwatering and indoor keeping are its main downfalls.

What size pot to step rocky mountain juniper up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Rocky Mountain Juniper stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot rocky mountain juniper

Spring or summer, while rocky mountain juniper is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting rocky mountain juniper

Repot dry. Do not water rocky mountain juniper for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty gritty, free-draining bonsai mix ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set rocky mountain juniper at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep rocky mountain juniper completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for rocky mountain juniper

Rocky Mountain Juniper wants gritty, free-draining bonsai mix. A blend of akadama, pumice and lava (about equal parts) or a coarse conifer mix gives the drainage and oxygen the roots need. Avoid moisture-retentive, compacted potting soils. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting rocky mountain juniper — frequently asked questions

How often should you repot rocky mountain juniper?

Every 2–3 years, into bone-dry mix for rocky mountain juniper. Repot rocky mountain juniper every 2–3 years into a snug pot of gritty, free-draining bonsai mix, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does rocky mountain juniper need?

When is the best time of year to repot rocky mountain juniper?

Should you water rocky mountain juniper after repotting?

No — not straight away. Repot rocky mountain juniper into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise rocky mountain juniper after repotting?

Not immediately. Wait about 3 weeks after repotting rocky mountain juniper. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.