Repotting guide

When & how to repot Arp Rosemary (Rosmarinus officinalis 'Arp')

Also called Arp Rosemary, Hardy Rosemary.

More about arp rosemary

About Arp Rosemary

Rosmarinus officinalis 'Arp' · also called Arp Rosemary, Hardy Rosemary · herb

Arp Rosemary is one of the hardiest rosemary cultivars, valued for cold tolerance down to USDA Zone 6 and its strongly aromatic, gray-green needle foliage. It forms an upright, shrubby mound perfect for herb gardens and ornamental borders. Grow in full sun with excellent drainage; drought-tolerant once established.

Mature size: 1–1.5 m tall, 0.9–1.2 m wide (3–5 ft tall, 3–4 ft wide)

Watch for — Root rot (Phytophthora, Pythium): The most frequent killer. Caused by waterlogged soil or pots without drainage holes. Symptoms include wilting despite moist soil, blackened stems at the base, and foliage that turns brown from the bottom up. Improve drainage immediately and reduce watering frequency.

How to tell arp rosemary needs repotting

Repotting on a calendar is less reliable than reading the plant. For arp rosemary, 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 arp rosemary

Every 2–3 years, into bone-dry mix. Arp Rosemary's growth habit — upright, bushy shrub with an arching, slightly open habit — sets the pace. Arp Rosemary is one of the hardiest rosemary cultivars, valued for cold tolerance down to USDA Zone 6 and its strongly aromatic, gray-green needle foliage. It forms an upright, shrubby mound perfect for herb gardens and ornamental borders. Grow in full sun with excellent drainage; drought-tolerant once established.

What size pot to step arp rosemary up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Arp Rosemary 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 arp rosemary

Spring or summer, while arp rosemary 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 arp rosemary

Repot dry. Do not water arp rosemary 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 sandy or gritty, well-draining, low-fertility 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 arp rosemary 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 arp rosemary 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 arp rosemary

Arp Rosemary wants sandy or gritty, well-draining, low-fertility. Prefers lean, alkaline to neutral soil (pH 6.0–8.0). Use a mix of horticultural grit and loam, or a cactus/succulent blend amended with perlite for container growing. Rich, moisture-retentive soils promote soft growth susceptible to fungal disease. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting arp rosemary — frequently asked questions

How often should you repot arp rosemary?

Every 2–3 years, into bone-dry mix for arp rosemary. Repot arp rosemary every 2–3 years into a snug pot of sandy or gritty, well-draining, low-fertility, 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 arp rosemary need?

When is the best time of year to repot arp rosemary?

Should you water arp rosemary after repotting?

No — not straight away. Repot arp rosemary 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 arp rosemary after repotting?

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