Rosemary 'Arp' (Rosmarinus officinalis 'Arp'): Cold-Hardy Rosemary for Northern Gardens

Overview

'Arp' is the most cold-hardy rosemary cultivar, surviving to -18°C (0°F) / USDA zone 6 with protection. Discovered in Arp, Texas, it combines classic rosemary flavor and fragrance with exceptional winter tolerance, making rosemary viable for northern gardeners.

Botanical Description

Upright, open shrub 1–1.5 m tall. Leaves are linear, gray-green, highly aromatic. Flowers are pale blue, in axillary clusters, blooming late winter to spring. Habit is less dense than 'Tuscan Blue' but more winter-resilient.

Taxonomy

Family:	Lamiaceae (lay-mee-AY-see-ee)
Genus:	Rosmarinus (rose-ma-REE-nus)
Species:	officinalis (oh-fiss-ih-NAH-liss)
Cultivar:	'Arp'

Growing Conditions

• Light: Full sun.
• Soil: Well-drained, alkaline, gritty.
• Water: Low; drought-tolerant.
• Hardiness: USDA zones 6–10 (zone 6 with winter protection).

Uses

All standard rosemary uses, plus reliable perennial performance in zone 6–7. Excellent for hedges, topiary, and container culture where it can be moved to protection.

Winter Care (Zones 6–7)

Mulch heavily. Plant in sheltered microclimate (south wall). Wrap with burlap if prolonged deep freeze expected. Container plants: move to unheated garage/cool porch.