Thor – dark red climbing rose for professional own-root production
Thor delivers vertically dominant structures with dense, dark foliage and very full, large flowers in an intense, velvety dark red that holds its visual strength without marked fading, making it highly suitable for exclusive, space-defining installations on arbours, pergolas, walls and fences. As pharmaROSA® NEONATAL own-root material it offers a stable propagation base for nursery networks seeking predictable, long-lived stands that regenerate well under continuous production loads, supporting homogeneous batches and low replacement over successive cropping cycles. Its combination of proven disease resistance and H7-rated winter hardiness to around -21 °C underpins reliable supply for UK projects where winter and wind exposure are relevant, while the recommended trained climber route in 5–7 L containers allows you to receive staked, pre-trained plants with 3–5 main canes, ready for rapid finishing and alignment with retail and reseller premium vertical-garden assortments. In production scheduling terms, own-root development from Year 1 root establishment through Year 2 structural shoot building to Year 3 full ornamental value can be planned into long-term capacity and contract work.
Usage options
Finished-product ideas
- 5–7 L trained climber for premium retail – Own-root, staked plants with 3–5 canes and dense dark foliage presenting deep velvety red blooms as a vertical garden feature on walls or fences – target: branded retail / reseller climber ranges.
- Pergola pair set for feature entrances – Matched 5–7 L trained climbers positioned for pergolas or arbours, using hardy, disease-resilient stock to ensure consistent structure and colour impact – target: garden centres and project-oriented nurseries.
- Collection-garden vertical specimen line – Own-root NEONATAL-derived climbers allocated to thematic and show-garden collections where stable identity, hardiness and distinctive dark red colour are priorities – target: botanic and collection gardens.
- Cut-and-climb dual-purpose stock – Trained 5–7 L climbers grown for wall/pergola use while providing large, very full flowers suitable for occasional cutting from robust, low-maintenance plants – target: specialist nurseries and florist-linked growers.
- Cold-region climber assortment module – A climber module anchored by this hardy, disease-resistant, deep red variety, produced as trained 5–7 L plants for regions with stronger winter and wind exposure – target: regional wholesalers and integrator networks.
Technical cultivar profile
| Parameter |
Data |
| Name and registration |
Thor, a large-flowered climbing rose from the Climbing rose collection, used commercially as a climbing rose type; registered cultivar name Thor with American Rose Society exhibition name Thor. |
| Origin and breeding |
Bred by Michael Henry Horvath in the United States in 1940 from the cross ‘Alpha’ × ‘President Coolidge’, introduced in the USA in 1940 by Wayside Gardens after development at Mentor Avenue Nursery. |
| Growth and structural characteristics |
Vigorous climbing habit with dense, slightly glossy dark green foliage, height around 300–460 cm and spread 200–320 cm, forming strongly armed, densely thorned canes suitable for training onto supports. |
| Flower morphology |
Large, very full solitary blooms with 40 or more petals, ball to pompon shaped, remontant but with a less prolific second flush, and weak self-cleaning so spent blooms may need deadheading in finished production. |
| Colour data and phenology |
Dark burgundy buds open rich deep crimson, then intense saturated carmine red with velvety inner petals, showing a subtle bluish toning and purplish-red tip, with moderate colour retention and little obvious fading. |
| Fragrance and aroma |
Mild, restrained fragrance combining sweet and spicy elements, providing a discreet scent presence without overwhelming nearby planting schemes or strongly defining the cultivar as a fragrance-led product. |
| Hip characteristics |
Produces moderately abundant, ellipsoidal dark red hips around 12–18 mm in diameter, adding a secondary seasonal interest where hips are retained and not fully removed through deadheading practices. |
| Resistance and winter hardiness |
Rated disease-resistant to powdery mildew, black spot and rust, with hardiness to about -21 to -18 °C, aligning with RHS H7, Swedish Zone 3 and USDA Zone 6b for robust performance in colder temperate sites. |
| Horticultural recommendations |
Recommended as a trained climber finished product in 5–7 L pots, suited to arbours, pergolas, fences, walls and cut use, with generally low maintenance requirements and minimal intervention under normal conditions. |
Thor offers vigorous vertical growth, dense foliage and disease-resilient, hardy performance on a predictable own-root base, making it a dependable choice for long-lived climbing ranges where we can jointly plan volumes and timing.
