Happy Anniversary Clematis Plants

• Variety: Happy Anniversary, pruning group 2 – compact, long-flowering, container-friendly
• Latin name: Clematis 'Happy Anniversary'
• Flower: Deep blue, 10–12cm across
• Scent: None
• Climbing method: Leaf-stalk tendril climber
• Height: To 1.5m
• Flowering: May–August
• Pruning group: Group 2 – light prune in February (or cut hard for simplicity — see FAQs)
• Planting depth: Plant 8–10cm below pot level
• Hardiness: Fully hardy
• RHS AGM: No
• Sold as: P9 and 3L deep pots. Peat-free compost
• Plant outdoors: Year-round
• Delivered: March–November typically. Collection from Castle Cary also available

Happy Anniversary Clematis – A Big-Flowered Clematis for Small Spaces

Happy Anniversary is one of Raymond Evison's compact clematis, bred specifically for containers and small gardens. It reaches about 1.5m — roughly half the height of a standard large-flowered clematis — which makes it right for a patio pot, a balcony railing, or the front of a border where a full-sized clematis would overwhelm everything around it. The flowers are deep blue, 10–12cm across, and produced over a long season from May into August. That combination of big flowers on a small plant is what Evison has spent decades perfecting.

It is technically Group 2, flowering on short shoots from last year's wood with a repeat on new growth. But Evison himself recommends a simpler approach for container-grown plants: cut all stems to about 15cm in late winter. You sacrifice the early spring flush but get reliable, tidy summer flowering without having to untangle which stems are old and which are new. In a pot on a patio, this makes life considerably easier.

Compact Clematis on the Patio

At 1.5m, Happy Anniversary sits well on an obelisk in a 40cm pot, a low trellis against a sunny wall, or a half-barrel planter by a doorway. For a container combination, pair it with The Vagabond (another compact repeat-flowerer, this time in purple-violet) or Piilu (pink-striped, similarly compact). In a border, it works at the feet of a climbing rose or trained through a low shrub. Add lavender at the base to shade the roots and provide the fragrance that clematis never quite manage.

Why Ashridge?

Every clematis we sell is guaranteed, packed by our Somerset team, and delivered by next-day courier. Which? Best Plant Supplier, Feefo Platinum Trusted Service, and real people on the phone if you need advice. See the full clematis range.

Frequently Asked Questions

Can Happy Anniversary grow in a pot?

One of the best clematis for containers. At 1.5m, it doesn't outgrow a patio obelisk, and the compact habit keeps it manageable. Use a pot at least 40cm across and deep, with drainage holes. Plant 8–10cm below the rim of the compost (the same deep-planting rule applies in pots). Water regularly and feed fortnightly from April to September.

How should I prune Happy Anniversary?

Two options. The traditional Group 2 approach: in February, cut each stem to the first pair of fat buds from the top — this preserves last year's wood for an early flush. The simpler approach, recommended by breeder Raymond Evison for container-grown plants: cut all stems to 15cm in late winter. You lose the early flowers but get a tidier, more reliable summer display. Our pruning guide explains both.

How deep should I plant Happy Anniversary?

Plant 8–10cm below pot level, whether in the ground or in a container. Deep planting gives the plant underground buds to regrow from if the top growth is damaged. See our planting depth guide for the detail.

Is Happy Anniversary resistant to clematis wilt?

No large-flowered clematis is truly wilt-resistant. Deep planting is the best defence. For a compact clematis that is effectively wilt-immune, you would need to look at the viticella types, but these tend to have smaller flowers. The trade-off with Happy Anniversary is big flowers with some wilt risk — which deep planting largely manages.

Does Happy Anniversary repeat flower?

The main flush runs May to June on old wood, followed by a second show from July into August on new growth. If you use the hard-prune method, you get one extended display from June to August instead. Either way, the total flowering season is long for a large-flowered clematis.