He's spent more than five decades searching for, breeding and developing some of the world's best clematis.
Expert grower and genial gentleman Raymond Evison, who has championed compact and highly rewarding cultivars suitable for containers and smaller spaces, is now looking for maximum impact with his latest Chelsea showstopper.
How can you achieve success with compact clematis?
Raymond shares his tips.
1. Don't use a plastic pot.
It will heat up too much during the summer and won't give the clematis any root protection.
2. Get the right size container
The container should be a minimum of 45cm (18in) deep and the same diameter. A plant in that pot size should be OK for around five years before transplanting it to a larger pot.
3. Check drainage
Good drainage is important. Use John Innes No 3 mixed 50:50 with a multipurpose compost.
4. Don’t grow it in too much sunlight
Clematis don't like their roots in the sun so if you are growing clematis in a container, surround it with summer bedding plants in the top of the pot to give added interest and colour and create its own microclimate.
Remove the top 3in (10cm) of compost, replacing it with fresh, when you take out the bedding plants at the end of summer.
Plant the strong-coloured clematis in the sun and paler shades in the shade. Those which grow in a shaded area only need three to four hours of good strong sunlight per day.
5. Plant them deep enough
Plant new plants deep - an extra 6cm (2-3in) deeper than the pot that it came in.
They are climbing perennials and need to build up roots down below.
Planting more deeply can help prevent large-flowered varieties from succumbing to clematis wilt.
For the best results, grow clematis through other plant material such as roses, ceanothus, pyracantha. If you want to grow it up a wall, grow it through other plant material.
6. Dealing with clematis wilt
If the plant gets clematis wilt, cut it down and, if you have planted it deeply, there's a good chance it will grow back.