by Dr John Howells

First published in Garden News, May. 16th 2002

The groups that I am recommending flower in mid and late summer. They are all easy to grow. I have left out the group that flowers in early summer, the Early Large Flowered group ('Nelly Moser' group). This is because, as the early gardeners suspected, recent systematic investigation has shown that this group, and only this group, wilts. That lovely group calls for special management.

The Late Large Flowered Group (Jackmanii Group)
I call this the 'tea-plate' group because the flowers can be the size of a tea-plate. The plants are vigorous and are large, often with hundreds of blooms. I shall start off with a corker - 'Victoria'. Possibly this is the finest of all clematis. It has deep mauve petals with a rosy central bar. It is very reliable, makes a lot of flower and is very showy. Glorious with yellow roses. 'Perle d'Azur' is the world's most popular clematis. It can sometimes be the size of a montana. Has a light blue colour that is violet in fact. Has been known to be a bit slow to start but don't let that deter you.
'Hagley Hybrid' is one of the easiest clematis to grow. If you can't grow this one you had better give up growing clematis. It is a lovely show of pink when it first opens but loses some colour with time. So it is best grown in a little shade. Also makes a good container plant. 'Gypsy Queen' has been with us a long time and it is a showy, reliable, flower. The colouring is deep mauve with a dark centre. Climbs up to 10ft (3m). 'Comtesse de Bouchaud' has been a favourite for a hundred years. It has a lovely pink flower that fades a little as the flower matures. 'Madame Edouard Andre' is one of the best of the reds and flowers over a long period.

The Viticella Group
The Viticella group I call the 'Easy' group. The original plant came to this country in 1569. This lovely wild plant is strong, and slightly scented. William Robinson suggested that we should scatter seeds of this in all our hedges. What a wonderful idea. Grow it. 'Margot Koster' flowers over a long period and has a lovely pinky-red colour. 'Etoile Violette' has showy deep purple flowers with contrasting creamy stamens. It flowers early. A very fine plant. 'Madame Julia Correvon' flowers early. The flowers are rich red with creamy stamens. This is such a strong grower that if you cut it to half its height after first flowering it will flower again for you. 'Abundance' really lives up to its name. It has attractive red petals with a violet tinge and a ruffled surface. 'Minuet' is one of the dancers of the clematis world. Its flowers are a most attractive white with a pink edge. There are other dancers in this group - 'Tango' and 'Foxtrot'. You may need one strong plant to flower in the autumn. This is 'Blue Belle'. It has a purple flower with contrasting yellow centre. A strong plant. There are many more plants in this group and none will disappoint.

The Texensis Group
I call this the group of 'climbing tulips'. These flowers have really lovely trumpets. 'Etoile Rose' flowers first. The petals are pinky-red with a broad silvery-white margin and the trumpet hangs down. Long flowering and can climb to 12ft (3.5m). The 'Duchess of Albany', on the outside of the tulip, has a white area suffused with pink, with a pink edge. The inside of the bell is pinky-violet. Like most of the flowers in this group it has a fine thick stalk and points upwards. 'Lady Bird Johnson' is dark red with a broad silver stripe on the outside of the tulip. The inside is deep red with crimson central stripe. 'Princess Diana' is possibly the finest in a really fine group. Outside the tulip is a vivid pinky-red with a silvery-white edge. Inside the tulip is a vivid pinky-red which is lighter at the edge. 'Gravetye Beauty' is last to flower. The outside of the tulip has a broad central crimson stripe with a silvery edge. The inside of the tulip is crimson.

The Orientalis Group
This is the only group to produce yellow clematis. It is also famed for its lovely seedheads. I shall give pride of place to 'Golden Tiara'. This comparatively new clematis has really taken off. It has nodding flowers with dark purple centres and is a strong grower, up to 10ft (3m). 'Bill MacKenzie' is another excellent plant and very popular. It flowers for a long time. The bloom and seed heads come together. It can cover a very big area, up to 20sq ft (6sq m). 'Aureolin' is another very reliable plant with nodding flowers. 'Helios' is different from the majority in that it only makes a small plant, so it is fine for a small garden, growing up to about 5ft (1.5m) and it starts its growth earlier than most in this group. It is also scented. 'Rehderiana' is different from the previous clematis as it has pale yellow nodding bells that hang in clusters. It is also wonderfully scented. It can make a very big plant, up to 20ft (6m). It is quite spectacular given plenty of room, but does not flower for a long period.

No fussing is required here. Plant as you would any shrub. End up with the crown of the plant about 2in (5cm) below the surface. The myth of planting clematis deep came from Rowland Jackman who, with his grafted plants, tried to produce extra plantlets from the stalk buried deep. He thought this was a safeguard against stem-rot (clematis wilt). Time has shown that it does not protect against wilt, and there are easier ways of coping with wilt. In any case, only one group wilts, and of course there is no sense in planting the other eleven groups deeply. All these groups can handle a cold winter.

All four groups have flowers that are borne on stems made that year. Therefore the four groups need to be pruned early in the year so as to produce strong growth that will produce many flowers that year. Don't fiddle. Prune right to the ground. What you are after here is to get new growth right from the crown of the plant. The only exception is an Orientalis that might make a small tree. In this event clip back to the main stems.

These plants can cover walls, fences, arches and pergolas. They are also lovely climbing into small trees and shrubs.

The plants in all these groups make a lot of growth every year. Therefore they do need fertilising. If you have it, give them a dose of manure in the autumn or late winter. Keep it well away from the crown of the plant. If not use compost. A handful of 'Growmore' in late winter around the plant is useful. Later, give a handful of Potash rich fertiliser which will stimulate the production of flowers. Keep all fertilisers well away from the crown of the plant.

Like all clematis these groups need to be well watered. A seeping pipe is excellent. Mulch with black plastic or mulching material.

The groups do not suffer from stem-rot (clematis wilt). In a bad year they could have attacks of powdery mildew. Most likely to suffer are the Texensis group. Here it is worthwhile to spray with fungicide as soon as the buds appear, or even earlier if there is any sign of the powdery mildew. Repeat every two weeks.

Reproduced by kind permission of Garden News.

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