How-To: Grow Clematis

How-To: Grow Clematis

Clematis are climbing perennials that generally are grown on a trellis, arbor, arch or supported by a shrub or upright evergreen. Clematis will grow in full sun to part shade. More importantly, their roots must be kept cool, so grow them either in the shade of a small shrub such as potentilla, or with the ground mulched with two inches of bark or peat. 

Soil Prep

Clematis form an extensive root system and require lots of water and nutrients. Dig a large hole, about 45cm x 45cm x 45cm. Add roughly 2 buckets of peat moss to the top soil along with compost or composted manure and a handful of bone meal. Make sure to mix all of the new ingredients very well with the existing topsoil. Remember, the extra effort put into soil preparation now will pay back many times over in the years to come. 

Planting

Set the Clematis into the planting hole so 5-10 cm of the stem above where the roots start will be below ground level. Fill the hole back in with your soil mix. Soak well with ½ strength fertilizer that encourages flower production like a 15-30-15. Let water soak in and then finish the planting. Remove support stick and prune back to a set of buds at a height of 30cm above ground level. Pruning stimulates good root growth. 

Clematis Varieties

Purple Clematis

C. Guiding star

Medium sized dark royal purple, pointed sepals with reddish-purple streaks which tend to tone in with the overall colour. Free flowering vine of medium vigour, requiring moderate pruning, can be cut back to 60 to 120 cm, if vines become overgrown.

C. Gypsy Queen

Large velvety violet-purple, somewhat like Jackmanii, except larger flowers. Summer blooming with vigorous growth habit, requires pruning back to 50 to 100cm.

C. Jackmanii

Deep velvet purple. Our strain of this old favorite is similar to the European Clone “JACKMANII SUPERBA”. This clematis makes vigorous rapid spring growth and commences blooming on the new growth the first week of July in the Niagara area. Can be pruned hard each year by cutting back to 30 to 90 cm. This is our hardiest and most popular variety.

C. President

Large flowering deep purple-blue with reddish-purple stamens, blooms are slightly cupped. This beautiful flower is quite vigorous when established and requires moderate pruning. Can be cut back to 60 to 120 cm, if vines become overgrown.

Blue Clematis

C. Elsa Spath

Rich lavender-blue, extra large flowers with pointed sepals and dark stamens. Prune lightly to shape the overall appearance during the first two years. After the plant is well established, prune each year by cutting back to 60 to 120 cm.

C. Lady Betty Balfour

Dark blue, with attractive creamy-white stamens, vigorous growing and very hardy. This superb variety requires hard pruning every March by cutting it back to 60 – 120 cm. This is a late flowering variety requiring a sunny location for a profusion of blooms.

C. Lawsoniana

Lavender-blue with a rosy tint, long pointed sepals, pale brown stamens, large flowers. Prune lightly in early spring.

C.Lord Neville

Dark blue large flowers with purple stamens and pointed wavy-edge sepals. Only limited pruning is required to shape the overall appearance.

C. Mrs Cholmodley

Large light blue sepals with brown stamens. Large open type flowers and prolific long lasting blooms. Prune lightly when plant becomes overgrown.

C. Perle d’azur

Sky blue with green stamens, vigorous growth habit, free flowering with masses of medium sized flowers. Prune lightly when plant becomes overgrown.

C. Ramona

Very popular, large satiny lavender-blue, with dark stamens and rounded sepals, also known as Hybrid Seiboldi. Although this old favourite is quite vigorous, it requires little pruning. The plants need to be pruned only enough to improve the overall shape.

C. Tillicum

Very large, delicate bile with deep purple stamens. No pruning necessary unless plant becomes overgrown.

C. Vyvyan Pennell

Double violet blue flowers. Flowering in June on the previous year’s growth with sepals around the outside and a large rosette in the center. (Flowers resemble Peonies). Late in the year, flowers are mostly single, some semi-double on the new growth. No pruning required.

C. William Kennett

Deep lavender with dark purple stamens, a handsome variety, large flowers, pruning is optional, however, cutting back lightly is usually beneficial.

Red Clematis

C. Crimson King

A good red clematis with brown stamens, with a little more mauve tone than Ernest Markham. Flowers are medium in size and fairly early. Require only limited pruning to shape the overall appearance.

C. Ernest Markham

Large flowering, glowing petunia-red with golden stamens. The best red clematis for southern Ontario. This vigorous growing clematis can be cut back to 50 to 100 cm (20-40 in) in March, and it will produce masses of large flowers in late summer. If the old wood is not cut back, it will produce somewhat smaller flowers on the old wood in late spring. Ernest Markham prefers a sunny location, with the roots shaded and mulched.

C. Rouge Cardinal

Glowing crimson with brown stamens, medium sized flowers. Prune hard in early spring by cutting back to 50 to 100 cm.

C. Ville de Lyon

An abundance of carmine red blooms shading to deep crimson on the outer edges of the sepals; producing a profusion of medium-sized flowers. This very hardy, vigorous variety blooms in July and it can be pruned back to 30 to 90 cm each year in March.

Pink Clematis

C. Comtesse de Bouchaud 

Gracefully curved sepals ranging in tone from satin rose to mauve-pink with yellow stamens; medium-sized flowers bloom in great profusion in July. This vigorous clematis requires pruning back to 30 to 90 cm (12-36 in). 

C. Mme Baron Veillard 

A profusion of medium-sized lilac-rose flowers with yellow stamens blooming during late July and August. This vigorous growing clematis requires pruning back to 30 to 90 cm (12-36 in). 

C. Pink Chiffon 

Medium-sized pink flowers with burgundy stamens and pointed sepals. This free-flowering variety is also known as Hagley Hybrid. Limited pruning is sufficient. It can be cut back to 60 to 120 cm (24-48 in) when vines become overgrown. 

Mauve with White Bars 

C. Barbara Jackman 

A soft mauve with a violet-crimson bar and creamy stamens. This plant only needs enough pruning to improve overall shape. 

C. Bees Jubilee 

A deep mauve-pink with a deep carmine bar, often described as an improved Nelly Moser. This Variety flowers both on the old and new growth; needs pruning only to shape the overall appearance. 

C. Capitan Thuilleaux 

Broad strawberry-pink bars on a cream background; pointed sepals, golden brown stamens, medium sized flowers, (introduced by Fish’s in 1967). Prune in early spring by cutting back thin stems and removing dead wood. 

C. C.W. Dowman 

Pale pink with carmine bar and golden stamens. Medium growth habit. No pruning required. 

C. Dr. Rupple 

Deep carmine-pink bars upon light pink sepals, golden stamens, medium-large flowers, (introduced by Fish’s in 1975). Prune lightly in early spring. 

C. Mrs. N. Thompson 

Deep violet with a vivid scarlet bar and reddish stamens. Medium type growth habit which should be pruned lightly. 

C. Nelly Moser 

Large pale mauve with carmine bars; flowers are produced in amazing profusion. This variety tends to fade in full sun, but does exceptionally well in partial shade, such as an eastern exposure. Flowers both on the old and new growth, needs limited pruning to shape the overall appearance. 

C. Sir Garnet Wolseley 

Mauve-blue sepals with a purple bar. Early flowering, medium sized blooms have red-brown stamens. Prune lightly to shape plant. 

White Clematis

C. Duchess of Edinburgh 

Double white rosette-shaped flowers blooming in late spring followed by semi-double flowers in late summer on the new growth. Needs only limited pruning to shape the overall appearance. 

C. Henryi 

Unusually large white flowers with pointed sepals and dark stamens, growing often to 30 cm (8 in) in diameter. Henryi is a vigorous plant remaining bushy. Prune lightly to shape overall appearance. 

C. Huldine 

Medium-sized pearl-white flowers with a slight showing of mauve bars on the underside of the sepals. This very strong vigorous variety produces a mass profusion of flowers. It should be pruned every year by cutting back to 30 to 90 cm. 

C. Marie Boisselot –(syn. Madame-La Coulte

Pure white with yellow stamens, a beautiful flower with overlapping sepals, large flowering; prune lightly in early spring.