Clematis montana: how to grow and prune, plus the best varieties
Although known as vigorous plants, Clematis montana can be also be medium sized or even compact. Here are some recommended varieties from the National Collection at the garden of National Collection holder, Val Le Neville-Parry. Words by plant expert Andy McIndoe. Photographs Dianna Jazwinski
The National Collection of Clematis montana is held Val Le Neville-Parry at her garden By The Way in Salisbury, Wiltshire, and contains more than 200 plants in 50 named varieties and cultivars.
Some Clematis montana are rampant, reaching 8m or more, but clematis breeding has produced more compact varieties that are suitable for growing in smaller gardens, or even pots. For all types, flowering is longer than is often assumed, starting in early March and continuing into late June. All Clematis montana go on to produce fluffy seedheads in autumn and into winter.
Foliage is also a feature. “I love the leaves as much as the flowers,” says Val, who shares her recommendations here. Many are available commercially, although some can currently only be seen growing at By The Way.
How to grow Clematis montana
Medium and large Clematis montana
The more vigorous types of Clematis montana can reach 8m or more, with some of the fully vigorous cultivars reaching 10-12m, depending on growing conditions. These are versatile plants with many uses in the garden.
In her garden, Val uses a Clematis montana var. grandiflora to transform a laurel hedge running down one side of the garden; its shining white blooms, which are among of the largest flowers in the group, sit like butterflies on the glossy leaves of the laurel. Both clematis and laurel are pruned together and thrive on it. The vigorous Clematis montana var. wilsonii can be used as ground cover where space permits. It forms an undulating carpet of foliage studded with scented creamy-white flowers in early summer.
Compact Clematis montana
Many varieties and cultivars of Clematis montana have been bred to have a more contained habit that is less rampant than the vigorous ones. These compact montanas grow to around 4-7m, depending on cultivar and growing conditions, and are a great choice to grow over arches and obelisks. They can be grown on the trunks of mature trees or up poles to add vertical interest to a bed or border.
Compact Clematis Montana will also grow successfully in large pots (at least 50 litres) with a loam-based growing medium with regular watering and feeding with a slow-release fertiliser. Regular watering and annual feeding with a slow-release fertiliser are both essential.
Pruning Clematis montana
Clematis montana is in Clematis Pruning Group 1. It does not need regular pruning, but if is getting too large or leggy, cut it back after flowering, in spring. Regular pruning will encourage strong growth and good flowering and will ensure that the flowers remain at eye level, with no bare, tangled stems at the base.
The best Clematis montana to grow
Medium to large Clematis montana
Clematis. montana var. grandiflora
The hardiest and most reliable, fully vigorous montana. Open, pure-white blooms with primrose stamens create a stunning display over cascading stems from late spring. AGM. Hardiness: RHS H5, USDA 4a-9b. Height: 8-12m.
Clematis Giant Star (='Gistar')
A large-flowered cultivar, introduced from New Zealand. Cup-shaped blooms with waved tepals of mid-pink, paler at the edges eventually open flat and upward facing. A medium-growing montana. Height: up to 10m.
Clematis 'Victoria Welcome'
An elegant, medium-growing, single montana selected by Val. Its delicate dark-green leaves are matched by starry white, green-eyed blooms, reflexed at the tepal edges. Not yet available commercially.
A seedling of C. ‘Prosperity’ named after a friend of Val’s. The mauve-pink blooms open as tiny, cream-eyed stars but mature to open, blooms with the longest, narrow tepals in the group. Medium. Height: up to 8m.
Clematis 'Broughton Star'
Val is generally not as keen on the doubles, mainly because they prefer a richer soil, but she makes an exception for this medium-growing double. Fabulously floriferous, it has abundant dusky-pink, veined blooms that are displayed against dark, bronze-tinted foliage. Excellent to grow through a shrub or a small tree. AGM. Hardiness: RHS H5, USDA 7a-9b. Height: up to 8m.
Compact Clematis montana
Clematis montana 'By the Way'
A selected seedling that has proved to be one of the best singles. Blooming from the base to the tip, the medium-growing cultivar has soft-pink, deliciously fragrant open blooms that develop into seedheads remaining attractive throughout autumn. Not available commercially.
Abundant, semi-double flowers with creamy-white outer tepals, becoming pink; the narrow inner tepals darker. At its best in fertile soil and full sun, the flowers open later than single montanas. Height: up to 6m.
Clematis montana var. rubens 'Veitch'
Small, open blooms of square formation with rounded tepals of deep, mauve-pink with pale stamens. Best against a light background and seen at close quarters. Hardiness: USDA 7a-9b. Height: up to 4m.
Clematis 'Van Gogh'
Excellent cultivar that blooms early and continues for up to six weeks. Cherry-pink blooms, sometimes double at the end of the flowering period. Good choice for a large pot in a sheltered situation. Height: up to 4m.
Clematis 'Primrose Star'
Attractive compact cultivar that grows to around 6m. From New Zealand with fully double pale, lemon-yellow flowers, pink at the edge of the tepals. It needs a sunny spot and fertile soil. Height: up to 3.5m.
One of the best compact singles, which was discovered by Freda Deacon in her Suffolk garden and later introduced by nurseryman Jim Fisk. Probably a seedling from C. montana var. rubens ‘Pink Perfection’, it has open, lightly fragrant, mauve-pink blooms, which are darker at the edges and displayed against bronze-green leaves. AGM. Hardiness: RHS H6, USDA 3a-8b. Height: up to 4m.
Clematis 'The Jewell'
A compact cultivar and Val’s all-time favourite. It produces posies of apple blossom-like blooms, darker on the outside of the tepals, from late spring through to autumn. It is named after David Jewell at Sir Harold Hillier Gardens and has C. chrysocoma in its parentage. Height: up to 4m.
More information on hardiness ratings can be found here.