How to grow clematis
Fabulous flowers for every outdoor space
Clematis is a beautiful and versatile flowering perennial climber which can add elegance to any aspect of your garden. With a bit of careful planning you can have them flowering from early spring to late autumn. The flowers range in size from a couple of inches to huge plate sized blooms. They are available for every aspect and even if you don’t have a garden there are varieties which are quite happy in a container. They can range in height from a couple of feet to covering a house so choose carefully. The smaller growing varieties look fabulous falling out of a tall classical urn.
Most of them need sunshine, at least 6 hours a day, but there are varieties which will flower in partial shade so it pays to buy from a reputable supplier who will be able to advise which one is the best for your location. They need cool roots so if you are growing one in a container make sure it is large enough to provide a good root space, at least 18 x 18ins. Place other planted containers around the pot to ensure the sun does not hit the side of the clematis container.
Evergreen clematis are not completely hardy so must be planted in a south facing sheltered position which receives sun all day. If frost is forecast it would be advisable to cover with horticultural fleece until the threat has passed.
They need a good humus rich soil which holds moisture but doesn’t become sodden in winter. If you have a sandy or clay soil add some good quality peat-free compost, such as Lakeland Gold, or home-made compost. If planting in a container use John Innes No 3 mixed with a good quality peat-free compost.
Dig a hole slightly deeper than the pot the clematis is in and add some slow release general purpose fertiliser. Plant the clematis so it is slightly deeper than the pot it comes in, fill the hole with the soil and firm in making sure there are no air pockets. Water well and cover the soil surface with a mulch of chipped bark to a depth of 2 – 4ins. Click here to read the blog giving you tips on how to mulch your garden. If planting in a container cover the drainage hole with a couple of pieces of broken crock to prevent it blocking with silt.
Make sure it is well watered in the first year of planting and thereafter in times of prolonged dry spells. If the clematis is planted in a container it may need to be well watered every day if the temperatures are high.
If you haven’t mulched your soil spring is the time when you can mulch with well-rotted farmyard manure, keep it away from the plant stem just in case it burns the clematis. Feed in spring with a slow release general purpose fertiliser then once it starts to form buds use a high potash feed every week, such as Tomorite, as this encourages the formation of more flower buds.
Most clematis need some sort of support and this can be as simple as a wigwam of bamboo canes or elaborate as an arbour with a seat; check out our selection of arbours and arches here. Some of the smaller clematis look spectacular planted in a tall slim container and then just left to sprawl down the pot. Add height and structure to an herbaceous border with a clematis growing up a wooden or wrought iron obelisk; click here to read the blog giving you some tips on how to create interest in your herbaceous border by adding height.
This can be quite complicated as clematis are divided into groups and pruned at different times of the year accordingly, so it is important to know which group your clematis belongs to, it usually states this on the label.
Pests and diseases
Clematis are generally healthy but the large summer flowering varieties very often suffer from clematis wilt. This is usually not a fatal condition, it will suddenly droop overnight. The remedy is to chop it off at the base then pile about 3ins of fresh bagged compost over the top, then it will throw out new healthy shoots. Mildew can also be a problem, caused by dry airless conditions, so make sure you prune it at the right time to allow air to circulate through the plant, and don’t let it become dry. If it does get mildew cut out the infected stems and pick up any shed leaves. Don’t add the infected material to the compost heap but place in the grey waste bin not the green bin, which goes to make re-cycled compost, as it is not guaranteed to kill the mildew spores.
Bernadine This small climber is ideal for containers as it only reaches about 5ft. It’s delicate lavender large flowers are veined with pink and it has deep maroon stamens. Flowers all summer into early autumn.
Guernsey Cream Very tall so ideal for arbours and arches. It’s large pale cream flowers appear in early summer.
Piilu This is medium height, about 8ft, so ideal for growing up a fence or obelisk, also suitable for a container. It has large flowers in pale and dark pink with wavy edges which appear in late spring/early summer, it sometimes produces a second flush of flowers late in the season on new growth.
Josephine Produces large double pink flowers in summer and is suitable for a large obelisk, fence or arch.
Hagley Hybrid Produces masses of mid pink flowers over the summer. Only reaches about 8ft so ideal for tumbling down a tall container or classical urn or up a large obelisk or trellis.