WHY IS MY CLEMATIS NOT FLOWERING? |The Garden of Eaden

Why is my clematis not flowering?

There is little that can compete with a clematis at the height of its flowering season, however there is certainly no guarantee of success. Some years even established specimens can be little hit and miss, and newly planted specimens can often appear to be holding back the 'fruits' of your labour. Deliberately some might say!

Why is my clematis not flowering?

Luckily, when it comes to growing clematis there is an old mantra that is often wheeled out,

'...keep the roots in the shade, keep the head in full sun...'

And there is a lot of sense to this. Many clematis species are woodland plants, and so they would begin the first 2-3 years of their life under woodland shade until they have grown tall enough to reach past the tree canopy. Once exposed to direct sunlight they accelerate foliage growth and produce enough energy via photosynthesis to bloom and subsequently produce seed.

Reasons why your clematis is refusing to flower

Why is my clematis not flowering?

1. The most common reason for a clematis not to flower is unsuitable growing conditions. As you would expect from their native environmental conditions, Clematis need a moisture retentive, but well-drained, soil with their roots kept in cool shade. If the soil above the roots is exposed to full sun then place stones or pebbles around the base of the plant, or grow another plant directly between it and the sun so that the roots are kept in shadow during the hottest part of the day.

Be aware that keeping the top growth in shade will impair both growth and flowering.

What can be done to encourage flowering?

If you have done everything correctly, as in the roots are in the shade and the foliage is in full sun, then consider an application of sulphate of potash. This is best applied in late winter or early spring.
Also as a general rule, clematis will perform best in a slightly acidic soil. Too acidic or alkaline soils can also discourage growth and flowering.

Why is my clematis not flowering?

2. If growing conditions are good and you have been feeding your clematis regularly since its introduction to the garden then the issue may be the application of too much nitrogen. Yes this will do wonders for the plants foliage but there is a tendency (particularly in young clematis plants) to produce foliage over flower production when overfed.

What can be done to encourage flowering?

Choose a fertilizer with a low nitrogen number relative to the phosphorus number, such as 5-10-10, so that your plant will develop blossoms and roots, rather than lots of foliage. Common to all general fertiliser, they have phosphorus to develop root systems and form fruit, and potassium to promote flowers and develop resistance to disease. So, change to a low nitrogen and high phosphorus and apply once in the spring and once in June.

3. Some species clematis will need to three to five years to become a fully mature plant, and can refuse to bloom during this stage of their lifecycle. That being said it is not uncommon for a few blooms to be produced while young.

What can be done to encourage flowering?

Only to allow time to pass, and avoid overfeeding with high nitrogen fertilisers