I have a spring blooming clematis that gets a west sun exposure, blooms profusely for about 2 weeks then all the petals fall off the plant, is it getting to much hot sun? I have alot of mulch around the roots to keep them cool and put a slow release fertilizer on it. What am I doing wrong?
Blooms that don’t last are one of the great frustrations of gardeners! In the case of your clematis, the reasons could be environmental: temperature fluctuations like those we have had this spring can greatly affect the longevity of plant blooms, as can severe weather such as heavy rainfall and high winds. Exceptionally hot weather and insufficient watering can also contribute to blooms not lasting.
Low soil fertility can also affect the continuance of blooms. You have used a slow release fertilizer, but fertilizing can be tricky and can itself be the cause of a shorter bloom time, depending upon the formulation you have used. Some experts recommend a balanced 10-10-10 granular fertilizer monthly from early spring until blooming begins, and then discontinued through the flowering period. Some fertilizer formulations may encourage root growth at the expense of flowers.
Mulch has many benefits, but it can cause problems when it is placed too closely to the stem of your clematis. Although its ability to retain water is one of the things we like about it, mulching too closely can lead to diseases such as root rot in soft stemmed plants. A distance of three or four inches away from the plant is recommended. Some gardeners plant large-leaved plants such as hostas at the base of clematis vines to shade them and keep them cool.
Whether or not you fertilize or add mulch, it is always a good idea to amend your soil each year with organic material: a layer of compost will continue to enrich and improve the soil throughout the year.
You might find this website interesting – it is truly for clematis lovers everywhere: https://www.clematisinternational.com/links.html