How do I apply bone meal to my clematis?
After the petals of the many blooms fell off, the finely spiked centers remain on the branches. Should I cut them off to encourage new blooms?
How and when to prune and deadhead clematis depends on the type of clematis you have. This article gives you general growing guidelines: https://www.gardeningknowhow.com/ornamental/vines/clematis/growing-clematis.htm
and this article goes into a little more detail: https://www.colostate.edu/Depts/CoopExt/4DMG/Flowers/Vines/prunclem.htm
I have an Earnest Markham growing against my single story wall. It has reached the top and wants to continue to grow, but it has nowhere to go. Can I cut the tips off and hope flowers will appear lower down on the plant?
Clematis growers believe pruning is an essential part of raising clematis. Ernest Markhams are the type that flower in late summer from new growth. Here are a couple of article that will tell you more about pruning your plant: https://www.gardeningknowhow.com/ornamental/vines/clematis/pruning-clematis-vines.htm
I can tell some of the vines are still green inside, but the outsides are brown and dry. Did I not give it enough water? It is getting quite old, probably 30 yrs or more. It has always been hardy till now. It is the usual purple variety.
Since your vine is well established and has been doing well, it sounds like you've been taking care of it correctly. Have there been any environmental changes, like some kind of herbicide getting on it, or some change in soil or water? If not, the problems must be pests or pathogens.
Here's one strong possibility: https://www.gardeningknowhow.com/ornamental/vines/clematis/clematis-wilt-treatment.htm
You can always take some soil, branch, and leaf samples to the Extension Service for analysis. This article will help you find the nearest one: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm
If you decide to prune your clematis, this should help: https://www.gardeningknowhow.com/ornamental/vines/clematis/pruning-clematis-vines.htm
6 foot of bare stalk, leaves and blooms along the top. What am I doing wrong? Whereabouts do I prune when flowering is finished? Thank you.
It's impossible for me to tell you what's wrong with just a description of a plant losing leaves. You need to become the detective now, and using the following article, look at the maintenance of your plant, and see where it's failing. https://www.gardeningknowhow.com/ornamental/vines/clematis/growing-clematis.htm
Pruning will depend on the kind of clematis you have; hopefully you have that information.
What is wrong? It bloomed well earlier, but now vine is brown and only few leaves still green.
This article discusses several aspects of clematis care for you to look at to see if your plant is lacking an any area: https://www.gardeningknowhow.com/ornamental/vines/clematis/growing-clematis.htm
If your plant is still alive, and if you take measures to correct problems, you could have more flowers next season. To see if the plant is alive, bend the branches - if they snap apart, all brown and crispy, they are dead. You can also scrape the outer bark off larger branches to see if there is green tissue underneath
What is the best fertilizer for my clematis?
Use a fertilizer high in phosphorous on your clematis. Something that is about a 10-20-10 NPK ratio or even rose food can be used to fertilize clematis. Anything having too much nitrogen will only result in an abundance of foliage growth with few blooms.