Does Buddhism kill creativity?

Buddhism is the Development of creativity, Creativity is human nature, it is the sole reason for the rapid advancement of human kind, and Buddhism grounds our creativity with purpose. It's not easy being an artist, we get "lost in the clouds" sometimes and we give credit to the chaos that we call "the Creativity process" Creativity is not a process Stop assuming it is. If you have to think to hard to use your creativity its because your actually just thinking. And Apple is not a representative of creativity, they are programmers, the ego is a program, a strategist. creativity is intuitive, it is effortless. I'm 32 years old, i ether, draw, paint, sculpt or write every day, I have never had a creative block, and as a child i assumed that a creative block is just what people who weren't artistic. With a Buddhist understanding Creativity is your true human nature that develops thru the pure mental state that comes from contentment in meditation (natural state of human development free from selfish motives). Evolution is pushing change but this human form is optimal for the harnessing of creative. I would recommend doing some intuitive paintings like splatter paintings so you can get a taste of actual pure creative energy, that is meditation for artist and unless it is extracted from enjoyment in the moment and free from egotistical subject matter you are not living an authentic life. Authenticity is opposite of ego, I believe now as an adult that creative block is more of a conflict of what you believe to be important enough to show devotion to. You need to take a long look in the mirror, find the doubt in your practice, have faith that doubt is one of the five hindrance that dissipates with the defining of phenomenon and eradicated with meditation.

Maybe you can use your (new) interest for Buddhism as a new subject of your work - like focusing more on themes like human emotions (compassion), impermanence etc.

Creativity and compassion are by-products of consciousness. Creativity is driven by ego before Nirvana but after that it is an effortless spontaneous process. If you live consciously you will not compete but will start living creatively. In Buddha's time you could be creative in a very restricted sense. An engineer would not go beyond creating a new knife or a plough. Today one can express his creativity in a number of ways and extent that was not possible in earlier times. Buddha was never questioned about creativity.

If you follow Buddha, you will be creative. Buddhism is restrictive in nature because of dos and donts by dont-know-whos. Nature is very creative. There are no copies in Nature. Humans are creative by birth but unfortunately society kills it through dos and donts especially religions. Creativity is synonymous with egoless-ness provided one does not aspire to profit from it.

If you are creative you will be alive and very close to Nirvana. Buddha was so creative with his approach. He was unique. How can his teaching go against creativity which is uniqueness manifested?

Meditation, as I believe, enhances your creativity as it makes you thinking more clear.

I think that following through an idea and turning it into a finished piece of work requires quite a lot of attachment and devotion to the project.

Mahā,nidāna Sutta describes the pursuing of worldly activities. In the light of this, what might be happening here is you have some attachment to the finished work a pleasant feeling arises which triggers the following steps:

dependent upon feeling (vedanā), there is craving;
dependent upon craving (taṇhā), there is seeking;
dependent upon seeking (pariyesanā), there is gain;
dependent upon gain (lābha), there is decision-making;
dependent upon decision-making (vinicchaya), there is desire and lust;
dependent upon desire and lust (chanda,rāga), there is attachment;
dependent upon attachment (ajjhosāna), there is possessiveness;
dependent upon possessiveness (pariggaha), there is avarice; 
dependent upon avarice (macchariya), there is safe-guarding;
dependent upon safe-guarding (ārakkha), there arise various evil unwholesome state — 
   taking up of the rod, taking up of the sword, conflicts, quarrels, disputes [strife], back-biting, harsh speech, false speech.

Mahā,nidāna Sutta

My decrease in creativity does most likely not have anything to do with my feeble meditation attempts, because it is natural to have ups and downs, even when it comes to creativity.

This seems like you self defence mechanism kicking in creating negative states. You are trying to protect or guard your creativity.

In addition greed and craving may propel you to undertake more work as perhaps a source of income. You can still keep up your motivation without greed through proper intention.

Without meditation you decision making maybe fueled by gains than creativity. Also craving and excessive desire (perhaps at the sub conscious level) to make a living may be having a detrimental effect on your creativity.

I suppose my real question is: is it possible to balance being a practicing Buddhist and a creative artist?

Yes you can. If you are motivated by proper intention than craving hence avoiding the above path. Meditation also clears your mind and makes you more emotionally balanced so your creative juices can run wild.

Attempts to be mindful, ala mindfulness practices, are certainly at odds with "aha" creative experiences as these emerge out of a wandering mind:

See: Mind wandering “Ahas” versus mindful reasoning: alternative routes to creative solutions http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4469818/

So, should one strive to be mindful, or should one allow it to unfold naturally, as a result of meditation, alternated with activity?

As this Soto Zen master says: Stop being mindful! http://antaiji.org/archives/eng/adult18.shtml

As Maharishi Mahesh Yogi said: The two steps of progress are rest (TM aka dhyana) and activity (everything else found during waking, dreaming and sleeping).

An enlightened person, at least in the beginning stage, is where the qualities of rest (meditation) have spontaneously emerged and become permanent in the middle of all possible activity (waking, dreaming and sleeping).

One doesn't cultivate this by attempting to BE mindful, but simply by allowing the natural cycle of rest and activity to proceed.

And mind-wandering is the essential basis of dyana and the spontaneous ability to switch from paying attention TO something and switching attention (via mind-wandering) to something else IS the creative process. In enlightenment mind-wandering is always present, even when one is fully focused on some thing, and so creativity is always present as well.

Mindfulness, in this situation, merely refers to the ever-present observer, always observing. Such a person is always mindful because it is impossible for the ever-present observer to NOT be mindful.

This confusion is why people worry that BUddhism detracts from creativity. It isn't Buddhism that detracts, but inappropriate attempts to practice what spontaneously emerges from practice: being always mindful.

The "description" that one is always mindful when one is enlightened has become a "method" to use to become enlightened.

This can only take one further away from enlightenment, which is where one is always creative because the mind is always free to wander.

Many working artists are also Buddhists. A number of high profile creative people such as Leonard Cohen, Herbie Hanc**k and Steve Jobs are Buddhists. See Wikipedia's long list of celebrity Buddhists, many of whom work in creative industries.

Most people report that creativity increased after taking up meditation. At least one scientific study reported that meditation enhances creativity. The Huffington Post has reported much the same news.

Buddhist practice requires not just moment to moment awareness, but also considerable continuity of purpose. If one emphasises only the former then one is unlikely to make much progress. It's a bit like walking downstairs and forgetting why you went down there.

So there seems to be no reason to think that being a practising Buddhist would "kill creativity". And no reason to think you cannot balance being a practising Buddhist and a creative artist. I personally know at least a dozen people who do just this.